Holding the value from Modbus Master Query: software o hardware problem?

[StefanCZ]

Hi all, 

I'm working on a project with a torque tool that has its own controller, and I have to make a program in Labview to select some stuff, monitor and save data. I'm using the Modbus/TCP protocol, and with the modbus library in Labview so far I've had no problems reading and writing, except for 1 signal:

The torque tool can save up to 99 diferent Channel/Jobs (different torque curves), and I need to be able to select them with Labview. What I expect is that I write the register once at the beggining of the program, and then the channel remains selected until the job is done and the user wants to change it to do another job. But the problem is that when I make the writing in the MB Ethernet Master Query (multiple coils), the signal doesn't stay turned ON as I need it. If I debug it, I see that it just stays ON for miliseconds, and right after the Modbus makes the writing it turns OFF.

If I put the block  in a while loop, it acts as if it was a continuous signal, but the problem is that when the code starts growing up to include all the other stuff, it adds some delay and it no longer acts as a continuous signal (mostly yes, but it has some shutdown peaks for some miliseconds, which visually doesn't affect too much, but it resets the channel/job and that stops the torque tool, which of course is unacceptable for the application).

So my question is: is there anything I can do to solve that programmatically in the labview code? (forcing the " MB Ethernet Master Query (multiple coils)" to stay ON after they are written, or giving high priority to a specific while loop containing only that writing?),  Or do I need to contact the provider of the torque tool and ask them about setting the channel/job selection signal without writing it continuously?

[mikeporter]

I would be talking to the company that makes the controller as there are two likely options:

1. There is a bug in their controller
2. You are not clear on how to use it

Mike...