DMM 34401A- how to use external trigger asynchronously.

[lvrat]

Hello,

I am using DMM 34401A (GPIB) instrument and power supply 6834 (GPIB).

The setup is:

1. DMM external trigger connected to relay

2. Configure the power supply and start ramping the voltage.

3. Configure and arm the DMM to wait for external trigger.  -> at this point when DMM is at Fetch function, it blocks the supply therefore the voltage stop ramping. It starts ramping again when DMM has finish execution (i.e. either trigger received or timed out).

My question is how can I use DMM EXT trigger asynchronously so it does not stop the power supply voltage or frequency ramping?

TIA!!

[santo_13]

You've not described enough about the use of 6834 power supply?

Based on your description, I would assume that the 6834 is ramping on its own without any external control, why would it stop because DMM is waiting for a trigger?

Please provide more details on what you intend to do and how things are connected together.

[lvrat]

Hello,

I have a VI to ramp the AC voltage or frequency of 6834 every 2 secs (see attached). Ramp Init. Value subVI is using Min/Max function to identify if user send the increment value at +2 (ramp up) or -2 (ramp down). False case is for Ramp Up so it checks for "less than" value.

Although I am curious to find how can I set 6834 to ramp on its own and not use subVI to Ramp the AC volt/freq, please point me to any resource you know.  

That maybe a way to try to see if DMM trigger will not block supply. 

DMM trigger channel is connected to scope channel 2 and they are both connected to relay #x to UUT. PS is also connected to UUT. When the relay toggles the trigger is received on DMM and I need to capture the respective volt or frequency. 

Thank you.

[santo_13]

I didn't know anything about your supply during the last post, but lucky me, my assumption was right, your supply has a List mode where it can go over a sequence of precisely timed and synchronized steps

This way, you can program the supply to do everything on its own without any software interaction, leaving the GPIB free for your DMM automation, btw, your DMM should also be advanced enough to automatically capture and store the measurements (if configured appropriately), once all the sweep steps are done, you can retrieve all the measurements at once.

I have never used the 34401A or 6834, I am simply going by my experience with other typical instruments in the market and assuming that these few thousand USD instruments must be capable of and to the surprise, they may or may not be capable of.

As and when you have a question, I refer to the respective available documentation online to point you in the right direction, beyond that I don't know all the tricks required to get it working.