I have the fx1n-32mt and I wrote a program for it that mimics a traffic light. I gave the program two modes it can switch between using a button. The indicator LEDs on the unit show that everything works correctly, so I connected some colored leds to the outputs and things started getting a bit wonky. One set of leds imitate a 55 mph zone. They operate just fine. They’re located at Y0, Y1 and Y2. The other set of LEDs were initially located at Y10-Y12. Upon power up, all three were lit, but one was brighter than the rest. The first set continued operating normally. I watched the plc cycle through the program and I saw that it was trying to work normally. If an led was supposed to be on, it was bright. If it was supposed to be off, it was dim.
I considered maybe it was something weird to do with using both sets of outputs. Like maybe Y10-Y17 behaved different than Y0-Y7. So I modified my program and rewired it to use only Y0-Y7, powered it up....and same results. The first LEDs are still normal and the second set are still staying on. I did try out the second mode of the program where it flashes the LEDs. The first set (emulated 55 zone) flashes orange and that works as intended. Second set (emulated 35) flashes red....but all LEDs will actually turn completely off on the “off” part of the cycle. When it reaches the “on” part, all leds come back on with red being the brightest.
I just suddenly realized something. I’m running the plc off of a 16v supply, but I’m using a separate 12v supply for the LEDs. The LEDs (panel-mount assemblies) are rated 12v, which is why. Should I connect the grounds of both supplies together? Usually you would in circuits where two power supplies are used. I’ve been using it like a relay unit because the instruction book doesn’t get too detailed about anything. I’m going to go ahead and post this, but I’m going to go ahead and test my theory...after I rewrite my program to go back to both output addresses. I’ll also draw up a wiring diagram and attach it to this post (unless editing gets locked while I’m away, then it’ll need to be an update post).
*UPDATE*
I took a piece of wire and connected the grounds together and it solved the problem as expected smh.
