Synchronization of TDS 5104 and a multimeter

Question

Hi all,
I am using a TDS 5104 DPO and a Keithley 2001 digital multimeter (DMM) to capture a pulse signal.
I use a GPIB bus trig command to initiate the DMM and a acquisition setting vi (tktds5k_SetAcquisitionState.vi)
provided by the Tek to start the measurement by the DPO. The record in DPO is lagged than that of
the DMM. Any suggestions to make the instruments to start at the same time?
Thanks a lot for your help!
sucon

Answer 1

Sucon,
It sounds like you are using the instrument driver for the TDS 5104 DPO. There is also a driver for the Keithley 2001 digital multimeter. You can find these LabVIEW drivers here. I would look through the example VI's that are included in these drivers to see if there is any way you can trigger the instruments at the same time. In the TDS 5104 driver there is a triggering folder found in tkds5000>>Configure>>Trigger, there might be something useful in here.
Also, there is an example VI called "Basic Level Triggering of Waveforms" that you can find in the NI Example Finder. To launch this go to Help>>Find Examples, then go to the search tab and type in "Triggering", this example should be one of the first ones that shows up. If you look at the block diagram of this VI there is a "Basic Level Trigger Detection.vi". Here is the description for this vi:
Finds the first level-crossing location in a waveform. You can retrieve the trigger location as an index or as a time. The trigger conditions are specified in terms of threshold level, slope, and hysteresis. You can use this polymorphic VI to perform trigger detection on a waveform or an array of waveforms. The data type you wire to the signal in input determines the polymorphic instance to use.
Please repost if you have more questions.
JenK