Keithley 2400 Trigger 2000

Question

Hi,
I have tried for a couple of days to let a Keithley 2400 source current and measure voltage and at the same time trigger a DMM2000 on which a current will be measured. This is for use in a LIV characterization. I�m using Labview but prefer to write directly to the bus instead of using the Labview drivers, which I find a bit complicated to use.
First I configure the 2400 with the following commands
*RST;
TRAC:CLE;
SOUR:FUNC:MODE CURR;
SOURWEPAC LIN;
SOUR:CURRTAR 0;
SOUR:CURRTOP 0.1;
SOUR:CURRTEP 0.0001;
TRIG:COUN 100;
SOUR:CURR:MODE SWE;
SENS:FUNC "VOLT";
FORM:ELEM CURR,VOLT;
TRIGOUR TLINK;
TRIG:INP SOUR;
TRIGUTP SENS;
Then I write the following to the DMM 2000 to initialize
*RST;
TRAC:CLE;
SE
NS:FUNC "CURR";
TRIGOUR EXT;
TRIG:COUN 100;
Now the two instruments should trigger each other.
I then write to the 2400 to turn on and initiate the sweep.
OUTP ON;
INIT;
And finally an INIT is sent to the DMM2000 to initiate this instrument
This starts the measurement ONLY if the instruments have been turned on just before the program is executed.
If I run the full program again it doesn�t start. What is wrong?
If I run the program from the initialization of the 2000 it works well. But if the intialization of the 2400 is included it just wont start the sweep.
Any suggestions?
Regards
Francis

Answer 1

You may wish to try this. I struggled with a 2400 for some time. After a single reading, the buffer in the 2400 contains current, voltage, ohms, a timestamp and another variable. You have to read the entire buffer of the 2400 or it ignors future commands. I struggled with the 2400 drivers also. The help files of the drivers did not describe one of the variable inputs. Finally, I figured out that it was leaving data in the buffer. I increased the variable to read all five values and it finally worked!
You will have a different solution because you are not using the drivers. But I suspect you may have the same problem. You will have to write commands to be certain you extract all measurment information for the reading. Perhaps the DMM may also have a simi
lar feature. If you do not read all the data, the systems will hang.