USB-1616HS-4 DIO for SSR

[Sam Darr]

We purchased a USB-1616HS-4 for our system. We planned on using the digital I/O (DIO) ports to drive these solid state relays https://www.sparkfun.com/products/13015 without realizing the DIO ports cannot provide the necessary voltage. We tested it out and the ports only provide about 2.6V but the SSRs require 3V minimum. Is there a solution you recommend that will allow us to use the USB-1616HS-4 to drive SSRs? Maybe there are different SSRs you recommend? Or can we plug your SSR-RACK24 into the USB-1616-HS-4? Note that we also have the AI-EXP48 plugged into the USB-1616HS-4 for thermocouple measurements.

FYI, the SSR output is connected to a 120VAC solenoid valve that has a peak current of 70 mA. We plan on having as many as 15 solenoid valves that we need to actuate with the USB-1616HS-4.

[DAQman]

Hey Sam,

There is no canned solution that we offer. The digital outputs are 3.3 volt compatible and can only source about 1mA. They work well when interfaced to 3.3 volt logic.

You could try using the output as a switch to ground. Connect the SSR (+) control line to (+) Power (external power supply) and the (-) to the USB-1616HS-4 output. Connect (-) Power to the USB-1616HS-4 ground. When the output is set high, the SSR will be off but when it is set low current will flow from (+) Power down through the output to ground, which is (-) Power and this turns on the SSR. Test the output with a load on the SSR output because they need some current to flow to stay on.

Best regards,

John

[Sam Darr]

Thanks John