03-24-2013 02:45 AM
Hi,
I am planning to control 2 solenoid valves (SMCVT307V) with labview using solid state relays, and I just want to confirm that the SSRs I have chosen are appropriate for NI-6211. I thought of choosing Crydom CN240A05 which works with a voltage of (3-12 V) and the load voltage is 240 VAC with 2 A. Each DAQ digital outputs provide 16mA which I though is proper for the SSR with a typical input current of 15mA at 5VDC.
I am new to labview system and any help will be appreciated,
Thansk,
04-25-2013 10:23 AM
Hi Armina100,
I am no expert, but I think you might have a hard time driving those relays with your DAQ. I think the relays you picked requiered about 100mA to "close" the contact. My experience with this USB DAQs is that you can not load them too much [low single digits mA].
Also since you will be using AC solenoids I would recomend you to use zero-crossing relays to reduce posible noise/jitter/etc.
What I normaly do when using relays is to add and aditional transistor [2n2222a or similar] and a resistor so provide enough power to it. [make sure you use an external source for it, not the internal 5V of the DAQ.
Here is a link to a video tutorial something else, but the idea is the same.
http://www.youtube.com/watch?v=5bHPKU4ybHY
I hope that helps,
04-26-2013 01:41 AM
Thank you so much for your reply Ilbanez. I changed my SSR to a relay that has a DC output to match my solenoid valve (SV has a DC input). I bought an Omron SSR and it is working fine. I do nor have a resistor in the system but great point; I ll add that as well. Thanks