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 triggering a fanuc s420 with RJ controller from an external source

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September 10, 2013, 07:14:18 PM
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Hello all,

I'm attempting to start a program on my s420 with a signal from an external PLC. I have no manuals, and I'm learning as I go. Does anyone have any experience with this process?

Thanks in advance.

Today at 05:10:03 AM
Reply #1



September 11, 2013, 03:44:28 PM
Reply #1


The robot is equiped with pre-defined I/O that are used to handshake with a PLC.

Those are 8 bits for program number + a strobe bit, and a start bit (all are called PNS)
You have it as input and output.

When this is enable (through à sysvars), the PLC put a number (1-255) on the robot input and flash the strobe signal.
Then, the robot read the 8 bit and echo them on output by flashing a strobe signal to plc.

Usually, the PLC program compare the number sended and received and if equal then activate the Start bit.

Some other setup should be done, since activating the UOP i/o (with sysvars $opwork.$uop_disable = 0).
First, UOP are virtual i/o, they should be link to real i/o (DI and DO).
The first three UOP input (IMSTP, HOLD and FENCE should be ON to use robot.
The UOP input Enable should also be ON to use the PNS.

By default, the program name called will be PNSxxxx or RSRxxxx (depend on vars setup)

This is a start point for you, hope it helps !
If it starts well the first time, you haven't checked all !

September 18, 2013, 02:28:22 PM
Reply #2


I'm kind of in the same boat. Currently have an OMRON PLC sendong signals via devicenet. Want to migrate to an AB Micrologix 1500 & use digital I/o, just not sure where to land wiring for the I/O. Have no Fanuc manual for this old of a controller.

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