keithley 2182A: Continues dc measurement

[Enrique]

Hi,

Is it possible to program the 2182A to perform a number of DC measurements ( let say 20) and then recover the measurements from the buffer. I would like to configure the machine for doing the measurements and later recover them instead of doing individual measurement/reading.

In the manual is written:

:TRAC:POIN 20 Set buffer size to 20.
:TRAC:FEED SENS Set to store raw readings.
:TRAC:FEED:CONT NEXT Start storing readings.
:TRAC:DATA? Request all stored readings.

Does it mean that the 2182A is going to perform 20 measurements? Or does it simply save the next 20 measurements in memory?

Thanks

[Dale C]

One more command is required.
Place :INIT between
:TRAC:FEED:CONT NEXT
and
:TRACE:DATA?

The :INIT will start the data taking process.
Then the Model 2182A will take 20 readings and store them in the buffer when the :INIT command is received.
Then :TRACE:DATA?
will retrieve the 20 readings when the 2182A is addressed to talk.

[Enrique]

Shall I introduce a delay between :INIT and :TRACE:DATA?. to let some time to the 2182A to take the measurements?

Thanks

[Dale C]

Yes. That would be a good idea.
The amount of delay depends on how the 2182A reading rate is congfigured.

[Enrique]

Hello,

I have followed the indications and I have add the command “INIT”. However I do not get any response from the device.

I have moved to the VIs provided by Keithley but I could not make it work. I did proceed as follow:

Frame1:

Measurement mode VI (Selected chanel 1)
DCV config VI (default values except NLPC=0.1)
Buffer Config VI------- Here I have modified the VI. In the original VI is written “:Trac:Feed:Cont Next;” and I change it by “:Trac:Feed Sens;:Trac:Feed:Cont Next;” (Options: Configure Buffer, Next and 5 Points)
Initiate/Abort VI (Option: Init One cycle)

Frame2:
Delay of 20 seconds To be sure that the machine can take the readings.

Frame3:
Buffer Read VI


Right now, I don’t know what I am doing wrong. Could you give me any indication.

Thanks

[Dale C]

Try these SCPI command codes.
*RST
:TRACE:CLEAR
:SAMPLE:COUNT 20
:TRACE:POINTS 20
:TRACE:FEED SENS
:TRACE:FEED:CONT NEXT
:INIT
Wait about 6 or 7 seconds for it complete.
:TRACE:DATA?
Now read the data.

[Enrique]

Thank you it works perfect.

It was missing :SAMPLE:COUNT 20 command

[SHENBAGA PRIYA T]

Hi,

I am need to load 1000 data with the trigger and read the data stored in Trace by initiating it. I followed the steps given here (in the previous posts). But I could not read more than 60 data from the buffer. The scenario is, when I set the Sample count >60 (say 100) and the Trace Store points as 100, I end up with Timeout error (even with delay set to 20s) and could not read. Instead if I try to set the Trace Store Points<=60, I am able to read the 60 values form the buffer.

Can anyone please help me and let me know where I am going wrong and get the data read from the buffer?

Thanks in Advance.

Regards,
Shenbaga Priya

[Dale C]

Try this code.
*RST
:TRACE:CLEAR
:VOLT:NPLC 0.01
:SAMPLE:COUNT 1000
:TRACE:POINTS 1000
:TRACE:FEED SENS
:TRACE:FEED:CONT NEXT
:INIT
Wait about 20 seconds for it complete.
:TRACE:DATA?
Now read the data.
This worked fine in my Labview 2012 program.
Maybe in your program the timeout setting is not set long enough?

[SHENBAGA PRIYA T]

Hi Dale C,

Thanks for the response. I tried both in LabVIEW 2010 and 2012 with timeout configured for more than 30s. The measurement delay is also configured 25s.
I am ending in timeout error. How can I ensure that the the trigger operation is complete. Can using OPC query be helpful in this case? Or I could try with
:INIT
Wait for 30s
:ABORt
:TRAC:DATA?

Thanks in advance.

Regards,
Shenbaga Priya

[Dale C]

You could do *OPC to do this.
You could put in a hard delay, like you show below.
You could have the unit SRQ on buffer full.
Either method would do it.
Most users like the SRQ on buffer full.
Just send :STAT:MEAS:ENAB 512 for Buffer full
and *SRE 1
Then have your program wait for an SRQ.
That should do it.