Sciencemadness Discussion Board - Interfacing 80's UV VIS

Interfacing 80's UV VIS

hector_carbossa - 30-11-2008 at 10:55

Good Morning.

Very nice forum. This is my first post. I'm a biotechnologist. Unfortunately I'm not omnicomprensive as the associated ideal figure. On the contrary, sometimes I think this quality wouldn't be strictly necessary, especially in my trials described therefore.

I've an old Carlo Erba UV-VIS spectrophotometer, the spectracomp 602. This and older models, are nowadays anymore used and cited in many scientific publications. Thus, the temptation of utilizing it in sparetime.

It seems not to miss any internal part, except D2 UV lamp.
It has a rs232 plug and a 50 pin internal parallel plug, I presume for a TTY.

The problem is the total absence of buttons on the instrument. I know (in my fairy world) there are some software that allows data aquisition from various instruments. I've seen one article with a Perkin Elmer Lambda 2 data seen from Windows XP. Anyway, this software wouldn't allow me to control the instrument and I doubt more "magic" softwares exist.

When connected to a computer and powered on, serial comunication software don't recognize it.

Obviously, this is my personal troubleshooting flow. Missing a specific software, the only logic way(?). Someone is in the same situation or knows something useful?

Thanks to all. In any case I hope this argument be worth interesting.

not_important - 30-11-2008 at 20:15

Perhaps someone could get this dcument

Quote:

Rejuvenating Old Computerized Spectrometric Instrumentation: Discussion of Two Case Histories

Computerized analytical instruments of late 70's and 80's are facing rapid technological obsolescence, although they are often retaining good analytical performances. Responsibility is to be attributed to the fast advance in computer technology, which is leaving little or no back-compatibility with old standards and data formats. Rejuvenation may be reached by simple hardware and software modifications, to allow data exchange with modern PC's and LIMS. Two typical case histories for spectrometric instrumentation of late 70's are then presented and discussed in a general fashion.

http://www3.interscience.wiley.com/journal/108061173/abstrac...

Pay it forward

smuv - 30-11-2008 at 21:05

Rejuvenating old computerized spectrometric instrumentation: Discussion of two case histories

Annali di chimica, 2004, vol. 94, no3, pp. 155-163

Attachment: Old_spectros (125kB)
This file has been downloaded 812 times

Saerynide - 30-11-2008 at 22:44

Haha, I had just asked my university library to get it for me so I could post it... Oh well

[Edited on 12/1/2008 by Saerynide]

undead_alchemist - 1-12-2008 at 01:06

Here is some other info that one university did to interface an old Perkin-Elmer Lambda 3B Spectrophotometer
http://technology.niagarac.on.ca/sop/Lambda3B-SOP-V2.pdf
http://technology.niagarac.on.ca/sop/Lambda3BOperatorsManual...

hector_carbossa - 1-12-2008 at 02:46

Hi and thanks to everyone.

Whole Dossi's publication seems to clarify many hotpoints. I've seen right I've to try with a terminal program. I tried with programs such as Docklight, DACIO and Bytewedge, but, first to all, I am not so skilled to use them (I'am a biotechnologist). However, no single bit seemed to came from device to the pc (a 1.2 GHz P3) COMn. I think I've to build an adaptor as the one described. Anyway, my model certainly would be a little recent than Dossi's. It haven't built-in keyboard but it has a RS232 that I believe missing in the article's 601 model.
I already read latest two documents and I further tried that software without success neither comprension of what I was doing.

I'll try some configurations (including new cables) nonetheless searching more articles in my faculty info lab.

I hope I obtain some results soon. In case of success (or failure), if you're interested, I shall post something worth.
In the meantime I say again thanks to all.

watson.fawkes - 1-12-2008 at 06:32

You might have to exhaustively search through the serial port parameters, trying each in turn, to find out what the defaults of the port on the device are. Just using COM1 or COM2 isn't enough. You'll have to configure the parameters of baud rate and parity. These change the encoding on the wire, and if you get the wrong encoding, nothing will transfer, even if the port is actually working.

You may well have cabling issues, particularly if the port uses what's called "hardware flow control", which requires certain non-data wires to have the correct signals on them. There's an old tool called a breakout box which can be used to experiment with such problems. If you need one, you want to get one with blinky lights on it so you can see the signals.

hector_carbossa - 1-12-2008 at 15:51

Hi. Today, I changed RS cable with a newer one of the same type. Now I can recognize device with WinDAQ Hardware Manager and obtain a response in terms of bit received when I send random data with DACIO, but nothing appears there. I tried powering on when I was already connected throuhg terminal in order to receive all possible data. Conseguentely I've to reboot device everytime to assure nothing is lost.

Quote:

You might have to exhaustively search through the serial port parameters

You're right. I tried at 600 and 1200 bauds. At this time I prospect myself a lot of reboots and fills in a trials table.
I believe that is being a little too intuitive work.

Eluding paranoys, I did my few test with various software but nothing appears I think for this main question.

Quote:

You may well have cabling issues

If I correctly understood, a pin on device may not have match on PC's port. Thus I should use a crossed cable that generally seems more indicated for non-modem communications. I don't know how old terminal's/pc's RS232 could be changed in twenty years. I'm relatively luckier than Dossi because I haven't to build an adaptor but perhaps less experienced.

Quote:

There's an old tool called a breakout box

I used a presumable breakout box emulator using two serial ports, TalBreakout. When I turn on the instruments, (nul) string appears and nothing else happens. What means this? I know this may not be the same thing. However I'll try (this word begins to be persecutory) to get some information about real tool.

In next step I'll look at crossed cable and nonetheless at some theory.

Thanks again
Goodbye

[Modificato il 2-12-2008 da hector_carbossa]

watson.fawkes - 1-12-2008 at 16:34

I presume you mean this emulator. That will work once you already have cabling working, but it may not be particularly useful in getting the right cable. If you can't get it working, I do heartily recommend a hardware breakout box.

I should point out that hardware flow control was quite common on old serial ports, back when the electronics to keep up with a "full-rate" serial connection (9600 bps) was expensive and (hence) not universal. If your equipment is old enough, it almost certainly needs extra signals asserted before it sends any data out. I can tell you through old experience that it's a real annoyance.

Finally, seeing "(nul) string" is usually an indication that the baud rate is set wrong. It's probably a good sign, because you're at least seeing something, which means your transmit and receive wires are likely connected correctly.

not_important - 1-12-2008 at 23:11

You'll need to find specs on your particular equipment, to learn exatly what the serial port is.

If the serial interface is RS-232 then generally some futzing with RTS/CTS, and maybe DTR or DCR, is needed; this is the hardware handshaking for equipment ready and data flow control.

That PDF on rejuvenating old gear states that the Spectracomp 601 spectrophotometer has a built-in 20-mA current loop serial interface. This is not directly compatible with voltage level RS-232, which is why they built that adapter circuit as an interface between the two.

You can figure this out with an oscope and a few resistors, but the spec sheet might be quicker.

hector_carbossa - 2-12-2008 at 14:21

Hi. Today I changed cable with a crossed one resulting in none results. A thing I havent wrote it's that (nul) came out also when I turn off device.
Obviously, I'll get away from this approach (there are at less 320 different combinations).

Thus, looking at diagnostics I may use BOB or scope but I absolutely don't know what information I can get from there. I think I can see if effectively there's signal on sending pin. Unfortunately at this time I only have an audio board scope emulator software. I may build a basic probe connecting sending pin in series with resistor and + mono jack's and - to common ground. At that time, if there won't hardware problems I may see something as signal or peaks. Thus if timescale's precision shall be affordable I shall use peaks delays to calculate correct baud rate. Starting resistor may be 20 ohms hypotizing a current less than 50 mA. This method's main problem's I cannot go over 1 V. This workflow I can derive from mainpoints you stated.

I'll start as soon as possible.
Thanks for suggestions.

[Modificato il 2-12-2008 da hector_carbossa]

[Modificato il 2-12-2008 da hector_carbossa]

watson.fawkes - 2-12-2008 at 15:04

Quote:

Originally posted by hector_carbossa
Unfortunately at this time I only have an audio board scope emulator software. [...] This method's main problem's I cannot go over 1 V.

RS-232 is voltage driven, and those voltages typically don't go over 12V. I think the specification allows up to 24V or so, but I never saw anything over 16V or so. Therefore, make yourself a 25x voltage divider probe and your audio card should work fine. This requires only a pair of resistors in the ratio 1:24.

hector_carbossa - 2-12-2008 at 15:41

Thanks, this seems better than simple resistor or 5,5 diodes series.

Sauron - 3-12-2008 at 05:17

Well, as you are finding out, RS232 hardware is not all created equal and you really need them pinout for your unit and the correct matching cable. I have run up against this hassle before with older Waters serial controlled PDA UV detectors, like models 990 and 991, which were controlled by a dedicated Fujitsu (as I recall) PC running an elderly DOS of the IBM flavor (PC-DOS) and software written by a company still extent in the HPLC column business. The machine was controlled by two special proprietary RS232 cards installed in ISA slots in the PC and connected by cables to the detector.

I had the detector, but no old PC, no cables, and no special boards. I did manage to obtain the software and correct version of PC-DOS and get it running on an old HDD. But lacking the cards and cables...

LabView of course could be of no help, it was a lost cause.

hector_carbossa - 3-12-2008 at 16:26

Hi.

Scope test: preliminary setups for decent scopic data retrieval.
Random test: A thing I have forgotten for long time that previous unknown user shortened pins 2 and 4 with a piece of metal wire. What did it means? And what is effective use of "Terminal" 25+25 parallel port?

Quote:

RS232 hardware is not all created equal

No datasheet exists. So I've now random pining in best case.

Quote:

The machine was controlled by two special proprietary RS232 cards installed in ISA slots

Some things may be not all-in-one. This may happen.
I don't know your instrument's year. Mine's 1984's.

However I mantain expectations because it probably has built-in microcomputer which only processes, sends data and receive simple commands. Previous model has this setup according to Dossi's work.

The only thing to do now is optimizing the scope test.
I also may use win NT I already have on test's PC.
Broken microcomputer should be an hypothesis to take in consideration at certain point.
In effect there's a gambling component.

Goodbye.

not_important - 3-12-2008 at 17:44

Quote:

Originally posted by hector_carbossa
Hi.

Scope test: preliminary setups for decent scopic data retrieval.
Random test: A thing I have forgotten for long time that previous unknown user shortened pins 2 and 4 with a piece of metal wire. What did it means? And what is effective use of "Terminal" 25+25 parallel port?

This doesn't sound like standard RS-232/DTE/DB-25, for which pin 2 is transmitted data and pin 4 is RTS, which often would be tied to CTS (pin 5). RTS/CTS is a common hardware handshake flow control, connecting them together at each device generally allows the port to operate with no hardware handshaking, and thus no need to run wires for those pins. Connecting TD to RTS akes little sense.

You may need to figure out the interface part of the port hardware, to determine what the pinout is and if it is RS-232, current loop, or something else.

I'm not understanding your last question.

hector_carbossa - 4-12-2008 at 05:52

Sorry, perhaps I misexplained. I've DB9 on device such as on PC. Thus tx should be pin 3 and tx "must" send anything and effectively do it but I couldn't recognize signal structure due to software's saving function lacking.

Other connector is substantially blue one you can find on LPT1 printers, but has two linear arrays of 25 pins for total 50 pins.

With probability them are these.

Only now I realize it may be dedicated terminal or telewriter cable. However DB9 should be necessary for real computer controlling. But I recommend you taking this information with pliers.

Dossi adapted pre-RS232 to DB25 using just txs and rxs. I need in my case, only DB9 cable. So I thought there may only to set right configuration. But this is only an hypothesis.

Sauron - 4-12-2008 at 06:03

The connector I am talking about was DB-37

Waters used/uses same connector for power cable between controller and HPLC pumps in the 600 analystical and also the preparative series, they look like a "standard" PC cable but not so as they are quite special. Waters sells these cables for about $500 US. I have several of them. The ones for the 600s are not same as the ones for the prepLCs. Not interoperable.

The serial control cable for the 990/991 Waters PDA looked same but no telling what the pinout was. (No original cable to reverse engineer.) I have several of them.

Not at all like your little DB9.

hector_carbossa - 4-12-2008 at 15:22

Today, unable to find signal logger I opened device for looking at wires colors.

From left to right I annoted upper pins:

1: green/yellow (tipically ground colors)
2: violet
3: white/orange
4: blue
5: yellow

6, 7, 8 and 9 are unused. This induce to think configuration may be simple as in Dossi's publication: send, receive, rts and cts or something similar.
At this time seems better I follow hardware approach.

This was most simple trial from beginning. Now I may build very simple BOB with 25 ohm-led in parallel with 1 ohm and connecting each to random match (most intuitive) on PC's port that should be on basal signal.

This It's only hypothesis but the most promising.

watson.fawkes - 4-12-2008 at 15:59

Typical buffer chips for that generation of equipment were the 74LS244 and 74LS245, whose inputs and outputs would be directly connected to the port. They were typically socketed because they had a tendency to blow out. The color code on the wires is without meaning; there was no standard. On the other hand, if you trace out the connector pins to (presumably) the pins on the IC's where they connect, you may be able to determine, with the help of a data sheet, which are the inputs and which are the outputs.

hector_carbossa - 5-12-2008 at 11:32

Ok. I used simply quite resistant boxy shaped leds. I turn on PC, then I turn on device.
I noted this (real numbering):

5: nothing
4: permanent light until I turn on (CTS?DTR?)
3: permanent light when I turn on. (RTS?DSR?)
2: nothing
1: nothing

I don't know signal on 4. When I turn on, pin 3 transmits RTS signal (logical 0 or 00000000 also I seek with binary port manager).
Pin 1 and 2 should be tested to find transmit and receive. 1 with probability is ground.
At this point I may think test connection like this:

5 --> 5
4 --> 8
3 --> 7
2 --> 2 or 3
1 --> 3 or 2

Here it's obvious it isn't standard. I tried with 5(5) 4(8) 3(7) 2(2) 3(3). It doesn't work with every cable. Now I have to try various combinations.
Nonetheless I may try repeating BOB test for each pin to ground.

UPDATE

In last trials, no combination seems useful. I extracted I/O board but I haven't found those chips. There are four long AMD's chips named P8255APC or something similar. However seems impossible to get pinout by this way.

However in I/O board there are some switchs for baud rate selection from 75 to 4800. At this point new combination trial with correct speed is required.

Another thing it's I obtain (nul) in each configuration. Naturally I tried all configurations with 5(5).

I don't know if 80's microcomputers have a BIOS but I'll check battery if there's one

Goodbye

[Modificato il 6-12-2008 da hector_carbossa]

[Modificato il 6-12-2008 da hector_carbossa]

watson.fawkes - 5-12-2008 at 18:22

The P8255APC is an 8255A "programmable peripheral interface" chip. See the Wikipedia page. Each chip does 8 bits of data, for a total of 32 bits total. My guess is that those 50 pin connectors (so-called Centronics connectors) are some kind of daisy-chained laboratory bus, so that two of the 8255A's are dedicated to upstream and two to downstream. In any case, these chips weren't used for serial port interfacing.

The buffer chips I mentioned are much smaller. They're 20-pin DIP chips. Other buffer chips were used, though; I mentioned the ones I recall. If you can trace out the IC pins that the serial port pins connect to, it might well tell you which of your pins are inputs and which are outputs.

At a maximum of 4800 baud, you will definitely have to get the hardware flow control working. With five pins, it looks like you have 1 ground, 1 Tx, 1 Rx, 1 each flow control in/out. You're likely right that pin 1 is signal ground; that was typical. As for the others, I don't know.

It's typical for gear to send out a "hello message" when it turns on. You will probably have to enable flow control to see this. (A hint: at 75 baud, you can see the individual bits on the breakout box. They're fast, but distinctive.) For the purposes of debugging, you can tie the appropriate pin either high or low (it might be either). Tie a pin low by connecting it to ground with just a wire; tie a pin high by connecting it to +5V with a 10K resistor.

hector_carbossa - 6-12-2008 at 12:31

Hi. At bottom of this post there are results (not all) with at 75-110 baud setting. I recognized with two antiparallel leds in series with each pin. I noted no single bit flowing perhaps sensorial precision may be influent (or I have to trash everything).
Because it's impossible negate that results list reading may be boring I can condens it here in principal current flows (first's devpin, second(s) crossed cable pins)

2 from 7, 8
3 to 3 (COM's 2)
3 from 4 an 2 (COM's 3)
3 to 7 when on
3 from 8 when off
4 from 7 when on
4 from 8 always
1 from 8 more when turn on
3 to 5 when off

This excluding single pulses in opposite flows. I omitted here, but already tested, connections with COM's ground, that results always in low glowing except for pin 3 that's brightest.

I would prefer table but there's no way to make decent one (all combos are Device Pin - COM Pin):

2-7
1. on
  1. in continuous signal
  2. out single pulse
2. off
  1. in maybe pulse
  2. out maybe pulse
2-8
1. on
  1. in continuous low signal
  2. out nothing
2. off
  1. in continuous low
  2. out nothing
3-2
1. on
  1. in nothing
  2. out continuous signal
2. off
  1. in nothing
  2. out nothing
3-3
1. on
  1. in single pulse
  2. out continuous signal
2. off
  1. in nothing (pulse when turn off)
  2. out nothing (pulse when turn off)
3-4
1. on
  1. in continuous signal
  2. out single pulse
2. off
  1. in s.p. when t. off
  2. out s.p. when t. off
3-5
1. on
  1. in nothing
  2. out nothing
2. off
  1. in nothing
  2. out nothing
3-7
1. on
  1. in single pulse
  2. out continuous signal
2. off
  1. in s.p. when t. off
  2. out s.p. when t. off
3-8
1. on
  1. in nothing
  2. out nothing
2. off
  1. in continuous signal
  2. out nothing
4-1
1. on
  1. in nothing
  2. out nothing
2. off
  1. in nothing
  2. out nothing
4-2
1. on
  1. in nothing
  2. out nothing
2. off
  1. in nothing
  2. out nothing
4-3
1. on
  1. in single pulse
  2. out single pulse
2. off
  1. in s.p. when t. off
  2. out s.p. when t. off
4-4
1. on
  1. in nothing
  2. out nothing
2. off
  1. in nothing
  2. out continuous pulse
4-5
1. on
  1. in nothing
  2. out nothing
2. off
  1. in nothing
  2. out nothing
4-7
1. on
  1. in continuous
  2. out single pulse
2. off
  1. in lights off
  2. out s. pulse
4-8
1. on
  1. in continuous
  2. out nothing
2. off
  1. in continuous
  2. out nothing
1-7
1. on
  1. in very low light
  2. out nothing
2. off
  1. in nothing
  2. out nothing
1-8
1. on
  1. in continuous
  2. out nothing
2. off
  1. in lower continuous
  2. out nothing

[Modificato il 6-12-2008 da hector_carbossa]

[Modificato il 6-12-2008 da hector_carbossa]

[Modificato il 6-12-2008 da hector_carbossa]

[Modificato il 6-12-2008 da hector_carbossa]

hector_carbossa - 6-12-2008 at 20:39

Draw back to simpleness, but not to defeat, I used again one of that programs that should monitor COM ports. I used one in which some virtual leds called DSR, CD, CTS and RI.
One only pin activate CTS indicator. Another pin activate either DSR and CD (I think in crossed cable they are shorted). It's also possible to check a box called DTR but I think now I came in new field.

I haven't seen bits with leds nor with programs (except logic 0 on some ports).
Some combinations with ground, presumable CTS and presumable DSR at right positions and remaining T and R at right speed don't work. Only my ignorance supports me to go forward (an naturally your hints). Why? A thing I don't know is how work non data cables in overall protocol. I noted continuous signal, that may be right due to its presence on same COM port's position.

At this point, having minimum combination, I have to know what may be wrong with software so I returned to parameters trouble. Last thing I think is theresn't no data for a question of "authorization" to send. Now I remembered an "inverse" trial I performed in firts few tests. Port's signals are different when I turn them listening. Thus, opening port when device is already initialized may be needed event (if I havent burnt all in the meantime).
Contrarily to routine in which devices has to be connected to pc ready to recognize them, pc (or "dumb" terminal) as to be connected to device. Device is the computer.
Just to break eggs in my chest I noted nothing appears when, sometimes I closed and reopened port.

Due to my inphormatic's lacks I can't discrimine any informationless situation from a situation that prepare me to being a rare gold plated integrated's merchant (this is dreaming reality I imagine to buffer mental status soon I'll be condemned to).
In effects, who suggested to leave all wasn't completely wrong. Fact is I already left all some months ago. This is "the final challenge". Time to kick RS232's "luck" hasn't came yet (at this point only shifted).

Goodbye

[Modificato il 7-12-2008 da hector_carbossa]

[Modificato il 7-12-2008 da hector_carbossa]

[Modificato il 7-12-2008 da hector_carbossa]

watson.fawkes - 7-12-2008 at 09:31

The trial where you got "continuous pulse" is likely one where your unit was sending on boot.

Also, if you're using LED's and can scrounge up a 5V power supply, you can test the unit in isolation without using a serial port. It's a matter of tying various pins high and low and looking for data pulses. After you've determined where the Rx and CTS pins (receiver data and control) are, making a cable is a matter of looking up the pinout for the other side.

hector_carbossa - 7-12-2008 at 11:36

Hi. Today I did "inverse" tests. I shorted pins already shorted when I found device plus some other combinations. I shorted port's CTS/RTS and tried two combinations of remaining pins on 2 and 3. This doesn't run.

I also tried setting port from device manager, disabling FIFO (random test) but nothing.
Thing for what I hope I'll be forgiven, it's I noted one time, when I moved wires on powered device, some activity from it.

However, regarding continuous pulse, I'm sorry but I expressed result unclearly. I have continuous signal when off and single pulse when I turn off. Sorry again.

Test with power supply may be informative if it can give back different results than previouses. I've some ATXs. Thus, I have to reset to 75 baud and connect each pin throug led and 10k one time to ground, then to +5 eventually restarting.
In effect I have only to find hardware control pins which one of then has real continuous out signal (logic O) to ground then logic 1 pin has continous in signal from +5V.

Pinout on the other side may be 7 or 8 but for a profane than me they may be DTR/DSR with same probability. Nonetheless I think crossed cable (that lost any sort of meaning long time ago) at this point may have shorted 1 and 6. Not 7 and 8 or 4 and 6 because this may had seen with programs but I'll test all connections.

Finally, the other connector seems with probability SCSI DB50 female but I don't know was it used for. "Terminal" label doesn't leave me any doubt it's printer reserved (Local Printer Terminal).

hector_carbossa - 8-12-2008 at 12:33

Hi. Today I performed further high-low test on 75-110 baud connecting each pin to 10 k- antiparallel led series. These results seems to be sometime paradoxal but I implied device's feedback to each tension. However a -3V exit may have been interesting. Escaping from all possible conclusions, pins 3 and 4 seems to have similar and opposite behavior, respectively: always pulses in/out then continuous signal out/in and peculiar stepping-glowing down. My "biochemical" approach make me to say 3 and 4 nature seems different than 1 and 2.

However, I used simple resistor instead of parallel of leds-resistor/wire excluding ATX's "signal" effects on system. Anyway these effects seemed to attempt with this configuration. +/-12, -3 tests may be useful but should be too hazardous.

In addition, pulses seems to be slower at 75 baud than at 2400.

Next tests I'll try will use normal cable to have minimum influence by shorts.

Results are:

- GND
  - ON cont. in
  - OFF
- +5V
  - ON long single pulse in
  - OFF continue fading down out
- GND
  - ON cont. in
  - OFF
- +5V
  - ON pulse in
  - OFF fading down out
- GND
  - ON pulse in then continuous out
  - OFF pulse in then pulse out
- +5V
  - ON pulse in then cont. out
  - OFF fading down out with discrete steps
- GND
  - ON pulse in then pulse out then continuous in
  - OFF pulse in then pulse out
- +5V
  - ON pulse in then pulse out then continuous in
  - OFF pulse in then stepped-fading down out

watson.fawkes - 8-12-2008 at 19:02

If you're seeing pulses that vary by baud rate setting, you've likely got data. To see if you can receive it, make a 2-wire cable to your PC--one wire for ground and the other for data. Leave the rest of the pins configured identically on the breadboard so your flow control works. See http://pinouts.ru/SerialPorts/Serial9_pinout.shtml for pinouts on the PC side, where you'll want (in the symbols of that page) RXD and GND. You might well be able to see the data it's sending with ordinary terminal software.

hector_carbossa - 9-12-2008 at 15:23

Hi. No combination with CTS/RTS pins works. Perhaps I'm unable to receive data for various reasons or there's not data but only mark signal.

However, I shall connect presumable controls with DTR and DSR. I also shorted each pair trying reception but nothing appears.

A thing to clarify worth pulses: I never seen alternating light on/off but only one alternation. Nothing similar bit flow and nothing useful in discriminating a tx from a CTS or something similar. Only difference stay in behavior on the test. 3 and 4 has same on/off sequence but opposite leds (and signal) states.

At this point there's software or hardware cause. Mechanical calibrations always are performed automatically but I may confirm them are different with some combinations but this is probably madness.

Finally, having a program that shows me received data, then parity, stop and lenght may have secondary importance. The fact is there is no data. If this is due to software configuration I'll never discover correct pinout in human-friendly periods. But this seems unprobable as conseguence debug programs are made mainly to view data.

Only DSR/DTR combinations separe me to defeat or success but now I doubt.

ANOTHER THING

An additional cause in the caotic realm of presumable causes may be absence of deuterium lamp that incide on starting controls but absence of something notify this makes this hypothesis opinable.

[Modificato il 10-12-2008 da hector_carbossa]

[Modificato il 10-12-2008 da hector_carbossa]

hector_carbossa - 13-1-2009 at 14:23

Hi and happy new year. As you imagine theresn't news about RS232.

Today, I found whole TTY(??) with phosphor screen and keyboard and a voice whispered me again to try the SC602. The problem is the strange connector. For this reason I haven't taken it yet.
Connector seems to be a DB50 as three rows of pins. If it is I may find a cable and simply try. Yes, this may be less comfortable than excel and there's new risk of mismatched cable and broken screen, paper unavailable, rare cable, broken keyboard...

densest - 16-1-2009 at 18:29

hmmm.... there is a term for reverse-engineering old computerized equipment: "necrocomputing"

Older equipment with DB-25 pin connectors are often run at 1200, 2400, or 9600 baud.

Using antiparallel LEDs with 10K ohms in series, one can decode what the connector is intended to do.

There are a lot of RS232 references on the web, but they are often not very useful to a beginner.

Do you have access to an ohm-meter ? A combination voltmeter-ammeter-ohmmeter should cost less than (euros)20.

Pin 1 is "frame" or "protective" ground. It is connected to the chassis. It is usually NOT connected to any signalling device.

Pin 7 is "signal ground" and is the reference for all other voltages mentioned here.
Usually, pin 1 and pin 7 (if pin 1 is connected at all) are shorted together and an ohmmeter should read close to 0 ohms (less than 1) between them.

The interface is asymmetrical: it was designed to connect a user device (DTE, data terminal equipment) to a modem (DCE, data communications equipment), so all pins are connected to a transmitter on one end and a receiver on the other. You can tell which is which by using the voltmeter or the LEDs. Connect the reference point to pin 7, and measure the voltage or observe the LEDs.

Assuming that a voltage:

NEGATIVE more than 4 volts with respect to pin 7 is GREEN
POSITIVE more than 4 volts with respect to pin 7 is RED
less than 2 volts POSITIVE OR NEGATIVE with respect to pin 7 is DARK.

A pin with a transmitter will show either RED or GREEN.
A pin with a receiver will show about 1 volt positive or DARK.
A pin which is not connected will be DARK.

The computer DE-9 connector is defined to be DTE. It is very likely that the instrument is also wired as a DTE. In the spec, these are not allowed to connect to each other. In the real world, it is done all the time,so there is a well defined way to do that.

First, see if pin 2 or pin 3 on the 25 pin connector is connected to a transmitter. Whichever one is connected should show GREEN as the idle state of an RS-232 line. The other pin should be DARK.

The other useful pins are 4, 5, 6, 8, and 20.
Connect 4 to 5
Connect 6 to 8 to 20.

On the PC end, connect:
7 to 8
1 to 4 to 6

Connect the transmitting pin of 2 or 3 on the 25 pin connector to pin 2 on the PC
Connect the other pin (3 or 2) on the 25 pin connector to pin 3 on the PC
Connect pin 7 on the 25 pin connector to pin 5 on the PC

Once the machines are on (and in the PC case, a terminal program is connected), you should see:

pin 2 and 3 both are GREEN or flickering if data is being transmitted
all the groups of pins connected together should be RED

Now all you have to do is figure out what the data transmission rate is.

Note: searching the web seems to indicate that the company may have been bought by another company in Italy or Germany, so some telephone calls might get a manual or other information.

Good luck!

hector_carbossa - 17-1-2009 at 17:03

Hi and thanks for your support. The problem is I have DB50 connector. I attempted similar tests with device's DB9, connecting resistor-2 antiparallel leds between pins and ATX's ground or +5. Approximately you can find results in this thread.

One hypothesis I thought is DB9 isn't real terminal connector but has to be connected with a keyboard-single line display system as in article on "Rejuvenating old computerized...".

TTY?(phosphor + keyboard/printer) I saw, seems to have a "bed of nails" form of DB50 (but I have now to check better).
All particulars induced me thinking this is real system asset (n.b. a bed of nails).

In instrument's inside all 50 pins are connected to something but in addition I don't know nature of that port nor pinout for these purposes. But working old terminal shall be more satisfactory than nothing and shall light on real port nature.

Manual you stated may exist as "oral tradition" content I may try getting from today's last users (if they remember to have a phone or e-mail).

I know approximately what are DB9 and coms ports so, I tried. Now I have just this trial before planning another use for my equipment.

Thank you again.

not_important - 17-1-2009 at 21:01

50 pin? Sounds like the old Centronics 50 pin SCSI connectors

http://www.nullmodem.com/Centronics.htm

http://pinouts.ru/HD/ScsiExternalCentronics50_pinout.shtml

piracetam - 18-1-2009 at 20:00

*rubs hands*

this is a nice thread. I have one of these, with an LC Packings UZ-View (microbore) flow cell. I'd love to get this puppy to interface to my comp, I'm sure the workaround would be similar.

Attachment: AB785A.pdf (2.3MB)
This file has been downloaded 1722 times

densest - 18-1-2009 at 22:24

Well, J7 and J8 are your I/O connectors - but it's set up as RS-423, a differential signal (nominally +5 and ground) between pairs (transmit +, transmit -) to (receive +, receive -). There are kits and assembled converters for this system, but your computer RS-232 style I/O won't talk to them very well directly. The big advantage of RS-423 is it can send data for long distances at high speeds in electrically noisy environments.

A key datum is the ICs used to connect to the outside world. Older equipment uses ICs with part numbers with 1488 and 1489 in them for RS232, more recent ones use MAX232 and similar ones. Seeing a 26LS32 or similar parts implies RS422 or 423 or 485. 75xxx parts are TI's variants - I -think- 75154 is RS232.

Conversely, if all you see are ICs with part numbers starting with 74 or 80 or 82, the connector is not capable of connecting to anything for more than a few feet at most, and the interface will be entirely proprietary (one exception is a 25-pin connector with a 74LS244 and 74LS374, which is a printer port). The 50-pin connector is very likely intended to go to a switch matrix and LCD/vacuum fluorescent display like the one shown in the PDF posted here.

Hope this helps - a list of ICs near the I/O connector in question would help.

hector_carbossa - 20-1-2009 at 22:57

Hi and thank you.

All these things confirm me RS232 is for proprietary LCD/keyboard. AB's model seems to be quite similar to mine. For example, I've electronics on various extraible PCBs instead on one.
Thing to don't take light is absence of LCD/kb that may influence correct running, but at this point my purpose is trying the 50-pin hypothesis and at least, shorting RS's pins.

In RS trials my cable was about 50 cm. If possible I'll check IC's.

Naturally I've to see more accurately on AB'S manual and sparely, call some of those utilizators I stated.

At this time, main hypothesis is what I stated: 50-pins has to be connected to tube/keyboard/printer systems. Windows utilization is perhaps a chimera.

What toke me in trap was article on rejuvenation in which, 20mA loop (RS232's ancestor in my mind until now and now). In that article they have already I/O proprietary system and nonetheless, probably, a manual that resulted in correct port identification.

However, parallel port seems really to go to a printer. The problem is an eventual computer interfacing and nonetheless, a SCSI 1/ bed of 50 nails adaptor (thing I have to check as soon as possible) for TTY.

hector_carbossa - 21-1-2009 at 21:28

Unfortunately, TTY's connectors are just a little different than a DB50. They have at least over 100 pins. So, utilization I proposed outcame from an hallucinatory state, theory time has to came and eons will be passed until a first utilization even if this will happen.

I only suppose using a SCSI controller may be new direction. But may be new gamble without a program.

As final thing, I remembered I have some images online. At this time, I post them just for completeness hoping this may be interesting or useful.

Ports (bad inquadration)

Inside. Far black box on left contains all electronics as extraible, self standing cards.

At this moment I am unable to check electronics details but I hope I'll can soon.

Good bye

piracetam - 22-1-2009 at 12:54

Quote:

Originally posted by densest
Well, J7 and J8 are your I/O connectors - but it's set up as RS-423, a differential signal (nominally +5 and ground) between pairs (transmit +, transmit -) to (receive +, receive -). There are kits and assembled converters for this system, but your computer RS-232 style I/O won't talk to them very well directly. The big advantage of RS-423 is it can send data for long distances at high speeds in electrically noisy environments.

A key datum is the ICs used to connect to the outside world. Older equipment uses ICs with part numbers with 1488 and 1489 in them for RS232, more recent ones use MAX232 and similar ones. Seeing a 26LS32 or similar parts implies RS422 or 423 or 485. 75xxx parts are TI's variants - I -think- 75154 is RS232.

Conversely, if all you see are ICs with part numbers starting with 74 or 80 or 82, the connector is not capable of connecting to anything for more than a few feet at most, and the interface will be entirely proprietary (one exception is a 25-pin connector with a 74LS244 and 74LS374, which is a printer port). The 50-pin connector is very likely intended to go to a switch matrix and LCD/vacuum fluorescent display like the one shown in the PDF posted here.

Hope this helps - a list of ICs near the I/O connector in question would help.

pages 40-41 (section 1.16) reflect what you said, except that the protocols used are RS422 (rather that RS423) and RS232.
"U4 is a serial comm controller with two independent duplex channels. Channel A is used for the external serial communication. Channel B is connected to J1 (the power supply connector) for possible future use.
U34 is a dual differential line driver used for the transmit lines. Data from the U4 TXDA output is converted by U34 to two differential transmit lines, TXD+ and TXD. TXD+ can be used alone for RS232, the handshake line (HSK) is connected to the CTSA (clear-to-send) and TRXCA (transmit/receive clock) lines of U4."

hmm...it's all greek to me

[Edited on 22-1-2009 by piracetam]

not_important - 22-1-2009 at 16:12

might look here

http://www.rs485.com/rs485spec.html

http://www.arcelect.com/rs422.htm
http://www.arcelect.com/RS423.htm
http://www.arcelect.com/rs232.htm

RS423 is sort of a enhanced RS232, faster data rate and longer cables can be used.

RS422 uses similar drivers and receivers as RS423, but differentially paired so the pair of transmit data lines are swinging +/- and -/+ for ones and zeros rather than a single line going positive and negative relative to ground. If the data lines are a twisted pair, then noise rejection is enhanced.

Both RS422 and RS423 have receiver and driver specs such that up to 10 receivers may be connected to the same data lines, listening to the same transmission. For full multidrop systems RS485 is used.

What they seem be be saying is that their driver/buffer chip is used to created the differential output signal, but if you use just the TXD+ signal you can pretend it is RS232 transmit data. This usually but not always works, some attention is needed to the different ranges of voltages and currents in RS232 and RS42X.

Note that while not at all common, these serial data signal types can be used in clocked mode, where the data clock is also transmitted over the cabling. Generally this is used with synchronous data, where there are no start and stop bits.

piracetam - 22-1-2009 at 19:44

aw man..thanks.
this is somewhat reassuring. I have a 25ft. 9-pin cable (male to female)

perhaps all I need is some drivers to get it to work with LabVIEW?
i was thinking i need an DAC interface

densest - 23-1-2009 at 14:59

It's an Appletalk port. 230Kb - no wonder you couldn't see it. There are commercial and homebuilt converters for that to a PC, or you could get a very old apple

The funny mini-din (round with 8 pins) connector was the giveaway.

PLEASE for good help, post BIG CLEAR PICTURES! Without the picture it could have taken a long time to figure this one out!

And for the gentleman who started this thread - closeups of the CPU and I/O board and the wiring from the RS232 port to the boards might show something useful!

[Edited on 23-1-2009 by densest]

not_important - 24-1-2009 at 01:29

If it was doing Appletalk/lLocaltalk then it would likely have one of the Zilog SCC chips as the serial data interface (not the driver chips, but the big package connected to them). It a synchronous protocol based on HDLC, with a bit rate of 230.4 kbit/s, and ordinary UARTs aren't going to talk to it.

SFAIK the usual way to connect to a LocalTalk port using a newer Mac or a PC is to use a LocalTalk-to-Ethernet bridge or a software bridge running on a Mac that has both serial and Ethernet ports.

However:

Quote:

Spectrophotometer
The Spectracomp 602 double-beam microprocessor controlled instrument replaces the Model 601. Major features are a double optic with holographic blazed grating and an RS 232/C interface for external computing. It will be supplied with analytical programs for absorbance, transmittance and Concentration measurements.

sure implies that it's an ordinary RS232/RS422 port. Looking at the photo from above it appears that the mini-DIN and DB9 share at least some signal lines, perhaps it could operate in either mode?

[Edited on 24-1-2009 by not_important]

hector_carbossa - 24-1-2009 at 03:06

I'm not sure I have found AB's manual defining ports usage in a manner that may be revelatory. As mine, your DB9 has small number of pins but may be intended for different utilization. On the other hand, manual seems quite clair on this. Have you ever done any sort of test?

Densest, unfortunately, in my old "album" there's not some representing each standalone extracted pcbs.

I'm pleasured deep interest come out and, as gentleman, I have to satisfy it. On the other hand, everyone interested, me included, shall wait just a little (while I find functional camera) to see more appropriated pictures on this thread.

In meantime, there's an introduction on SP602's inside world, hoping to calm down your knowledge thirstness and nonetheless, mine.

Cylinder on left, may be gas pump. On right, there's parallel(?!?) port hidding serial which has wired only upper pins. All wires converges in farthest, middle-left black box which contains pcbs. Nearest gray, black topped box contains opticals. On it's right, sample room and detectors. Always on right, rough power supply.

Splitted in two cards panel.

A thing to underline is setting focus on exact wires source perhaps may be difficult even if I "dismantle" instrument.

For all remaining things, I am not a field operator and I haven't new, good ideas. At this moment I'm not sure on my "small I/O" theory and when I look, at school, at greyish instruments wired to green phosphor, no one can say from where those setups come from.

A thing, I stupidly think about, is that in 80's may was another way to underline part missing. Missing deuterium lamp may feedback something on circuitry.

Quote:

However: Quota: Spectrophotometer The Spectracomp 602 double-beam microprocessor controlled instrument replaces the Model 601. Major features are a double optic with holographic blazed grating and an RS 232/C interface for external computing. It will be supplied with analytical programs for absorbance, transmittance and Concentration measurements. sure implies that it's an ordinary RS232/RS422 port. Looking at the photo from above it appears that the mini-DIN and DB9 share at least some signal lines, perhaps it could operate in either mode?

I read that review. In effects, the analytical program may be also a communication program. Upon now, problem remained: program is integrated in instrument or is supplied as 5 inches floppy disk? Perhaps only persistent users may answer to this question. Probably this will be categorically THE direction. Thanks.

[Modificato il 24-1-2009 da hector_carbossa]

densest - 24-1-2009 at 09:10

It's possible that piracetam's machine can run in either mode, but the round connector is the one used for appletalk, the pins are connected as appletalk requires, the serial communications chip is a 82530 which Intel asserts is capable of handling "virtually any serial data transfer application", the usual handshaking signals are absent, the two connectors are daisy-chained for a bus architecture, and the pins on the DB-9 are not in the usual places for a RS-232 connection. IF the machine is capable of being run in an RS-232 mode it would need a special cable: one that carries data from the instrument on pin 4, to the instrument on pin 8, signal ground on 1 or 3, and needs pin 7 grounded (short 7 to 1 or 3).

I think Mr. Carbossa's machine is using something approximating regular RS-232 connection - a session with a voltmeter might confirm this.