Internet PLC Forum

Hi -

I've been using RS-485 to communicate between two PLC's.  Basically, I ran out of Outputs on my FMD-10 PLC and used the RS-485 port to write outputs to my old T100MD.  It's a straight run of about 4' of twisted pair between each 485 port.  In a 1 second scan on the FMD, I have the following code:

WRITEMODBUS 13,1,16, OUTPUT[1]
RELAY[5] = READMODBUS(13,1,0)

My FMD-10 is ID#3, and my slave is ID#1.  There is no comm code running on the slave.  I'm not using a SETBAUD command either.  This has been working fine for months, until I added an additional Output on the slave PLC today.  Once I power cycled the slave PLC, the comms stopped working all together.  I tried using the SETBAUD command to ensure the baud rates were the same on each PLC.  No luck.  

I've also tried changing ID's, reading different registers, etc.  It just seems like the comm port stopped working.

Both PLC's run their intendant programs without issue.  Again, it's been working for months and the only thing I did today was add another output relay on the slave PLC.

I've been reading forums and reference material all day, I'm at a lose.  Any feedback would be appreciated.  





 

Hi,

I plan on using my T100MD PWM output to control a Meanwell Dimmable LED power supply.

The MW PS is looking for a Full PWM Voltage of 10V.  What is common practice here?  Should a supply 10V to the MWPS using a seperate PS or voltage divider?  Or use the 24V and limit the duty cycle to 41%?

Thanks,

Rob