KEITHLEY 175 (w/ 1753) GPIB Communication Issues

[Sharpect]

Hello,

I recently purchased an older Keithley 175 DMM in an attempt to use it with LabView via GPIB. I've tried for a few days to detect it on NI MAX but have been unsuccessful, I've tried sending commands on NI VISA but that hasn't had any success either. I've successfully managed GPIB comm with Keithley 2000/2001s, quite easily, but these units are at my job so I can't use them at home for personal use. I started to suspect that maybe the 175 is too old to use with newer NI GPIB software, so I connected one of the older teslameters. But sure enough that was found, so I don't think age or software is the issue. That isn't a great test but it's all I could think of. The multimeter does show "RMT" on the display which indicates the 1753 module is controlling the dmm so I at least think the module is detecting that a GPIB is connected. 

I've gone through the 1753 GPIB module manual a bit to try and troubleshoot, and while it has good info about potential commands etc. a lot of the examples are for sending commands from an HP-85 which I don't think is applicable anymore. If anyone has any suggestions on things to try, they would be welcome.

[cstorey]

Your Keithley 175+1753 is early 1980/1990s tech.  But if it measures correctly manually and the RMT light comes on, it seems to be talking to the bus and probably still works fine.  It will never be recognized in MAX automatically since it doesn't support the IEEE 488 standard commands.  But that's fine, it should still work if you send it the right commands and termination characters.

I've never used the 1753a IEEE interface with a 175a, but I've used a lot of Keithley's from the next generation.  Here's my advice..

- make sure the GPIB address is set and you know what it is and doesn't conflict with anything else you have connected.  Addresses should be separated by 2 (i.e. instrument #1 = 6, instrument #2 = 8).

- Look at those old HP-85 examples and learn what commands need to be sent to setup the measurement conditions you need. (They had great detailed examples and programs with good descriptions back then!)  The commands are probably 2 character commands like "R1" or "V3".  Some of my older Keithley have a command sheet glued to the top for easy reference. The manuals should have a table and description of each command as well.  There will also be a section on reading data and what the expected read and write termination characters are supposed to be.

Once you know the handful of commands needed to setup the instrument, write code or use MAX to test send commands and reading data.  Pay attention to the right termination characters and EOI setting required.  (i..e. RTFM for the 1753 and do as it says 🙂

Best of luck!

Craig

[Minions]

My suggestion here would be to try a simple communication through Max (Open VISA Test Panel then select the Input/Output tab).

Now, enter id?\n in place of the *IDN?\n.  Press the Query button.

If you get a failure, then it requires the even earlier 2-character entries, but if it works, you will need to get the pre-SCPI commands for IEEE-488.1 control.