M91-2-UN2 Unitronics M91 Textual display and keyboard HMI and PLC onboard I/Os expands up to 150 I/Os

Why Choose the Unitronics M91-2-UN2 Micro PLC with Integrated Text HMI?

The Unitronics M91-2-UN2 is a compact micro PLC with integrated text-based HMI from the Unitronics M90/M91 series. It combines programmable logic control, operator interface and onboard I/O within a single controller, reducing panel space, wiring complexity and overall system cost for small and medium industrial automation systems.

The controller includes a built-in two-line LCD display capable of showing 16 characters per line together with a 15-key keypad. This allows operators to view system information, navigate menus and modify parameters directly from the controller without requiring an external HMI device.

The M91-2-UN2 offers flexible onboard I/O with 10 digital inputs, 2 universal analogue / temperature inputs and 12 transistor outputs. Two inputs can function as high-speed counters or shaft-encoder inputs, and the first two outputs can operate as PWM high-speed outputs, enabling advanced control of sensors, actuators and automation equipment.

Key Features

• Integrated PLC and text HMI in a single compact controller.
• 2-line LCD display with 16 characters per line.
• 10 digital inputs for sensors and automation signals.
• 2 universal inputs supporting analogue, thermocouple or PT100 signals.
• 12 transistor outputs for controlling industrial devices.
• 2 high-speed counter inputs for encoder or frequency measurement.
• 2 PWM capable high-speed outputs.
• RS232 and RS485 serial communication.
• I/O expansion support for additional modules.

Technical Specifications

• Manufacturer: Unitronics
• Series: M90 / M91
• Model: M91-2-UN2
• Controller type: Micro PLC with integrated text HMI
• Display: STN LCD monochrome display
• Display size: 2 lines × 16 characters
• Keypad: 15 operator keys
• Supply voltage: 12 / 24 V DC
• Digital inputs: 10 inputs
• Universal inputs: 2 inputs (0–10 V, 0–20 mA, 4–20 mA, PT100 or thermocouple)
• High-speed inputs: 2 counter / encoder capable inputs
• Digital outputs: 12 transistor outputs (PNP)
• High-speed outputs: 2 PWM capable outputs
• Communication ports: RS232 / RS485
• Program capacity: approx. 36 kB ladder logic
• Expansion capability: supports local I/O expansion modules
• Protection rating: IP65 / NEMA 4X when panel mounted
• Operating temperature: 0 °C to 50 °C

Typical Applications

• Machine automation and OEM equipment.
• Water treatment and pump control systems.
• Packaging and material handling machinery.
• Industrial process monitoring and analogue control.
• Standalone automation systems requiring a simple operator interface.

Trusted by Automation Engineers

Unitronics M90 and M91 PLCs are widely used because they combine PLC logic control and an integrated operator interface in a compact and cost-effective platform for industrial automation.