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MU-491, MU-492

The MU-491 and MU-492 modules offer four analogue input channels isolated from each other with high insulation strength.

For direct measurement with different temperature sensors, the firmware implements algorithms for linearization of most of the thermocouples including compensation of the "cold end" of the thermocouple (modules are equipped with four temperature sensors located in the immediate proximity of the analog input terminals).

The modules are based on 16-bit A/D converters with system autocalibration running continuously on the background of cyclic measurements. The time needed to measure all channels, including autocalibration and open senzor detection, takes less than 1.2 seconds. Alternatively, floating filters averaging the results of the ten most recent measured values can be activated.

The module also includes two digital inputs with counter capability and two digital outputs.

The analog inputs are isolated from other circuits of module (DIO ports, power supply and RS-485 interface) and from each other with high insulation strength. The digital inputs and outputs are isolated from other circuits and from each other.


Type MU-491 MU-492
Analog inputs 4x U/TC
Analog input topology S.E.
Voltage ranges -10÷+80mV -10÷+30mV
Internal temperature
ADC resolution 16-bit
(continuous offset and range autocalibration)
Basic accuracy better than 0.15% of FSR (U ranges)
better than 1°C of FSR (temperature sensor)
TC linearization E type (-200÷1000°C)
J type (-210÷1200°C)
K type (-200÷1372°C)
N type (-200÷1300°C)
B type (-250÷1820°C)
R type (-50÷1768°C)
S type (-50÷1768°C)
T type (-200÷400°C)
Measurement period less than 1.2s
(the time needed to measure all channels)
Overvoltage protection ±100mA continuously (±200mA max. 1s)
(TVS diodes)
Analog input isolation 4kVRMS (AIN from each other)
(insulation gap & surface path 7.5mm)
(see schematics)
Number of digital inputs 2
Type of digital inputs isolated, bipolar 24V
with 50Hz filter
Digital input signal
(level L)
<3VDC (both polarities)
<3VRMS (signal 50Hz)
Digital input signal
(level H)
10÷35VDC (both polarities)
15÷35VRMS (signal 50Hz)
Overvoltage protection ±60VDC (max. 1s)
60VRMS (signal 50Hz, max. 1s)
Digital input impedance 14kΩ approx.
Digital input isolation 1kVDC (DIN block against other circuits)
100VDC (between DIN channels)
Number of counters 2
Counter frequency 10Hz max.
(signal asymmetry 40/60% max.)
Counter range 0÷4294967295 (i.e. 32-bit counter)
Number of digital outputs 2
Type of digital outputs isolated, 24V
Digital output signal 32VDC/0.3A max.
Digital output isolation 1kVDC (DOUT block against other circuits)
100VDC (between DOUT channels; only MU-415/815)
Supply voltage 10÷30VDC
Power consumption 2.2W max.
Housing & Dimensions Modulbox 6M
Signal terminals screw terminals, wire 2.5mm2 max.