How to connect an Intermec printer to a PLC

One thing I can say with confidence about Intermec printers is that they are the most versatile on the market. Intermec printers can run user developed programs and they have a wide variety of add on options.

I recently did a job for a medical manufacturer who wanted to control label printing from a Programmable Logic Controller (PLC).  They use Bartender to send the label data and needed the printer to print one label each time the PLC fires a relay.

Intermec offers an industrial I/O board for their PX and PM series of printers (1-971143-800 and 270-192-001, respectively) that have 8 sense inputs, 8 optocoupler out ports, and 4 relay ports. The manual is here.

I used a Fingerprint program and an I/O board to connect their PX6 printers to a PLC.

When the program starts it turns on a relay that is used as a “ready” signal to the PLC indicating that it’s ready for a new job.

A fingerprint program then receives label data from Bartender on the Centronics port, filters out unneeded data and writes the label to disk.  The program then turns the  “ready” relay off, indicating that to the PLC that a job is running.

If an error occurs (out of labels, ribbons, etc.) another relay is closed to flag the PLC of the error condition and the specific error is displayed by the printer for the user’s intervention.

The program monitors one of the sense input ports and prints one label when it detects voltage on that pair (10V to 40V). The setup during testing looked like this:

The industrial I/O board uses a 44 pin high density connector for the inputs and relay pairs. We used the red pair of wires and a 24 volt power supply to simulate the PLC output, the black pair was “ready”,  and the white pair was the error indicator. I used a serial port to connect to Bartender because I didn’t have a Centronics port available. We could have used any port, Ethernet, USB, serial, or parallel to receive the label data from Bartender.