Purpose and Description of the Module
The SfAR-1M-4DI-M module is an innovative device that provides a simple and cost-effective extension of the number of lines of input in popular PLCs.
The module has 4 digital inputs with configurable timer/counter option, which allows to connect two encoders. All inputs are isolated from the logic with optocouplers. Each channel can be individually configured in one of several modes.
The module has a fast non-volatile FRAM memory that stores values of the counters and the counters captured. This means that even after a power failure, these values are stored and can further be used, when the power returns
The module is connected to the RS485 bus with a twisted-pair wire. Communication is via Modbus RTU or Modbus ASCII. The use of 32-bit ARM core processor provides fast processing and quick communication. The baud rate is configurable from 2400 to 115200.
The module is designed for mounting on a DIN rail in accordance with DIN EN 5002.
The module is equipped with a set of LEDs to indicate the status of inputs and outputs, which is useful for diagnostic purposes and helping to find errors.
Module configuration is done via USB by using a dedicated computer program. It also allows for changing the parameters using the Modbus protocol.
10-38 V DC; 10-28 V AC
Power consumption (with active Modbus transmission and high state on all inputs)
1 W at 24 V DC
2 VA at 24 V AC
No. of inputs
Low state "0"
High state "1"
PNP or NPN
1 kHz (max.)
500 μs (min.)
-20°C to +65°C
-40°C to +85°C
2 x 3 pin
Up to 128 devices
The appearance and dimensions of the module are shown below. The module is mounted directly to the rail in the DIN industry standard.