Installation Guide
Models M90/91™
This guide provides basic information for Unitronics’ M90/91™ OPLC™.
M90/91™ OPLC™ are palm-sized programmable logic controllers that comprise a built-in operating
panel containing a multilingual text-only LCD screen and a keypad. M90 series offer a single text line
display. M91 offers 2 text lines.
All M90/M91 controllers comprise a serial port. M90 series support
RS232 only. An M91 serial port may be set to RS485.
CANbus and SMS/GSM support are model-dependent features.
M90/91 supports digital, high-speed,
and analog I/Os via:
Onboard I/O Configuration
Differs from model to model.
I/O Expansion Modules
Via I/O expansion port, most
M90 models can be
expanded by up to 64 I/Os,
M91 by up to 96. Check the
specifications of your model
for details.
Write both the HMI and Ladder control application using U90 Ladder freeware.
The M90 User Guide and the product’s technical specification sheet contain additional information.
These documents are located on the Unitronics’ Setup CD. They may also be downloaded from the
Technical Library at www.unitronicsplc.com.
Rubber seal (mounted in back of panel)
5-pin CANbus connector and CANbus network termination resistor (CANbus models)