Default DAQmx Output Setting

[droxby]

Hello Everyone,

I am currently using a USB-6341 and a USB-6221 to control two different actuator and valve combinations which are part of a coolant flow control system. Basically, the DAQ device reads a temperature sensor, and with a PID algorithm outputs a voltage to proportionally open the actuator-valve.

Being in the development phase, we occasionally have a few problems like loosing communication to a DAQ device from the PC it is connected to.

Is there a way to set the default value of the DAQ so that in the event of a communication loss, it would output the maximum value of 10 volts? 10 volts corresponds to maximum coolant flow, which is much safer than none with that we're developing.

Thanks,

Daniel Roxby

CASS

[JVP]

Hi Daniel

For your application you will need an external circuit. You can use the USB-6341, because it has a watchdog timer. Basically, you pragmatically update the watchdog timer. When the device is disconnected the watchdog timer is not updated, and will eventually expire. The watchdog timer then can set a high on a PFI or Digital line. You can then set off a relay switch and switch from AO to 10V. There is a watchdog example you can find here. 

Best Regards,

Jignesh