GPIB card slave mode

[dlbair55]

Hi,

I have 2 test systems (PC's with their own GPIB cards) that need to get GPIB information from the same device (thermal chamber #30). I know that there can be only one system controller on the bus, so my thought was to have one test system GPIB card be the master (system controller) and the other test system GPIB card be a 'slave' listener and appear to be another GPIB device with its own address(#7). That way I could read the thermal chamber data with the master system and then pass or write that data to device address #7 (the slave test sytem GPIB). The problem is that when I do a 'scan for instruments' from the master system, it does not recognize the slave device, so when I send data to device #7 , I get a LabVIEW error. Does anyone know how to make this work? A screen shot from both GPIB device properties is attached. Thanks..

[Peter Leung]

QUOTE (dlbair55 @ Jan 27 2009, 11:35 AM)

Hi,

I have 2 test systems (PC's with their own GPIB cards) that need to get GPIB information from the same device (thermal chamber #30). I know that there can be only one system controller on the bus, so my thought was to have one test system GPIB card be the master (system controller) and the other test system GPIB card be a 'slave' listener and appear to be another GPIB device with its own address(#7). That way I could read the thermal chamber data with the master system and then pass or write that data to device address #7 (the slave test sytem GPIB). The problem is that when I do a 'scan for instruments' from the master system, it does not recognize the slave device, so when I send data to device #7 , I get a LabVIEW error. Does anyone know how to make this work? A screen shot from both GPIB device properties is attached. Thanks..

When you do a 'scan for instruments' from the master system, the 'slave' does not reply is normal.

The GPIB card does not have any function for reply. Running MAX on the 'slave' won't work, because the MAX does not run any background VI to Read (similar to Listen in TCP/IP).

You need to write your own VI with VISA Read without timeout and VISA Write back something. Very much same as working with COM port. For start, write a GPIB echo VI to echo everything from read to write, and run the VI on the slave to test the connection. FYI, the VISA resource used for the VI will be the 'master'.