The CI854A is a high-performance PROFIBUS DP master communication interface module, specifically designed for the ABB AC 800M controller system. It facilitates high-speed, reliable data communication between the controller and distributed peripheral devices (such as remote I/O, drives, sensors, etc.) in industrial automation systems. This module supports the PROFIBUS DP protocol and features advanced functionalities like line redundancy, module redundancy, and hot-swap capability. It is ideally suited for industrial applications with extremely high demands on system availability and communication reliability, such as process industries, power automation, and transportation control.
The CI854A is typically used in conjunction with the baseplate TP854, which provides two 9-pin female D-sub connectors for connecting to the PROFIBUS DP network with support for line redundancy. The module features DIN-rail mounting, offering high integration and ease of installation and maintenance. Its design meets the stringent requirements of industrial environments, providing excellent noise immunity and stable communication performance.
As an enhanced version of the CI854, the core advantages of the CI854A lie in its support for module redundancy (Unit Redundancy) and hot-swap functionality. In a redundant configuration, two CI854A modules (one primary, one backup) work together. If the primary module fails, the backup module can take over seamlessly, ensuring uninterrupted PROFIBUS DP network communication, thereby significantly enhancing the availability and fault tolerance of the entire control system.
2. Key Features & Functionality
PROFIBUS DP Master Functionality:
Compliant with PROFIBUS DP V0/V1 standards, supporting DP-V0 cyclic data exchange and DP-V1 acyclic data communication.
Supports DP master redundancy (CI854A only), meeting high-availability system requirements.
Supports connection of redundant slaves (Slave Redundancy).
Configurable communication speeds from 9.6 kbit/s to 12 Mbit/s.
Redundancy & High Availability:
Line Redundancy: The TP854 baseplate provides two independent PROFIBUS DP interfaces (Line A and Line B) for connecting two physically separate communication cables, achieving communication line redundancy.
Module Redundancy: Supports two CI854A modules operating in primary/backup mode. In case of primary module failure, the control system automatically switches to the backup module seamlessly and rapidly.
Hot Swap: The CI854A module can be replaced or installed without powering down the system (requires compatible rack and software configuration support), greatly facilitating maintenance and expansion.
Hardware Design:
The module connects to the AC 800M controller (e.g., PM8xx) via the CEX-Bus for power and data exchange.
Includes a built-in DC/DC converter to transform the +24 V DC power from the CEX-Bus into the required operating voltages for the module.
Galvanic isolation is implemented between the module and the PROFIBUS DP network, effectively suppressing ground loop interference and improving system noise immunity.
The TP854 baseplate is equipped with a mechanical code lock to prevent the installation of incompatible modules, ensuring correct hardware combinations.
Network Expansion Capability:
Status Monitoring & Diagnostics:
The module front panel features multiple high-brightness LED indicators for real-time display of operational status, faults, communication activity, and redundancy status, enabling rapid on-site diagnostics.
Detailed fault-finding guidelines (refer to the troubleshooting table in the documentation) assist engineers in quickly locating and resolving communication issues.
3. Hardware Structure & Components
The CI854A product package typically includes the CI854A communication module itself and the TP854 baseplate. The following is a detailed description of the main components:
CI854A Communication Module:
This is the core circuit board containing the CPU, memory, CEX-Bus interface logic, PROFIBUS DP controller, and redundancy processing unit.
The module provides status information via LEDs on the front.
It attaches and connects electrically to the TP854 baseplate via connectors on its bottom side.
TP854 Baseplate:
Serves as the mounting base and external interface board for the CI854A module.
Provides two 9-pin female D-sub connectors, labeled PROFIBUS A and PROFIBUS B, for connecting redundant PROFIBUS DP cables.
Incorporates the PROFIBUS DP interface termination resistor circuitry (controlled by switches on the connectors).
Includes a mechanical code lock to ensure only specified module types can be installed.
Connector Pin Assignment:
The pin assignment for the DB9 connectors on the TP854 is standard and clear, ensuring correct wiring.
| Pin | Designation | Description |
| 1 | Shield | Cable shield / protective ground |
| 2 | - | Not Used |
| 3 | RxD/TxD-P | Receive/Transmit Data P-line (B-line) |
| 4 | CNTR-P | Indicates Direction to Repeater (TTL) |
| 5 | DGND | Digital Ground |
| 6 | VP | +5 V, for terminating resistors |
| 7 | - | - |
| 8 | RxD/TxD-N | Receive/Transmit Data N-line (A-line) |
| 9 | DGND | Digital Ground |
Indicator (LED) Description:
The LEDs on the module front panel are vital diagnostic tools.
| Indicator | Color | Function Description |
| F(ault) | Red | Fault Indication. Set by hardware during controller reset, controlled by control software after reset. Illuminated indicates a module error. |
| R(un) | Green | Run Indication. Cleared by hardware during controller reset, controlled by control software after reset. Illuminated indicates normal module operation. |
| RxA | Yellow | Line A Receive Data Activity. Flashes for each received telegram. Appears static ON during normal communication. |
| RxB | Yellow | Line B Receive Data Activity. Flashes for each received telegram. Appears static ON during normal communication. |
| PRIM(ary) | Yellow | Primary Module Indication (CI854A only). Illuminated on the primary module in both single and redundant configurations. |
| DUAL | Yellow | Redundant Operation Indication (CI854A only). Illuminated when the CI854A is operating in a redundant configuration. |
4. Installation & Configuration Guide
1. Mechanical Installation
Mount Baseplate: First, mount the TP854 baseplate onto a standard DIN rail.
Mount Module: Align the CI854A module with the guide slots on the TP854 baseplate and press down vertically until the locking mechanism engages, ensuring the module is securely mounted. The mechanical code lock will prevent installation of incompatible modules.
2. Electrical Connection
PROFIBUS DP Cable: Must use Shielded Twisted Pair (STP) cable.
Connector: It is recommended to use PROFIBUS DP connectors with switchable built-in termination.
Wiring:
Connect the cable shield to the metal housing of the connector to ground it via the CI854A/TP854.
Data wire A (typically corresponds to green insulation or RxD/TxD-N) to connector pin 8.
Data wire B (typically corresponds to red insulation or RxD/TxD-P) to connector pin 3.
Additional Grounding: For optimal EMC performance, besides grounding via the connector, it is recommended to connect the cable shield to functional ground at both cable ends using grounding clamps.
Connection to Module: Connect the prepared PROFIBUS DP cable to the PROFIBUS A or PROFIBUS B interface on the TP854 baseplate. If line redundancy is enabled, connect a second cable to the other interface.
Termination Resistor Setting: Termination resistors must be enabled at the two outermost nodes of the PROFIBUS DP network. If the CI854A is at a network end, set the termination resistor switch on its connector to ON; if in the middle, set it to OFF.
3. Redundant Configuration Connection (CI854A)
For a redundant configuration, two CI854A modules (one primary, one backup) and two sets of PROFIBUS DP lines are required.
Mount the primary and backup modules on their respective TP854 baseplates.
Connect the two redundant cables (Line A and B) from the same PROFIBUS DP network to the corresponding interfaces on the primary and backup modules.
Enable the termination resistor (switch ON) on the interface of the module (whether primary or backup) that is at the physical end of the network.
Refer to Figure 39 in the original documentation for a detailed physical connection diagram.
4. Software Configuration
Configuration is performed in ABB's Control Builder M (CBM) engineering tool:
In the hardware configuration tree, add the CI854A module under the relevant AC 800M controller.
Set PROFIBUS DP network parameters, such as station address, baud rate, etc.
If using redundancy, enable and configure redundancy parameters for the CI854A module within CBM.
Add and configure the PROFIBUS DP slave devices to be connected.
Download the complete hardware and network configuration to the controller.
5. Fault Diagnosis & Maintenance
The CI854A provides clear LED indications and documented troubleshooting steps for user maintenance.
| Fault Symptom (LED Indication) | Possible Cause & Corrective Action |
| Both Run and Fault LEDs are OFF | Module is restarting or being configured; allow time to complete.
If condition persists and LEDs on other units on CEX-bus are also OFF:
• Check if a valid HW configuration including CI854A is downloaded to the controller.
• Check the CEX-bus fuse inside the PM8xx processor unit.
• Initiate a reset signal (INIT) from the PM8xx processor unit.
• Replace the CI854A module. |
| Fault LED is ON | Check if module is restarting; allow time.
Check CBM for any configuration fault reported from CI854A.
If status remains, initiate a reset signal (INIT) from PM8xx. If status persists after reset, replace the module. |
| RxA LED is OFF | No communication on Line A.
• Check if slaves are configured and connected to this line.
• If redundant slaves are used, check their redundancy function is working (backup slave must answer master's life list requests).
• Check all cables and connectors for damage, looseness, or poor connections. |
| RxB LED is OFF | No communication on Line B. Troubleshooting steps are the same as for RxA. |
| DUAL LED is OFF on both modules (CI854A redundant config only) | CI854A module is restarting or being configured; allow time.
Check if redundancy for this module is set within CBM and the configuration is downloaded. |
6. Typical Application Scenarios
The CI854A, with its high reliability, redundancy capabilities, and powerful PROFIBUS DP master functionality, is widely applied in the following fields:
Process Industries: Petrochemicals, pharmaceuticals, water treatment. Used to connect widely distributed remote I/O stations, flow meters, analyzers, valve positioners, etc. Redundancy ensures uninterrupted critical production processes.
Power Automation: Power plants, substations. Used to connect protection devices, smart meters, auxiliary system controllers, etc. Highly reliable communication is fundamental to grid safety and stability.
Manufacturing: Automotive, food & beverage, semiconductor production lines. Used to connect robot controllers, vision systems, smart sensors, and drive systems, supporting flexible production and fast-response control needs.
Transportation Infrastructure: Tunnel control, airport baggage handling systems. Used to connect subsystems like lighting, ventilation, fire protection, and monitoring. Redundant design meets 24/7 operational requirements.
Building Automation: Large commercial complexes, data centers. Used to connect HVAC, lighting, security systems, etc., enabling efficient, centralized monitoring and management.
