SR245

[yk]

I am using the SR245 VI of the Stanford Research A/D converter downloaded from the NI's website. I succeeded to see the graph data after scanning and ramping the channel 4 and 8 simultaneously from the SR245 example.vi by using the Labveiw6.1 with the external trigger inserted in the digital channel 1. But I want to do the experiments with using the internal trigger mode asymp???. Can I do that in SR245.vi?
I could do the 230 times SCAN for the ramping the data. But, I would like to do the SCANNING much more times. When I changed the scan number to 1000, the error showed. How can I solve it? Or, can I replace the ramping channel from 8 to 2 in the SR245.vi? Please show me how to modify the existing SR245.vi and the example files.

[Sastry V.]

Hello,

What type of error are you getting? Also what is the maximum scan rate specs of the device that you are using? If it is interval sampling, then you should check if 1000*number of channels is within the sampling rate specs of the device.

Please do let me know if you have any questions.
Also please do let me know the exact error that you are getting. That will give me some insight.

Sincerely,
Sastry V
Applications Engineer
National Instruments

[yk]

Thank you for your kind assistance:

I�ve found I can do the scanning much more times (more than 3000 times at channel 1 of the Stanford Research SR245 interface) when I raise the sampling rate.
However, I still encounter the error when the scanning time exceeds about 10 second at any sampling rate. When I start the scan with the SR250 Integrator/Averager.vi, the green ramp turns 'ON' on the SR245 device interface and keeps accumulating. But, the red error ramp gets active after the 10 second scanning. I would like to do the sampling much more than several minutes. Is it the problem of the external trigger input plugged in the digital 1 channel? Or the SR245 is broken?

Sincerely,
Yasuhiro K
Chemistry Researcher

[Sastry V.]

Hi,
I think this is happening because of some overflow error that usually happens when you have limited buffer size. Please try to increase the buffer size and see if it helps. You should be able to set the buffer size from the front panel itself.

Please do let me know if the problem still persists.

Sincerely,
Sastry V.
Applications Engineer
National Instruments

[yk]

Thank you.

Where can I find the buffer size setting? Is it at the pannel of the SR245 interface itself? Or some VI pannel of SR245 shown from the Labveiw?

Regards,
Yasuhiro K.

[Sastry V.]

Should be on VI front panel.

[yk]

Is it SR245.vi?

[yk]

I cannot find out the setting of the buffer size, yet.
Could you please show me what name of the vi file?

[yk]

I found existing SR245 interface is too old (product of 1987) to be read by the PCI-GPIB.
So I think a 270 pF
capacitor must be placed between pin 10
(ground) and pin 17 (DAC) on the GPIB bus
driver according to the suggestion described in http://exchange.ni.com/servlet/ProcessRequest?RHIVEID=101&RPAGEID=135&HOID=506500000008000000CB0A0000&UCATEGORY_0=_26_%24_13_&UCATEGORY_S=0&USEARCHCONTEXT_QUESTION_0=SR245&USEARCHCONTEXT_QUESTION_S=0
I think I have to modify the interface. So first, I will try it.

Thank you.
Yasuhiro K.

[yk]

A 270 pF capacitor has been placed beteen pin 10 and pin 17 for SR245. But the problem is not fixed at all. Again, please show me the details of setting of the buffer size in the Labview6.1. Where can I find the setting of the buffer size.