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2 Power Supplies: Increment Voltage on one while checking Current on the other ???

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Ok, so I am working with 2 Agilent E364X Power Supplies. I have a device with a gate and drain that I am applying power to. With the Gate I am applying 1.5V & .3A current  limit , the drain I am applying 9.5V & 1A current limit. What I am trying to do is step up the gate voltage while monitoring the Drain current, and need the increments to stop when the Drain Current gets down to .5A +/-50mA. I guess I kind of have two issues. I am using a state machine, the first iteratino sets both of the PS's to the desired settings (works fine), next iteration is supposed to step up the Gate Power Supply's Voltate with small increments, check the Drains Power Supply's Current reading to see if it falls in the given range, if not the continue incrementing, recheck, and so on... I am having an issue with the increment part as well as the checking the for the Current part. I was thinking maybe I need to use a Flat Sequence or something along that line. Any help would be greatly apprecaited

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It would be extremely helpful if you could describe the symptoms.

Bill
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When I run the VI, its starts fine ... When I press Set Voltage both of the power supplies adjust to the mentioned settings (as wanted), When I press Increase Voltage the Gate Power Supply screen flashes Output Off and then reads 1.51V & 8.00A, the Drain Power Supply reads Current Vari and sets to -0.00V & 0.00A.

 

What I need to happen is, press Increase Voltage and both of the power supplies stay running, and the Gate Power Supply increase with a 0.01V increment, check the current on the Drain power supply, if it falls within the .500A +/- 50mA, then stop, if it doesnt read withing that window, to increase with another .01V and recheck, continuting this until it falls withing the desired amperage.

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Message 3 of 10
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Is there a reason you are initializing each power supply with every staet change?  Normally you do that once, at the begining of thet est.  Initializing the power supply would, indeed, turn off the outputs.

Bill
CLD
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Proud to say that I've progressed beyond knowing just enough to be dangerous. I now know enough to know that I have no clue about anything at all.
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Message 4 of 10
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I have fixed that already

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Message 5 of 10
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So... what does your current VI look like?  I have some ideas, but I can't really say until I see it.

Bill
CLD
(Mid-Level minion.)
My support system ensures that I don't look totally incompetent.
Proud to say that I've progressed beyond knowing just enough to be dangerous. I now know enough to know that I have no clue about anything at all.
Humble author of the CLAD Nugget.
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Ok, sorry I've done some changes since original post ... What I did was remove the Close from Process 1 and the Initialize from Process 2 ... New results are as follows ...

 

Set Voltage sets both the Gate Power Supply & Drain Power Supply to 1.5V .3 A & 2V 1A, respectively. Press Increase Voltage, Gate Power Supply increases to 1.51V & Drain Power Supply Current reads .198A, and then it stops processing.

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Message 7 of 10
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You have a major issue in Process 2 state.  If the read current was less than 0.5, then you will be stuck in an endless While loop.  You need to put the reading of the current and the setting of the voltage inside of the While loop if you actually want them to change.


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Thank yoiu CrossRulz, So I came up with this, I think this is what you were referring to, it properly changes the voltage as desired. Just not sure if I should close the multimeter VI following results. Also I was curious as to if this should be done with Flat Sequence or if its simpler to just leave it as is. I am pretty new to labview and dont necessarily know the best programming techniques yet. Any other advice is always welcome. Thanks again.

 

SetVoltage.jpg

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Accepted by topic author gingram536

For supply #1, you should just have the setting of the voltage itself inside of the loop.    It probably wouldn't hurt to through an extra checking for errors just in case (you can then abort if there is an error).  The rest can probably stay outside of the loop.


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