Dual Relay Board
ntmntm45036
Posts: 3
in Accessories
First, the board works as advertised. Thanks.
What I do not understand is:
When powered on, voltage at the Commons and Normall Closed lines are 124 volts, as measured on a DMM. But I also see just under 3 volts on the Normally Open lines. This doesn't make any sense. Any help or comments would be appreciated.
What I do not understand is:
When powered on, voltage at the Commons and Normall Closed lines are 124 volts, as measured on a DMM. But I also see just under 3 volts on the Normally Open lines. This doesn't make any sense. Any help or comments would be appreciated.
Comments
Is it a Parallax product?
Do you have a schematic?
What is the microcontroller your using?
What is your application?
People need to know the particular's.
No, I do not have a schematic, but Parallax does and it can be found on their site where they talk about the product.
The microcontroller doesn't matter, as the board is all by itself in this case.
The application might matter eventually, but as I said, the board is all by itself.
If the board is given the 12 VDC is expects, it functions. It does nothing, but it functions. You can test for power at Commons, Normally Open and Normally Closed. I expected AC line voltage at Commons and at Normally Closed, and that is what I saw. I expected to see zero volts AC at Normally Open, but instead got a measurement of just under 3 volts AC using a DMM. I am measuring between neutral and hot.
The board is controlled by 2 signals on J4 pins 3 and 4. Pin 3 controls K1, Pin 4 K2. The circuit controlling the relays must also share a ground connection with the relay board.
That is normal operation so far. The 3VAC is line noise being picked up by the meter due to it's high impedance input. If you now put 3.3V or 5V signal on pin 3 or 4 the appropriate relay should be activated and you should measure AC line voltage on the NO and 3V or so on the NC.
What type of load are you switching? Don't go over contact rating for the relay, or the contacts could fuse together. Had that happen once switching DC.
As I said, the board functions as expected, and no, the load will be far under what it can handle. I have already used the board in a protoype and think good things about it.