Instrument Control (GPIB, Serial, VISA, IVI)

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About 40 second delay in Modbus communication

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Hello there!

I have a small problem using the following modbus library for LabView8.6:

Modbus Library


After I have started the Slave Demon it takes about 30 - 50 seconds for the first values (send via TCP/IP) to arrive. I have a Graph that plots all the18 read values for me and it always takes a long time to see them jump fom 0 to another value. Afterwards there remains a delay of about 30 seconds regarding how current the shown values are.

I can't post the VI here because it uses a lot of SubVIs which would make it not runable anyway. However, I already checked the Modbus Salve Example VI and there I have the same delay as in my own programm.

Anyone got any ideas?



Thanks in advance and kind regards,


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Accepted by topic author Kambra

Problem solved. It was the device (a data logger) that was acting so slow in sending the data while it was acting as the master. I changed it now to be the slave and read its holding registers. This way the values arrive "immediatelly".

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