I’m looking to remotely trigger contact closure on a commercial mass spectrometer. Typically these instruments are triggered by another instrument - but all it’s really doing is grounding out a pin normally at 5 Vdc. I’ve planned to use two Arduino chips to transmit/receive wirelessly, with the receiver then triggering a 10V 5A all-purpose relay to bring the HI pin common with ground. I know that my wireless communication works because I can make the relay click; I know that grounding the pin manually works because I can trigger the instrument that way. But I can’t trigger contact closure.
The NCD devices advertise a nice range, but the relay looks similar to what I have. How can I know if an NCD device pair will work for my application? (I’m also doing other functions, so I would want to trigger the NCD pair itself with TTL logic.)
Hi,
Our relays don’t provide any power to the contact so they can be used to switch power if power is connected to them or dry contact if no power is connected to them.
If you connect one side of the contact closure input you have to the Common of our relays and the other side of the contact closure to Normally Open of our relays then it will output a contact closure.
Sounds promising! I need < 20 ft. of range of communication; what device model do you recommend for small, cheap, and triggerable by TTL?
Unfortunately we don’t have anything designed to be controlled directly through TTL. If you have a setup that activates the a relay already then most likely its a wiring issue on the relay contacts if its not working. You can use a multimeter to check for continuity and see if its just a faulty relay.
That’s what I would have thought, but when I trigger my relay I can see that continuity between the NO pins is established. The issue seems to be that while I can trigger the contact closure by dry connection, the instrument I want to trigger is itself providing the pin voltage I wish to ground out.
But if the your devices can’t be triggered with an external HI pin it’s moot.