EM231 Analog Input (231-0HC32)

4AI×12BIT,Current/voltage input.Isolation.

Order No.:CTS7 231-0HC32

Specification:4AI×12BIT, Current/voltage input.Isolation.

Product Description

Order Data

Order Data

Order No.

CTSC-200 EM231 Analog Input Module, 4AI×12BIT, Voltage/Current Input, Isolation      CTS7 231-0HC32


Technical Spec

Performance Parameters


EM231, 4 AI×12BIT

Physical Features



   Power Loss(dissipation)


Power Consumption

    From +5V(from I/O bus)

34 mA

    From L+

40 mA

    L+  voltage range,class 2 or DC sensor supply

20.4~28.8V DC

    LED indicator

24 VDC Power Supply  Good
           ON = no fault,
           OFF = no 24 VDC power

Analog Input Feature 

    Number of analog input points

4 points

    Isolation(field side to logic circuit)

Optical isolated: 500VAC, 1 minute

    input type


    Input Range


0~10V, 0~5V


±5V, ±2.5V


0~20 mA

        Data Range


        Bipolar,full-scale range


        Unipolar, full-scale range


Input Resolution


2.5 mV (0~10V)

1.25 mV (0~5V)


2.5 mV (±5V)

1.25 mV (±2.5V)


5μA (0~20mA)

    Analog to digital conversion time


    Analog input step response


    Common mode rejection

40dB,DC to 60Hz

    Common mode voltage

Signal voltage + Common mode voltage < 12V

    Input Impedance


    Input filter attenuation

-3db @ 3.1kHz

    Maximum input voltage


    Maximum input current


    ADC resolution



Calibration and Configuration
  • Location of the calibration and configuration switch

  • Input Calibration

The calibration adjustment will affect the instrumentation amplifier stage which follows the analog multiplexer. so the calibration affects all user input channels. Variations exist in the component parameters of each input circuit before the analog multiplexer will cause slight differences in the reading values between different channels connected to the same input signal even after calibration.

If need to acquire the specifications contained in this data sheet, may be you need to enable analog input filters for all inputs of the module. Please select 64 or more samples to calculate the average value.

To calibrate the input, please use the following steps.

    1. Turn off the power to the module, select the desired input range.

    2. Turn on the power to the CPU and module. Allow the module to stabilize for at least 15 minutes.

    3. Using a transmitter, a voltage source, or a current source, connect a full-scale value signal to one of the input channels, read the value reported to the CPU.

    4. Adjust the GAIN potentiometer until the reading is 32000.

  • Configuration

Table 1 shows how to configure the EM 231 module using the configuration DIP switches. Switches 1, 2, and 3 select the analog input range. All inputs are set to the same analog input range. In this table, ON is closed, and OFF is open. (SW4 toSW6 should be set to the OFF position)

Table 1   EM 231 Configuration Switch Table to select Analog Input Range


Full-S cale InputResolution


OFFON0 to 10V2.5mV
ONOFF0 to 5V1.25mV
0 to 20mA5 uA
BipolarFull-Scale InputResolution
ONOFF± 2.5 V1.25mV

Input Data Word Format


The 12 bits readings of the analog-to-digital converter (ADC) are left-justified in the input data word format. The MSB is the sign bit: zero indicates a positive data word value. In unipolar format, the three trailing zeros cause the data word to be changed by a count of eight for each one-count change in the ADC value. In bipolar format, the four trailing zeros cause the data word to be changed by a count of sixteen for each one count change in the ADC value.


Size  Diagram

Wiring Diagram 


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