gpib multichannel device control time delays

[ddelanauze]

Hi,

I'm am working on an GUI application written in C# to control multiple power supplies (6 in total) with a NI GPIB-USB-HS.

The first power supply is connected via the gpib interface, while the rest are connected in a serial pattern using RJ45 cables.

In my C# application, I use the following command line to initialize only the first power supply:

device = new Device(boardNumber, primaryAddress, secondaryAddress);

where boardNumber = 0, primaryAddress = 1, secondaryAddress = 0.

When I use the following multichannel SCPI command to turn on (or off) the power supplies, the power supplies respond immediately (31 ms according to the compiler).

device.write(ReplaceCommonEscapeSequences("OUTPUT1,2,3,4,5,6:POWER ON\n"));

Unfortunately, when I try to set different currents on each power supply using sequential SCPI commands, the compiler finishes transmitting the commands around 31 ms later, but the outputs of the power supply aren't completely changed until about 3 seconds later! 

For example:

device.write(ReplaceCommonEscapeSequences("SOUR1:CURR 15\n"));
device.write(ReplaceCommonEscapeSequences("SOUR2:CURR 20\n"));
device.write(ReplaceCommonEscapeSequences("SOUR3:CURR 25\n"));
device.write(ReplaceCommonEscapeSequences("SOUR4:CURR 30\n"));
device.write(ReplaceCommonEscapeSequences("SOUR5:CURR 35\n"));
device.write(ReplaceCommonEscapeSequences("SOUR6:CURR 40\n"));

I was wondering if anybody experienced this same problem? And if so, is there a way to speed up the process in order to be able to refresh the outputs of each power supply more rapidly?

The problem seems to be in the GPIB mutlichannel communication.

Any help would be greatly appreciated!!

Thank you,

Dominic

[Jensen W]

It seems like the commands are getting sent out quick enough, and the device is taking a longer time to process the commands sent. Have you tried just setting one of the to see how long it takes the device to execute. Also if you are sending all of these commands to the power supply to process do you know if it can process more than one command at a time, or if it needs to wait for one command to finish in order to start working onthe next command?  I have never worked with your device before, but GPIB and SCPI are just commands sent over the wire.  It sounds like they are sent in a reasonable amount of time, but each device will be different in their ability to process those commands.  It may be that this is a normal speed for that device.  You could look into some of the documentation to see, or you may already know that the device should be able to process those particular commands faster.