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 HMI?

The Unitronics M91-2-UN2 is a highly versatile Micro PLC with integrated text-based HMI, designed for industrial automation applications that require digital control, analogue signal processing, temperature monitoring and high-speed transistor outputs within a single compact platform. As part of the trusted Unitronics M91 series, it combines programmable logic control, operator interface functionality and onboard I/O, helping reduce installation complexity, save panel space and lower system costs.

Featuring a built-in 2-line, 16-character LCD display and a robust 15-key keypad, the M91-2-UN2 enables operators to monitor process values, adjust machine parameters and access diagnostics directly from the controller. This integrated design eliminates the need for a separate HMI whilst simplifying operation and maintenance.

With 10 digital inputs, 2 configurable analogue/temperature inputs, 12 transistor outputs and advanced communications capability, the M91-2-UN2 is ideal for machine builders, OEMs, process automation engineers and industrial control applications requiring fast response times and flexible analogue monitoring. The controller also supports PT100 and thermocouple temperature measurement alongside analogue signal processing.

Key Advantages

• Integrated PLC and operator interface in one compact device.
• 2-line LCD display with built-in keypad.
• 10 digital inputs and 2 configurable analogue/temperature inputs.
• 12 transistor outputs including high-speed PWM capability.
• Supports PT100 and thermocouple temperature measurement.
• Built-in RS232 and RS485 communications.
• Supports MODBUS networking and industrial integration.
• Expandable up to 150 I/O points.
• Suitable for machine automation and process control applications.

Key Features

• Unitronics M91 Micro-OPLC platform.
• 2-line × 16-character STN LCD display.
• 15-key membrane keypad.
• 10 digital inputs.
• 2 configurable analogue / PT100 / thermocouple inputs.
• 12 PNP transistor outputs.
• 2 high-speed counter inputs up to 10 kHz.
• 2 PWM / high-speed outputs.
• RS232 and RS485 serial communications.
• Auto-tune PID control functionality.
• Real-time clock with battery backup.
• MODBUS RTU protocol support.
• I/O expansion support up to 150 points.

Flexible Control with Temperature Monitoring

The Unitronics M91-2-UN2 combines digital control, analogue measurement and temperature monitoring within a single controller. The configurable inputs can be used as standard analogue inputs or connected directly to PT100 and thermocouple sensors, allowing accurate process measurement without requiring additional signal conditioning hardware.

Its transistor outputs support high-speed switching and PWM functionality, making the controller suitable for machine automation, process control and motion-related applications. Combined with integrated communications and operator interaction, the M91-2-UN2 provides a complete all-in-one automation platform.

Typical Applications

• Temperature control systems.
• Water and wastewater treatment plants.
• Industrial process automation.
• Packaging and labelling machinery.
• OEM machine building projects.
• Pump and pressure management systems.
• HVAC and environmental control systems.
• Food and beverage processing equipment.