Keithley 2700 only responds to GPIB ch 1 - Page 1
Forum section: electronics / testgear

author: rx8pilot
author_rank: Super Contributor
timestamp: September 22, 2015, 05:56:58 pm
content: Hi all,I recently purchased a Keithley 2700 DMM with a 20 channel multiplexer for both bench work and automated test. It has been a great choice so far as it's regular DMM functions. The trouble I cannot figure out is that it only seems to respond to channel 1 in the GPIB port. Not sure if it is damaged or user error. So far I have gone through the manual, Google, keithley forum, and a couple hours of hacking without success. It seems to communicate fine on ch 1 but any other channel there is no response at all. This is all through the National Instruments VISA utilities.As a side topic, I cannot get LabView to connect to it either. To be fair, LabView, GPIB, and automation are all new to me so it could be a simple thing. I have been successful in getting 2 power supplies, 3 DC loads, and a scope connected and working so far on the same system.LabView 2015Tektronix AD007 VXI-GPIB controllerCan anyone make a suggestion where to look? Maybe I am missing the basics and need a tutorial?

author: eas
author_rank: Frequent Contributor
timestamp: September 22, 2015, 10:24:34 pm
content: When you change the GPIB address from the front panel, what happens? How does the instrument respond? Is the setting still correct when you go back and check it?What firmware version does the 2700 have? What versions of the the Keithley I/O layer are you using? What version of the driver for the USB/GPIB adapter?

author: rx8pilot
author_rank: Super Contributor
timestamp: September 22, 2015, 11:25:14 pm
content: Quote from: eas on September 22, 2015, 10:24:34 pmIt does indeed save the settings when GPIB config is changed on front panel. When it is in channel 1 and I scan the GPIB bus with *IDN it responds and ID's itself. When set for any other number it does not respond on the bus. I did manage to force data to it with NI Measurement and Automation Explorer (MAX) so I guess the Keithley is not dead. Looking more like a software thing than hardware but I am such a newbie in automation, GPIB, VXI-11, LabView, etc. it is hard to know where to look.2700 Firmware is the latest Keithley has: B09What is the 'IO Layer'? Is that the LabView drivers?LabView drivers are 2.3 and I verified there is nothing newer.The GPIB adapter is VXI-11 to GPIB (Ethernet) so it does not have it's own drivers. It is connected to the LAN and is working with all the other instruments.

author: eas
author_rank: Frequent Contributor
timestamp: September 23, 2015, 12:09:17 am
content: Sorry, I glossed over the fact that your GPIB adapter is a VXI-11 bridge. I think the Keithley I/O layer is a bundle of their IVI driver, and various runtimes and libraries and utilities. The same bases are probably covered by the LabView install + the LabView driver.When you try to communicate with the K2700, what are you using to communicate with it? When you say you force data to it using MAX, do you mean you can get a response via MAX when the Keithley is on something other than GPIB #1?When you change the address using the front panel. How are you telling your software on the PC to use a new address? I ask, because when I was first mucking around with talking to my Keithley's via VISA I kept forgetting I needed to use a configuration utility to change the GPIB address for the virtual instrument and then save that config change.

author: rx8pilot
author_rank: Super Contributor
timestamp: September 23, 2015, 12:48:27 am
content: Quote from: eas on September 23, 2015, 12:09:17 amI was just doing a scan of the GPIB bus and the active instruments ID themselves - pretty much plug and play. The Keithley works this way, but only when it is on channel #1. Inside of the NI MAX utility, I was able to tell it to specifically look on (for example) channel 7 for the K2700. That seems to work in getting it connected to LabView but it still does not show up in the GPIB list. If the channel is changed, I have to remember to go and change the settings just for the Keithly and there is no way to look at the GPIB list of connected devices and know it's working.There are so many disjointed little pieces of LabView. I am struggling to figure out how they are all related. Overall, the power of LabView seems to be worth the setup fuss, but it's not exactly an elegant experience. Crazy when you look at how long they have been doing it.Anyway....all the other instruments connected right away with no challenges at all. If the Keithley is the only one with trouble, it's not so bad.