An affordable All-in-One controller: a smart PLC with a textual HMI and keyboard, plus onboard I/O configurations; expands up to 150 I/Os.


  • Shaft-encoder inputs and PWM outputs
  • Direct temperature inputs
  • Auto-tune PID, up to 4 loops
  • Date & time-based control Database
  • Full source upload




  • Up to 80 user-designed screens
  • Multilingual: supports over 15 languages and 20 graphic symbols
  • Scroll between pre-programmed recipes/menus
  • Memory and communication monitoring  via HMI – No PC needed


  • SMS messaging via GSM
  • Remote access utilities
  • PC access via MODBUS or OPC server
  • Supports MODBUS protocol
  • CANbus  (in C models only)
  • User-defined ASCII strings, enable communication with external devices
  • RS232/RS485 built-in port




I/O options include digital, analog, high-speed, temperature & weight measurement. See table below:

  • M91™ models – Onboard I/Os
  • I/O Expansion Modules


I/O Expansion
I/Os may be added via expansion port. Expand up to 150 I/Os
Application Memory 36K (virtual) Ladder code capacity
Memory Operands 256 coils, 256 registers, 64 timers
Database 1024 integers, (indirect access)
Type & colors STN LCD
Display 2 lines x 16 characters
Keys 15 keys
Power Supply M91-2-R1 / R2C / T1 / T2C / UN2 : 12/24VDC
M91-2- R6C / R34 / T38 / UA2 / RA22 : 24VDC
Battery 7 years typical at 25°C, battery back-up for all memory sections and RTC
Clock Real-time clock functions (date and time)
Environment IP65/NEMA4X (when panel mounted)
Standard CE, UL  Many of our products are also  UL Class 1 Div 2 and  GOST certified  –  please contact Unitronics