fx2n/gx Developer

i just want to know if is possible to run the PLC program without conecting fysical I/O, and then monitor the output/input led while the PLC is conected to a PLC using GX-developer.can the input condition be set using force on funktion while the program is running. i did this but when i use the force function but while the PLC was in run mode i did,nt notice any thing on the led. when i use the force function while the PLC was in stop mode, i could get the output let lit , but not the input led.

Generally, LEDs on input modules indicate the presence of current flow at the module's terminal. The LED is telling you that you have a complete circuit between the field device and the PLC.

The LEDs on output modules usually indicate that the PLC is commanding the output to be true, but not necessarily that there is current flow to the field device.

There are exceptions to these generalities, and I can't tell you for sure whether Mitsubishi is one of the exceptions.

Jerry,
You can use shift + enter key to turn on your inputs, internal relays, etc. in your program, but as Steve has mentioned, you will not see the LED come on, as this is an indication of current flow. To force on an output, you can turn on all the conditions before that output, or if you want to use the force function then that output cannot be in the progam. IOW, you'll have to delete it to force it on. I would just turn on the conditions on the same step to get the output to come on.
Tim