SCM 31x



  • pH and redox/conductivity/DO (SCM 311/312/313) value to 4-20mA-signal conversion
  • Span and offset calibration
  • Temperature compensation
  • Galvanic isolation of inputs and outputs







SCM 311/312/313 is an industrial transducer which outputs 4-20mA current signal proportional to input voltage pH and redox/conductivity/DO signal. Transducer’s inputs are galvanically isolated frоm its output; it may be supplied in wide range of power supply voltages; it has large input impendance; it enables span and offset calibration, and manual and automatic temperature compensation as well. It is housed in watеrproof IP65 plastic case for wall and panel mounting. Device calibration is done using the alfanumeric LCD display with 16 characters in two rows and four buttons keyboard. Galvanic isloation eliminates disturbances caused by ground potential variations, what is very important when it is known that potential of two different grounds in some cases can differ within even a couple of hundreds volts.



SCM 311/312/313 pH and redox/conductivity/DO transmitter is used for accurate and stable pH and redox/conductivity/DO measurements in systems for:

  • Waste water treatment
  • Process automation (e.g. food and chemical industry)
  • Remote monitoring of rivers and lakes pollution


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pH input

(SCM 311)

Galvanic pH probe:

  • combined
  • two-probe system

Resolution 0.01pH

Accuracy 0.02pH

ORP input

(SCM 311)

Standard platinum probe

Resolution 1mV

Accuracy ±2mV

Conductivity input

(SCM 312)

Standard conductivity probe

Resolution 0.01µS

Accuracy 0.02µS 

 DO input

(SCM 313)

Galvanic probe for DO

Resolution 0.1%

Accuracy 0.1%

 Input resistivity

 Higher than 1012 Ω

 Temperature input

 internal sensor,

100Ω RTD,

1000Ω RTD,

manual input

Resolution 1°C

Accuracy ±1°C

 Transmitter voltage

 13V nominal

 Measuring range

 SCM 311: 0.00 to 14.00 pH

                0 to 1500 mV (ORP)

SCM 312: 0.00 to 20.00mS

               0.000 to 2.000mS

               0.0 to 200.0µS

               0.00 to 20.00µS

SCM 313: 0-100% saturation

Temperature range: -20 to 110ºC       


 Measuring cycle


 A/D converter

 SAR 12-bit

Current output

 4-20mA, alarm value 3.5mA/20.5mA

Resolution 0.005mA

Acurracy ± 0.05mA

Working temperature -10°C to 50°C
Hummidity 5 to 95%, without condensing
Display LCD 8 digits 9mm
Power supply From the loop (4-20mA), loop voltage 13 to 32 Vdc
Dimensions 90mm (H) x 115mm (W) x 56mm (D)
Assembly Screw plug, max 2.5mm2
Weight cca 500g