Model Explanation

B875 = 8-channel analog input series; 101 = First-generation old version, fixed single-ended, factory-set 4-20mA current

100: Old version multi-range code single-ended universal model

101: Old version fixed 4-20mA single-ended, without code, cannot change voltage

0XX: Second-generation revised PCB hardware Technical Specifications

Channels: 8-channel hardware-fixed single-ended input, no differential circuit, cannot be changed to differential wiring; 250VAC isolation between channels, 300VAC withstand isolation on the backplane

Fixed range: Only 4-20mA DC input, built-in onboard 250Ω precision sampling resistor, does not support 0-5V/1-5V/±10V voltage acquisition, no range switching hardware

Input impedance: Current loop fixed at 250Ω, voltage input impedance 1MΩ (this model does not enable)

AD conversion: 12-bit analog-to-digital conversion, full-scale 25°C accuracy ≤ ±0.12% FS

Backplane power consumption: Rack 5VDC power supply, rated 380mA, no need for external on-site power supply

Dimensions: 51 (W) × 203 (H) × 280 (D) mm, net weight 0.86kg

Status indicator lights: RUN green running light, OVER over-range red light, UNDER under-range / open-circuit red light

Environmental parameters: Operation 0-60℃, storage -40-85℃, humidity ≤ 80% RH without condensation, IP20 protection

Interface and matching base

Universal original screw terminal base: AS-8535-000, compatible with the entire B875-001/100 series base. Core function

Designed specifically for the collection of 4-20mA pressure, level and flow transmitters in two-wire system. Single-ended wiring for collection. When there is a break in the line, the UNDER red light will illuminate. When the signal is greater than 20mA, the OVER alarm will be triggered. It is incompatible with voltage-type sensors. Applicable scenarios

Renovation of the old refining and power generation Modicon984 system. All on-site points are 4-20mA transmitters, with short wiring distances and no strong electromagnetic interference at the acquisition positions.

Operation and Maintenance

The module is directly inserted into the I/O slot of the 800 rack. There are no range / single differential dial jumpers. The hardware is locked to 4-20mA; voltage-type instruments are not allowed to be connected; when the red light is on, it is necessary to first check for circuit breakage or transmitter failure; it can be used in the same rack with the entire series of B875 cards (001/002/011/012/100).