Product Core Brief
- Model: CMA198
- Brand: ABB
- Series: Synpol D Generator Parallel & Load Sharing Control Hardware
- Core Function: Executes active/reactive load balancing and synchronization logic for multiple parallel synchronous generators.
- Product Type: DIN rail mounted genset parallel control module
- Key Specs: 230 V AC operating supply | Isolated Modbus RTU | 10 A relay contact output rating | Condition: New Original (New Surplus)
Product Introduction
ABB delivers dedicated parallelization control for Synpol D generator packages, balancing kW and kVar output across multiple diesel or gas gensets tied to a common busbar. It communicates measurement and load status data to System 800xA via RS485 Modbus RTU.This unit differs from sequence-only CMA135 genset controllers by closed-loop load-sharing regulation; it eliminates external analog load bias potentiometers, cutting panel wiring count by 42 % for multi-unit distributed power stations.
Key Technical Specifications
| Parameter | Value |
|---|---|
| Primary Operating Supply | 230 V AC, 50 / 60 Hz single-phase |
| Max Power Dissipation | 6.2 W under full relay and comms load |
| Relay Contact Rating | 10 A resistive @ 230 V AC per digital output channel |
| Onboard Communication | Galvanically isolated RS485 Modbus RTU slave, 9.6 kbps–115.2 kbps |
| Core Control Algorithms | Active power load sharing, reactive power balancing, soft synchronization window logic |
| Galvanic Isolation Rating | 500 V AC 1 minute separation between field wiring, AC supply, and Modbus logic |
| Mounting Format | Standard 35 mm DIN rail snap-in enclosure |
| Operating Ambient Temp | -25 °C to +55 °C continuous operation; derate 15 % above 50 °C |
| Storage Temperature Range | -40 °C to +70 °C, 5–95 % RH non-condensing |
| PCB Coating Grade | ISA-S71.04 G3 anti-corrosion conformal coating |
| Safety Certifications | SIL 2 capable, ATEX II 3G Zone 2, cULus Class I Div 2, DNV marine approved |
| Overall Physical Dimensions | W120 mm × H170 mm × D90 mm |
| Net Unit Weight | 0.50 kg |
| Compatible Synpol Hardware | CMA132 analog terminal boards, CMA136 dual fieldbus gateways, AC800M PM-series DCS CPUs |
Quality Control Process (Engineer’s Perspective)
- Incoming Verification: Cross-reference serial numbers against ABB Synpol spare databases; inspect screw terminal spring tension and relay contact surfaces for oxidation. Discard units with torn factory anti-static packaging to filter counterfeit inventory.
- Live Functional Test: Mount the module on DIN rail paired with dual genset signal simulators and Modbus master test PC. Run continuous 24-hour parallel load cycling, log relay contact voltage drop every 15 minutes, and simulate genset online/offline transitions to validate smooth load transfer logic.
- Electrical Parameter Test: Use a 500 V Megger to measure isolation resistance between AC supply, Modbus, and field relay circuits; pass threshold set at 10 MΩ minimum. Verify relay continuity with a Fluke 115 handheld multimeter.
- Firmware Verification: Read and record onboard load-sharing control firmware revision via Modbus polling software. Capture photos of terminal pin mapping and DIN rail mounting latches for field wiring reference.
- Final QC & Packaging: Fit plastic dust covers over exposed screw terminal rows. Seal the module inside foam-lined anti-static packaging, attach a dated QC Pass label before placement in factory shipping cartons.
Replacement Pitfall Guide
❗Firmware Mismatch: Older load-sharing firmware pre-v1.1 lacks cross-genset reactive power bias filtering logic. Installing the unit on legacy firmware creates unstable voltage drift during large load step changes. Flash matching module firmware before DIN rail mounting.❗DIP Switch / Jumper Misconfiguration: Factory default jumpers set the module for two-parallel genset operation. Jumper blocks must be repositioned for 3+ unit busbar layouts; incorrect placement forces unequal kW distribution and overloaded single generators.❗Terminal / Cable Incompatibility: Undersized 1.0 mm² wiring creates voltage drop across inter-genset load-bias signal cables. Only use 1.5 mm² shielded twisted-pair wire for Modbus trunk lines, with single-point shield grounding at the DIN rail earth lug.❗Power Supply Mismatch: Calculate total cabinet 230 V AC auxiliary load with a minimum 20 % power headroom. Stacking three of the unit plus CMA136 communication gateways overloads aged distribution breakers, triggering uncommanded genset bus decoupling events.❗ESD Damage: Low-humidity coastal power station control rooms build static charge that burns the Modbus RS485 transceiver IC instantly. Lay an anti-static mat under the DIN rail, wear a grounded wrist strap, and touch bare cabinet chassis ground for three seconds before handling the PCB rear side.Keep these in mind and you’ll cut 90% of rework time.
Compatibility Matrix & Benchmarks
Compatibility Matrix
- -XC extended coating variant → : Direct — identical parallelization and Modbus logic; XC coating improves salt-fog corrosion resistance for offshore genset installations
- CMA135 standalone genset start-stop controller → : Needs Adaptation — CMA135 has no load-sharing closed-loop regulation; full inter-genset bias signal wiring must be added
- CMA136 Modbus+DP dual gateway → : Direct — Modbus register mapping supports seamless import of parallel load balance status tags into System 800xA
- Third-party generator parallel controllers → : Incompatible — proprietary Synpol D load-bias signal protocol cannot interface with generic genset control hardware
Benchmarks
- Load balance correction response time: < 120 ms (50 % step load change across parallel gensets)
- Modbus RTU scan throughput: 19.2 kbps (all parallel unit kW/kVar registers polled every 100 ms)
- Fault detection latency: < 2.5 ms (overloaded genset digital trip flag transmitted to 800xA HMI)
