Problem is, every relay briefly engages on reset, then normal function.
I am using the Raptor, with load modules to control a Triac Relay, which in turns controls a motor starter.
I initially started out with a FEZ Cerberus, doing the same task, using a straight breakout board to control the Triac’s, but because the control wire would go thru a power cabinet, things like an Air Compressor starting would cause enough voltage to trip the Triac, and bump the fans briefly.
The solution to this was to switch to the load module, and switch the Ground. This removes the possibility of the induced voltage on the control line, and has worked great with the Cerberus ever since.
That said, as the controls keep getting more sophisticated, adding LCD touch screen, Memory, OneWire Ports, Webserver, ect, have moved to the Raptor. Once the Raptor is started, they work great, but on startup at least 4 of the pins briefly go hi, (as shown by the LED lighting on the load module). This ranges from a fraction of a second to about 1 second, but I simply can’t bump that many fans at once. Easy enough, skip the pins, that are causing the problem, although it would be nice to be able to use them.
So here’s the problem, Even without Lighting the LED’s on the load module, I believe the pins are in a “don’t care” state, and enough voltage is on the line, to allow enough voltage to get thru and trip ALL the relays. This only lasts for about a second, (basically till you here the computer chime that a usb device has been found), and then everything works as normal, same as it did with the Cerberus. But I can’t have that happen. I’m using a 12V power supply to drive the Triac’s, and they take nothing for current.
So the question, Can I set the default state of the pins, (probably at the Micro Level), for a default state of pull down resistor?
Second question, Pretty sure a 10k pull down resistor on all the pins would solve the problem, but that involves spinning a board to put in between all the load modules. Any thoughts on that wouldn’t hurt.
Third question, Any thoughts on a 10k pull up resistor, just air wire it between the terminals on each of the relays to solve the problem?
Ideally I’d like to do both set the default pin state, with the pull up resistor, to increase fail safe.