Emerson PACSystems RX3i Programmable Automation Controller

Transistor output: such as IC694MDL740 (16 points, 0.5A, positive logic), with fast response speed, suitable for DC loads with frequent on-off.

Output modules with electronic short circuit protection (ESCP), such as IC694MDL742 (16 points, 1A) and IC695MDL765 (16 points, 2A), each output point or group has electronic short circuit and overload protection functions. When a fault occurs, it automatically shuts down and reports the status. After the fault is eliminated, it can be automatically restored, greatly improving the robustness of the system.

Intelligent output module (IC695MDL765): In addition to ESCP, it also has more advanced diagnostic functions such as wire breakage detection, switch fault detection, over temperature protection, and output pulse testing, which can comprehensively monitor the health of the output circuit.

3.3 Analog input module

Universal Analog Input (IC695ALG600): This is a powerful 8-channel universal analog input module. Each channel can be independently configured as voltage (± 10V, 0-10V, etc.), current (0-20mA, 4-20mA), thermocouple (B, C, E, J, K, N, R, S, T type), RTD (Pt100, Ni120, etc.) or resistor input. Built in Cold End Compensation (CJC), supports user-defined linearization calibration and high/low alarms.

Isolation type analog input: such as IC695ALG106 (6 channels) and IC695ALG112 (12 channels), providing isolation between channels and between channels and the system, suitable for high common mode voltage or harsh environments.

Analog inputs with HART communication, such as IC695ALG626 (16 channels) and IC695ALG628 (8 channels), can collect 4-20mA analog signals while adding HART digital communication to read multi variable data (PV, SV, TV, QV) from smart instruments. They support HART command transmission and COMMREQ function block access.

3.4 Analog output module

Basic output: such as IC694ALG390 (2-channel voltage output) and IC694ALG391 (2-channel current output), the output range can be selected through jumper wires, and the output default value can be configured (reset to zero or maintain the last state).

High density output: such as IC694ALG392 (8 channels) and IC695ALG708 (8 channels), supporting independent voltage/current configuration, with output clamp, ramp function (programmable rate of change), and advanced alarm.

Analog output with HART communication (IC695ALG728): 8 channels, supporting 4-20mA output and HART digital communication, can be used to control smart valve positioners and other devices.

3.5 Special Function Modules

High speed counter module: IC695HSC304 (8 inputs/7 outputs) and IC695HSC308 (16 inputs/14 outputs), supporting counting frequencies up to 1.5MHz, can be configured as A/B orthogonal, pulse/direction, and other counting modes, suitable for high-speed applications such as flow meters, encoders, and motion control.

Serial communication module: IC695CMM004 provides four independent, isolated RS-232/RS-485 serial ports, supporting Modbus RTU Master/Slave, serial I/O and other protocols, used to connect third-party devices such as frequency converters, instruments, barcode scanners, etc.

PROFINET communication module:

Controller module (IC695PNC001): As a PROFINET IO Controller, it manages distributed IO devices, supports MRP media redundancy, and can connect up to 128 IO devices.

Scanner module (IC695PNS001): As a PROFINET IO Device, it connects the local RX3i I/O rack to the PROFINET network and is controlled by a remote controller.

Ethernet Interface Module (IC695ETM001): Provides 10/100/1000M adaptive Ethernet ports, supports SRTP and EGD (Ethernet Global Data) protocols, and enables data exchange and programming debugging between controllers.

Redundant Memory Swap Module (IC695RMX128/228): Used to build a CPU hot standby redundant system, synchronizing data between the primary and backup CPUs through high-speed fiber optic links to achieve seamless switching.

Key points of engineering practice

Module hot plugging: The vast majority of IC695 and IC694 (after specific versions) I/O modules support plugging and unplugging while the system is powered on, greatly facilitating maintenance and expansion. However, critical modules such as CPU, power supply, and bus transmission module (LRE001) do not support hot swapping.

Noise Suppression: Chapter 2 of the manual specifically elaborates on noise minimization techniques, emphasizing the separation of noise sources (such as AC output lines) from sensitive signals (such as analog inputs) and the use of shielded twisted pair cables. For analog signals, it is recommended to use a single point grounding method, usually grounded at the signal source end.

HART communication: The HART module of RX3i supports two data acquisition methods: automatic scanning (configured as "dynamic data" or "all data") and triggering through COMMREQ command. At the same time, the system supports HART transparent transmission function, which allows remote configuration and diagnosis of on-site instruments through asset management software such as AMS device manager or FDT/DTM.

Terminal Block System: RX3i offers a variety of terminal block options, including standard 20 point pluggable terminal blocks, high-density 36 point terminal blocks, and TBQC (Terminal Block Quick Connect) system, which allows I/O modules to be connected to remote terminal blocks through prefabricated cables, simplifying wiring and replacement processes.