VIPColor VP6 Series, User Manual

Page: 79 / 84

Appendix
79
Printer Interface (GPIO) Specifications
The Printer Electrical Signal Interface and Protocol is developed to coordinate the
printing of labels with an external process in a production workflow. Using this
protocol, the printer (Device A) receives a print job but will not print until it receives
a signal from an external device (Device B).
The following scenario illustrates how this could be used:
1. A box on a conveyor arrives at a workstation. A barcode is read and triggers a
message to a computer.
2. The computer sends a print job (probably with some variable data) to the printer.
3. The box reaches the next station on the conveyor and triggers a signal (e.g. by a
footswitch or automatically by a sensor). The printer starts printing when the
signal is received.
The electrical signal to initiate printing is received at the printer’s GPIO port. The
handshaking protocol is as follows:
• The printer signals it is ready to print by pulling up the Print Job Ready signal
from low to high.
• Device B signals it is ready by pulling up the Ready signal. This must remain high
for at least 50 ms. When the Ready signal is pulled down while the printer is
printing, the printer will pause and behave exactly the same way as if the user
presses the Pause button on the control panel. The printer remains in Pause
mode until the Ready signal is pulled up again for at least 50ms.
• The printer prints and pulls down the signal when printing is completed.
• No printing occurs whenever the Printer Error signal is pulled low.