Siemens QLCCM24AAN DCS Control Module Unit

Module Feature

QLCCM24AAN is a CCM+ (Critical Control Module Plus) processor card originally from Moore, now under Siemens QUADLOG / APACS+ DCS platform.

It uses Motorola 68030 core processor with onboard backup battery for RAM data retention. It supports redundant hot standby operation, built-in control function blocks, and dedicated backplane communication bus. It features heavy-duty vibration and shock resistance, long service life, and is widely used for safety-critical loop control in refining, chemical and power generation facilities.

Working principle

The module executes continuous process control logic and closed-loop regulation programs.

It exchanges real-time data with I/O modules and other controllers through the backplane bus. When primary module fails, the redundant backup module takes over control seamlessly to avoid process interruption. The onboard battery preserves configuration and runtime data during power loss.

Onboard components

Main CPU chip, battery-backed RAM, backplane communication interface, watchdog circuit, status indicator bank, heat sink assembly, edge backplane connector.

LED indicators

Front LEDs indicate power OK, active run status, fault alarm, redundant sync and communication activity.

Hardware self‑diagnosis

Built-in supervision detects CPU error, RAM checksum failure, battery low voltage, backplane communication break and watchdog timeout. Fault status and diagnostic codes can be read via system configuration software.

Programming software

Siemens APACS+ / QUADLOG configuration tool, used for control logic programming, parameter download, redundant setup and fault diagnosis.

Electrical & Process Parameters

Model:QLCCM24AAN Brand:Siemens (Moore) Device type:DCS critical control processor module Function:Executes safety and continuous process control logic for QUADLOG / APACS+ distributed control system

Mechanical & Structure

Mounting:Modulrac / Sixrac backplane rack insertion Protection class:IP20 Housing:Aluminum heat sink reinforced rack module

Environmental

Operating temperature:-25℃ ~ +70℃ Storage temperature:-40℃ ~ +85℃ Ambient humidity:5~95% non‑condensing

Certification:CE, ISA S84 capable

Status:Original Siemens legacy DCS spare

Installation

Power down the rack before inserting or extracting the module.

Align edge connector with backplane slot firmly, lock the latch, verify redundant synchronization and indicator status before restoring power.

Interface

Backplane edge connector for power, I/O bus and redundant communication.

Diagnostic

Battery low warning: Internal backup cell aging, replace battery before data loss.

Fail to synchronize: Redundant link cable loose, version mismatch between primary and backup module.

Module fault alarm: CPU / RAM hardware failure or backplane bus noise interference.

Product Brief

Siemens QLCCM24AAN control module, CCM+ processor spare for QUADLOG APACS+ DCS critical process control cabinet replacement.