The ACS Control-System MIR-491 and MIR-492 are compact universal process controllers in 1/16 DIN (48 × 48 mm) panel-mount format. They handle ON/OFF, PID (2-point, 3-point, and continuous), motor step actuation with position feedback, and cascade control — covering temperature, pressure, flow, and level loops from a single instrument platform. The two models share the same core functionality; the MIR-492 adds the option slots for the second universal input (INP2), third input (INP3), digital outputs (OUT5/OUT6), and fieldbus communication.

What sensor types can the MIR-491/492 accept directly?

The primary universal input (INP1) accepts thermocouple types L, J, K, S, R, T, C, D, E, and B; Pt100 RTD in 2- or 3-wire connection (-200 to +850 °C); and linear signals 0/4–20 mA and 0/2–10 V. KTY 11-6 linearization is preset, and custom sensor curves can be loaded via the BlueControl engineering software. The optional INP2 analog input can be configured for heating current measurement, external set-point, position feedback (for motor step control), or a second process value for differential or ratio control.

What output configurations are available?

Every unit includes two relay outputs (OUT1, OUT2) as potential-free changeover contacts rated 250 V AC / 2 A — typically assigned to heating and cooling. OUT3 and OUT4 are configurable as either additional relays or universal outputs delivering 0/4–20 mA, 0/2–10 V, transmitter supply (22 mA), or logic-level for solid-state relay drive. The MIR-492 can add two galvanically isolated digital outputs (OUT5, OUT6) via opto-coupler, rated 18–32 V DC.

How is the controller configured and monitored?

Configuration and parameter backup are handled through the BluePort front-panel interface using the free BlueControl engineering software. The controller displays process value and set-point simultaneously on a dual-line LCD with bargraph and plain-text status messages. Two complete parameter sets can be stored and switched at runtime — useful for products that run two distinct recipes. Built-in diagnostics include a maintenance manager, operation hours counter, switching cycles counter, heating current alarm with SSR short-circuit detection, and a configurable error list with sensor-break behaviour options.