Setting default states NI 9401

[Tbur]

Hello,

I'm using the cDAQ 9188 with a NI-9401 digital I/O module along with some other modules to control a machine from a remote location, and the machine needs to turn off if network communication is los. Is it possible to set to a default state of the NI-9401 if the network connection is lost, or do the modules stay at the last set state.

Tyson

[Joe_S]

Hello Tyson,

Thank you for posting.  Let me make sure I understand what the situation is.  You have some network machine that you are controlling with your computer, and when you lose communication with that machine, you want to turn off your NI-9401.  A little more information about your setup would help us get on the same page.  

What program are you using to control your cDAQ modules (LabVIEW, CVI, etc)?

How are you controlling the remote machine and are you expecting to lose communication with it?  How will you know when you have lost communication?

To what is the 9401 connected? Can you provide a connection diagram that shows what devices are connected to what?

Thanks.

Regards,

Joe S.

[Tbur]

Hello Joe,

I'm using a LabView program and several cDAQ modules to remotely push buttons and monitor operation of a machine over a network connection. One of the digital outputs on a NI-9401 will be connected to a system Start/Stop relay. I would like to have the relay turn off if communication is lost between the computer running the application and the cDAQ chassis.

Thank you,

Tyson

[Joe_S]

Tyson,

Let me make sure I understand the issue.  You are using a cDAQ chassis to monitor the operation of a machine, and one of the modules in the chassis (the 9401) is controlling a power relay.  If communication between the computer and the cDAQ chassis is lost, you want the 9401 module to turn off the relay.  Is this correct?

1.  First, what program are you using to write you code?

2.  I can tell you that the 9401's default power-up state is as an input and the device does not support programmable power-up states.

3.  A chassis receives instructions from the computer that is controlling it.  Once it loses that communication, the device outputs stay in the state that they were in before it lost connection.  Therefore, if an output is high, it stays high.  The module can't receive any more instructions until communication is restored.

4.  How are you using the 9401 to control the relay?  What kind of signals are you generating and how are you implementing this?

5.  Finally, I believe a bigger concern is why you might be losing communication with the device.  Is there a reason why you might be losing communication with it?

There are a number of ways to proceed with a solution for this.  I just need more specific information about what you are doing and what you want to happen.

Regards,

Joe S.