Author Topic: My Keithley 196 is on its way... (Here she is, lots of pictures)  (Read 15481 times)

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Offline JBeale

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Re: My Keithley 196 is on its way... (Here she is, lots of pictures)
« Reply #25 on: August 07, 2014, 11:13:40 pm »
Sorry for the delay, haven't been on the board for awhile... sadly my 196 has broken down. But I was using this USB-GPIB adaptor: http://galvant.ca/shop/gpibusb/
actually he's now selling rev.4, what I have is rev.2 but I think it is similar.
 

Offline idpromnut

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Re: My Keithley 196 is on its way... (Here she is, lots of pictures)
« Reply #26 on: August 08, 2014, 03:05:45 am »
I love my 196! I think it will make you a very happy camper! (@cellularmitosis:I guess you're the one that got the 196 I had in my watch list on fleabay ;)
 

Offline David Hess

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Re: My Keithley 196 is on its way... (Here she is, lots of pictures)
« Reply #27 on: August 08, 2014, 06:22:43 pm »
Apart from certain MOSTEK EEPROMs (used in some HP and Tek products like the HP 3456A) that had manufacturing defects, EEPROMs generally seem to last a very long time. I'm sure there is a small chance for them to fail, but it's not like EEPROMs in instruments from the late eighties are failing in droves.

I believe those were MOSTEK mask ROMs and not any sort of PROM, EPROM, or EEPROM.
 

Offline JBeale

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Re: My Keithley 196 is on its way... (Here she is, lots of pictures)
« Reply #28 on: August 08, 2014, 11:55:12 pm »
To answer your question about code to read GPIB from a PC, I use Python to do that. I wrote about it here http://dangerousprototypes.com/forum/viewtopic.php?f=2&t=3769&start=30#p47437 but to save you the trouble, copied below. You would at a minimum need to change the serial port number to match whatever COM port the GPIB-USB adaptor ends up being on your system.

Code: [Select]
# Python 2.7 code to get readings from Keithley 196 multimeter via GPIB
 # Assumes meter is already set up to correct mode, eg. from front panel
 # Dec. 17 2012 J.Beale

from __future__ import print_function   # to use print without newline
from serial import *
import time,datetime

cmd = "?\r"            # GPIB command to Keithley 196 must end with carriage return
eol_str = "\n"  # end of line string in file output
buffer =''           # serial input buffer
outbuf = ''          # file output buffer

ser=Serial(17,460800,8,'N',1,timeout=1)  # GPIB-USB board on COM18, with 460800 bps, 8-N-1
f = open('K196-log.csv', 'w')
print ("Keithley 196 log v0.1 Dec.17 2012 JPB")
f.write ("date_time,volts\n")
f.write ("# Keithley 196 log v0.1 Dec.17 2012 JPB\n")

while True:
    ser.read(255)            # clear out existing buffer & throw it away
    ser.write(cmd)                 # send query to instrument
    buf = ser.readline()         # string terminated with '\n'
    buffer = buf.split()[0]   # get rid of the \r\n characters at the end
    outbuf = str(datetime.datetime.now()) + ',' + buffer
    print (outbuf)
    f.write (outbuf)
    f.write (eol_str)
    time.sleep(9)                        # from 'time' to wait this many seconds
   
f.close                  # close log file
ser.close()            # close serial port when done. If we ever are...

Example output:
Code: [Select]
    date_time,volts
    # Keithley 196 log v0.1 Dec.17 2012 JPB
    2012-12-17 13:25:18.006000,+10.00400E+0
    2012-12-17 13:25:28.115000,+10.00401E+0
    2012-12-17 13:25:38.147000,+10.00400E+0
    2012-12-17 13:25:48.225000,+10.00400E+0
    2012-12-17 13:25:58.256000,+10.00400E+0
    2012-12-17 13:26:08.365000,+10.00401E+0
    2012-12-17 13:26:18.396000,+10.00400E+0
« Last Edit: August 08, 2014, 11:58:39 pm by JBeale »
 
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Offline coromonadalix

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Re: My Keithley 196 is on its way... (Here she is, lots of pictures)
« Reply #29 on: December 07, 2018, 03:57:56 am »
The Keithley 196 analog board is almost 90-95% identical to the Tektronix DM5120, the 5120 has optocouplers  vs the 196 has isolation transformers

The logic board is very different, simpler design in the Tektronix DM5120
 

Offline cncjerry

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Re: My Keithley 196 is on its way... (Here she is, lots of pictures)
« Reply #30 on: December 08, 2018, 04:47:37 am »
I've had a 196 for a while and like the meter but it needs to be warmed up more so than others I own. I wouldn't calibrate it until you warmed it up for several hours. Large, bright display.   Mine seems pretty stable with repeatable accuracy over 4 months.

I also have a 195a and a 199.  The 196 is clearly the better of all of them.

Jerry
 


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