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M91-2-RA22 Unitronics M91 Textual display and keyboard HMI and PLC onboard I/Os expands up to 150 I/Os
Unitronics M91-2-RA22 Micro PLC with integrated text HMI, featuring 12 digital inputs, 2 analogue inputs, 2 temperature inputs, 8 relay outputs, 2 analogue outputs and RS232/RS485 communications.
£734.85
Why Choose the Unitronics M91-2-RA22 Micro PLC with Integrated HMI?
The Unitronics M91-2-RA22 is a powerful Micro PLC with integrated text-based HMI, designed for industrial automation applications that require machine control, temperature monitoring, analogue processing and operator interaction within a single compact platform. As part of the trusted Unitronics M91 series, it combines PLC functionality, an integrated operator interface and onboard I/O to reduce hardware costs, minimise panel space and simplify installation.
Featuring a built-in 2-line, 16-character LCD display and a durable 15-key keypad, the M91-2-RA22 enables operators to monitor process values, adjust parameters and perform diagnostics directly from the controller. This eliminates the need for a separate HMI while maintaining a simple and reliable user experience.
With 12 digital inputs, 2 analogue inputs, 2 temperature measurement inputs, 8 relay outputs and 2 analogue outputs, the M91-2-RA22 is ideally suited to process control, HVAC systems, water treatment, OEM machinery and industrial automation projects. Integrated communications and I/O expansion capability provide flexibility for future system growth.
Key Advantages
- Integrated PLC and operator interface in one compact controller.
- 2-line LCD display with built-in keypad.
- 12 digital inputs including high-speed counter functionality.
- 2 analogue inputs and 2 temperature measurement inputs.
- 8 relay outputs and 2 analogue outputs.
- Supports thermocouple and PT100 temperature sensors.
- Built-in RS232 and RS485 communications.
- Expandable up to 150 I/O points.
Key Features
- Unitronics M91 Micro-OPLC platform.
- 2-line × 16-character LCD display.
- 15-key membrane keypad.
- 12 digital inputs.
- 2 analogue inputs (0-10V, 0-20mA, 4-20mA).
- 2 temperature measurement inputs supporting PT100 and thermocouples.
- 8 relay outputs.
- 2 analogue outputs (0-10V, 4-20mA).
- 1 high-speed counter / shaft encoder input.
- RS232 and RS485 serial communications.
- Auto-tune PID control with up to 4 loops.
- Real-time clock with battery backup.
- I/O expansion capability up to 150 points.
Ideal for Temperature and Process Control
The Unitronics M91-2-RA22 is specifically designed for applications that require both process measurement and machine control. The integrated analogue and temperature measurement inputs allow direct connection of transmitters, PT100 sensors and thermocouples without requiring additional expansion hardware in many applications.
Combined with analogue outputs, PID functionality and relay outputs, the controller can efficiently manage heating, cooling, pressure control and other process automation tasks. Its integrated display and keypad provide operators with immediate access to system information and control functions.
Typical Applications
- HVAC and environmental control systems.
- Water and wastewater treatment plants.
- Industrial process control.
- Boiler and temperature control systems.
- Pump and pressure management applications.
- OEM machinery and equipment.
- Food and beverage processing systems.
- Building management systems.
Technical Specifications
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| Supported Protocols | Modbus RTU | |
|---|---|---|
| Product Series | Unitronics M91 | |
| Touch Technology | Keypad (non-touch) | |
| Communication | RS232, RS485 | |
| Device Type | HMI + PLC | |
| IP Rating | IP65 | |
| Series | M91 | |
| Product type | Micro PLC with integrated HMI | |
| Power supply | 24 V DC | |
| Digital inputs | 12 | |
| Analogue inputs | 2 | |
| Temperature inputs | 2 (PT100 / Thermocouple) | |
| Relay outputs | 8 | |
| Analogue outputs | 2 | |
| High-speed counter | 1 × 10 kHz, 32-bit | |
| Display | STN LCD, 2 lines × 16 characters | |
| Keypad | 15 keys | |
| Communication ports | RS232 / RS485 | |
| Protocol support | MODBUS | |
| Program memory | 36 KB virtual ladder memory | |
| Expansion capability | Up to 150 I/O points | |
| Protection rating | IP65 / NEMA 4X when panel mounted | |
| Operating temperature | 0°C to 50°C | |
| Mounting type | Panel or DIN rail mounting |
Frequently Asked Questions
What is the Unitronics M91-2-RA22 used for?
The M91-2-RA22 is used for industrial automation applications requiring machine control, temperature monitoring, analogue processing and integrated operator interaction.
Does the controller support temperature sensors?
Yes. The controller includes 2 temperature measurement inputs supporting PT100 RTDs and thermocouple sensors.
How many outputs are available?
The M91-2-RA22 provides 8 relay outputs and 2 analogue outputs for process and machine control applications.
Can the controller be expanded?
Yes. The M91-2-RA22 supports expansion modules and can be expanded up to approximately 150 I/O points depending on system requirements.
What communication options are included?
The controller includes RS232 and RS485 communications with MODBUS protocol support for integration into industrial automation systems.
Trusted by Industrial Automation Professionals
Unitronics M91 Micro-OPLC controllers are widely used in industrial automation, process control and OEM machinery applications, providing dependable PLC functionality, integrated operator control and flexible process monitoring capabilities within a compact platform.
