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Products => Test Equipment => Topic started by: ivaylo on July 11, 2014, 06:20:59 am

Title: Reading from Keithley 2015 via serial RS232
Post by: ivaylo on July 11, 2014, 06:20:59 am

The beast clearly listens but does not respond. I am using an USB to serial converter (tried two of them, a good FTDI based and another one which I know also works), my serial settings are like the book says (9600, bytesize=8, parity=none, stopbits=1). The instrument has RS232 enabled and all matching settings. Same results under Ubuntu (Python and some terminal program) and Win7 (Putty).

This is how I know it listens:
 - every time I send "func 'volt:dc';:read?" and the instrument triggers and freezes the display with the given voltage ('REM' lights up on the display)
 - "*RST" consistently resets it (clears the screen with "-------")

No command returns anything back though, tried "func 'volt:dc';:read?", "*IDN?", etc.

I am either missing something obvious or the instrument is broken or something. Decided to ask before I start listening to cables and such. Appreciate your help...

Title: Re: Reading from Keithley 2015 via serial RS232
Post by: AndyC_772 on July 11, 2014, 06:28:38 am

I had much the same with my 2000 meter. Turned out the RS232 level shifter IC in the unit was dead, so although the meter could receive serial OK, responses never made it out of the port.

Check the voltage levels on the serial port with the PC cable plugged in, and make sure the meter can drive the PC's RXD line to valid levels.

Title: Re: Reading from Keithley 2015 via serial RS232
Post by: ivaylo on July 11, 2014, 08:42:16 pm

GPIB works fine, decided to postpone the Serial investigation...  :-//