Array 3646A power supply problem

[Goy88888]

Hi,

I cannot get Array 3646A power supply to update voltage continuously with triggering enable/disable output, I have looked at the Vi's that are provided by this website but, the program only works as a one time command. My purpose is to hook this PS with a PID loop to a temperature controlled heater, so I need the Voltage to be varied based on a sensor and updated as needed. Is there a way around the enable/disable output command or is there a separate labview program that can change the settings on the fly rather than the current start and stop. 

http://sine.ni.com/apps/utf8/niid_web_display.download_page?p_id_guid=A40AB1DAFDB64F6CE0440021287E6A...

Thank you very much!!

[johnsold]

The example does not do much, but if you look at the VIs in the Public folder, you will find all the pieces you need to do what you want.  It is somewhat confusingly named, but the Configure Power Supply Operating Parameters.vi sets the output voltage.

Lynn

[Goy88888]

Thanks, for the quick reply,

The examples dont match but I did get it to work as the models are quite similar. I can configure the power supply parameters with no problem, as well as putting the main VI in a while loop and updating the voltage as necessary, but the problem lies in the enable power supply.vi or the associated write command.vi. As there is a condititon that tiggers the PS to flicker on/off repeatedly. For example, Set the Volt, turn on PS, the output reaches the set limit, goes to 0 volts, and then hits the limit again and repeats. I cannot figure out a way to set and enable output with it turning off. If you need any images or copies of the VI, please let me know.

Thank you!

http://forums.ni.com/ni/attachments/ni/140/50880/1/write%20command.png

http://www.array.sh/download/Communication%20protocol%20for%20power%20supply.pdf

[johnsold]

Are you saying that you configure the outputs, enable the output, and then the voltage climbs up to the maximum limit and shuts down?

Does it do this when operated manually?

What limits and set voltage are you using?  What is the load on the power supply?

Lynn

[Goy88888]

Manually it is fine and using the in-house program from the manufacture it runs perfectly with the 200 Watt, 120V tape heater it is fine. It is not hitting the maximum limit, it is just hitting the set limit and then turning itself off and on again. So there is nothing wrong with the limits of the PS, the issues arises from the output switching on/off.

So an example would be

Set the voltage to 8V within the Labview program,

Turn it on and PS outputs 8V and 0.14A for a fraction of a second (enable power supply goes on with turning on the program)

Then the enable power supply.vi gets triggered again, output shuts off not sure why it doesnt stay on (enable power supply goes off)

enable power supply.vi gets triggered for a third time, resulting in turning the output back on, and it cycles repeatedly. 

Ideally, when the program turns on, the PS should automatically enable output and stay on without it cycling on/off.

I hope this helps.

[johnsold · Accepted solution]

The reason it shuts off is that you are telling it to do so.  Look at what your program does: It initializes the power supply.  Initializing sends a command 82h with the data value 02. This sets the power supply to remote control with the output OFF! Then you turn the output on.  Next you set the voltage to the desired value.  Immediately after this, the while loop iterates and the power supply is reset again.

1. Do not set  a while loop to run forever.  Do not use the Abort button in the toolbar to stop your VI.  It is an escape hatch for use during development in case a program is not working correctly.  Put a Stop button on your front panel and use that the stop the loop.

2. Do not use seqeuence structures when not needed.  Your program will work exactly the same without it.  LabVIEW uses dataflow to determine which part of the program will execute next.

3. You should learn about state machines.  They give you much flexibility to do the kinds of things you are trying to do.

4. Until you have learned how to use a state machine, move the Initialize and Enable Power spuuly VIs outside the loop.  They only need to run once.  Put the configure VI inside the loop.  Also put a Wait (ms) function inside the loop.  The loop does not need to try to run hundreds or thousands of times per second.  (A better approach would be to use an Event structure and only send new data to thepwer supply when the Value of Voltage Level is changed.)

5. After the loop put an Enable Power Supply VI with the input set to disable the output, followed by a Close VI.  This is similar to the example program.

Lynn

[TBN]

I have a similar problem with the example "Array Electronics 3600 Series Output DC Volts.vi"

It set the output to off when I running it, if I change the command 82h data value 02 to 03 its set the output to on, when I stopping the vi.

I am trying to do the same, to control a heater with a PID, so I need change the voltage output.

Thanks in advance

[cody_a]

TBN,

Have you tried the steps johnsold recommended?

[TBN]

I got it to work by setting a delay into the initialization