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I have 9 identical GPIB devices. Can i send same command to all of them at once?

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I have 9 identical GPIB devices. Can I send same command to all of them at once? Instead of sequentially to each one at a time.

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Accepted by topic author Netsballer92

This is possible with board level GPIB control. While communicating on device level the actual adressing protocol on the bus who is going to talk and who is supposed to listen is handled automatically by the controller (your GPIB interface in the computer), on board level you have to do all this addressing yourself.

When using VISA you use device level addressing by specyfing the VISA resource name "GPIB<controller>::<device>::INSTR". For board level addressing you use "GPIB<controller>::INTFC" instead. When doing that you can't just use a VISA Write and hope everything works since no device has been configured as talker and listener yet. You have to do the talker and listener setup yourself by using the VISA GPIB Command function.

 

You then have to construct the command string to send with this function according to the description here.

So lets assume you have a standard setup where your controller has the address 0 (the default) and you have three devices with primary address 4, 5, 6 and you want to send them a command.

You would therefore send a string with the VISA GPIB Command function that consists of "?@$%&" which is 

 

? Unlisten to tell all devices to stop listening

@ to tell that device 0 (the GPIB controller) is going to talk

$ that device 4 should listen

% that device 5 should listen

& that device 6 should listen

 

After that you can use the normal VISA Write on the board level VISA resource to send a message to device 4, 5, and 6 at the same time. Then issue another VISA GPIB Command with the string "?" to deaddress all the devices to make sure they won't be spuriously interpreting other messages that might follow.

 

 

Rolf Kalbermatter
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