
8 channel analogue signal to digital interface module for converting voltage or current signal inputs to a single RS-485 communication interface using Modbus RTU transmission protocol. The voltage version will accept 0-10Vdc, 2-10Vdc, 0-5Vdc or 1-5Vdc input, and the current version will accept a 0-20mA or 4-20mA input.
Product Parameters
- Power supply voltage: 24V DC typically
- Maximum supply voltage fluctuations: from +16V DC to +30V DC
- Current consumption: 55 mA typically
- Number of independent analogue inputs: 8
- Inputs (depending on version):
- SIAi-8P: current 0-20 mA; 4-20 mA
- SIAi-8N: voltage 0-10 V; 2-10 V; 0-5 V; 1-5 V
- Measurement accuracy: ± 0.25% ± one digit
- Accepted prolonged inputs overload: 20%
- Galvanic separation: all 8 inputs are galvanically isolated from module supply and RS-485 interface
- Communication interface: RS-485
- Transmission protocol: Modbus RTU
- Baud rate: 1200 ÷ 115200 bit/sec.
- Number of modules in a single network: max. 128
- Data memory: non-volatile memory, EEPROM type
- Operating temperature: 0°C ÷ +50°C
- Storage temperature: -10°C ÷ +70°C (standard),
- Humidity: max. 90%, non-condensing
- Protection class: IP 20 (housing and connection clips)
- Installation method: on the 35 mm strip
- Case dimensions: 101 x 22,5 x 80 mm
Product Description
Module SIAi-8 allows to measure analog values from 8 current or voltage inputs via the RS-485 connection, with speed rate about 10 Hz (every channel).
Measurement results can be internally recalculated due to one of the available characteristics: linear, square or user definable multipoint (max. 20 points length). The SIAi-8 module is typically used in distributed control and visualization systems. Standard Modbus transmission functions are included in the SIAi-8 for changing device address or detecting type.
All SIAi-8 operating functions, available via the RS-485, can be implemented from any typical visualization software, or for instance with a suitable MultiCon CMC controller.
Product Versions
Voltage Inputs
- SKU ID: s1-siai8-0001
- Part No: SIAi-8N-001
- Input: voltage 0-10 V, 2-10 V, 0-5 V, 1-5 V
- Number of Inputs: 8
- Communication Interface: RS-485
- Transmission Protocol: Modbus RTU
- Operating Temperature: 0 to +50degC
- Power Supply: 24Vdc
Current Inputs
- SKU ID: s1-siai8-0002
- Part No: SIAi-8P-001
- Input: current 0-20 mA, 4-20 mA
- Number of Inputs: 8
- Communication Interface: RS-485
- Transmission Protocol: Modbus RTU
- Operating Temperature: 0 to +50degC
- Power Supply: 24Vdc
Connection and Operation
Connect the supply voltage to the module (+Uz, -Uz, typically 24V DC) and two wires RS-485 (A+, B-) communication interface.
Module inputs are located on the lower edge of the case (look: bottom view). Directly after power on the device is signalling its normal operation flashing green LED, marked “RUN” (about 2 times/sec.).
Short flashes of LED marked “TX/ERROR” signalize activity of RS-485 interface, and permanent light of this LED means malfunction of the device. Module makes the measurements from eight inputs in cycles.
Connection Terminals

Related Documents
Specification data sheet
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