Powering flow meters using M-Series DAQ and SCXI-1180

[ekabo]

Hello everyone,

I have a PXI-6229 M-Series DAQ card controlling an SCXI-1001 chassis with several conditioning modules, including an SCXI-1180 breakout connector. I'm attempting to connect two pulse generating flow meters to the counters on the DAQ card through the SCXI-1180 with an SCXI-1302 breakout accessory. However, the flow meters need 10V power, ground, and the signal line needs pulled up to 5V.

What can I use to produce 10V power in the SCXI-1302 breakout box? Should I use the chassis ground or the digital ground to ground the meter? Can I use the +5V excitation pin, with a resistor, to pull up the signal wires I'm attaching to the counter pins?

Thank you for your help!

Erik

[Joseph-S]

Hi Erik,

[Joseph-S]

Hi Erik,

Do you have a manual for the flow meter? I'm curious to see what the specifications are. You can definitely use the 5V pins with a pullup resistor. However, you need to make sure that you choose the resistor value such that the current draw will not exceed the allowable amount listed in the device spec sheet. The chassis ground is used as a reference for the digital and analog ground according to the SCXI bus manual (http://www.ni.com/pdf/manuals/340298b.pdf, page 6). If you could post the manual or specs of the flowmeter, perhaps I can better assist you in interfacing with the device.

[ekabo]

Unfortunately there isn't a manual; this pump was never meant to be used in isolation of its associated display panel. However, we did manage to get some information about power draw from the supplier, and the instrument pulls too much power to use the excitation from the DAQ. We're going to use an external power supply, and reference it to chassis ground.

Thanks for the reply, and the link to the SCXI bus manual!