Description
Technical Specifications
| Parameter | Specification |
|---|---|
| Manufacturer | ABB |
| Model | MC91 |
| Main Part Number | HESG440588R4 |
| Associated Hardware ID | HESG112714/B |
| Product Type | Microcomputer / Central Processor Module |
| System Family | ABB Procontrol P13 |
| System Role | Central processing and control |
| System Bus | Procontrol P13 parallel bus, according to secondary documentation |
| Processor Architecture | Not independently verified |
| Program Memory | Not independently verified |
| RAM | Not independently verified |
| Power Supply | System/backplane dependent |
| Communication | Procontrol system architecture |
| Mounting | Procontrol rack |
| Firmware/PROM | Revision dependent |
| Operating Temperature | Verify against original ABB documentation |
The publicly available specifications for this legacy module are inconsistent. I would not treat the 32-bit processor, 512 KB Flash, 256 KB RAM, 24 VDC input, 16 DI/16 DO, or 500 kHz counter specifications published by some reseller pages as confirmed MC91 specifications. Those claims appear to describe a different programmable-controller architecture.
Product Overview
The ABB MC91 HESG440588R4 HESG112714/B is a legacy ABB control-system processor associated with the Procontrol P13 platform. Available technical references describe the MC91 as a microcomputer/central processor module installed within the P13 rack and responsible for processing control functions, signals, and system data.
The ABB MC91 HESG440588R4 identification should be retained together with HESG112714/B when sourcing a replacement. The HESG440588R4 designation identifies the primary board assembly/revision, while HESG112714/B is associated with the hardware assembly. Multiple current catalogs list the two identifiers together under MC91.
The belongs to an older generation of power and process control hardware, so it should not be treated like a modern AC 800M controller. Its compatibility depends on the installed Procontrol architecture, rack, bus arrangement, hardware revision, and application configuration.
MC91
Main Features & Field Considerations
Procontrol P13 processing
The strongest available technical identification places within the ABB Procontrol P13 system and describes it as a central processor/microcomputer module.
HESG revision identification
For procurement, specify the complete combination:
HESG440588R4
HESG112714/B
Do not order only “” when revision compatibility matters.
Legacy system architecture
The communicates with the surrounding Procontrol system through its native system architecture. Consequently, replacement requires checking the rack and connected modules rather than evaluating the board in isolation.
Revision control
Secondary documentation claims that earlier HESG revisions may differ from R4 and suggests checking PROM/software compatibility. That is a reasonable engineering precaution, but the claimed direct interchangeability should be verified against the plant’s original ABB documentation before treating one revision as a guaranteed substitute.
Replacement Checklist
Before replacing an ABB HESG440588R4, verify:
- Exact model:
- Main board:
- Associated hardware: HESG112714/B
- Procontrol system generation
- Rack and slot position
- Hardware revision
- PROM/application memory
- Firmware/software version
- System-bus configuration
- Existing controller configuration
- Diagnostic status
- Power/backplane condition
If the existing contains application-specific PROMs or configuration components, document their identification before removing the original board.
Specification Caution
There is a particularly high level of unreliable technical data for this part number. For example, one page labels the as a “DCS System Card” and gives 220 V / 50 kHz specifications, while another describes it as a programmable controller with 24 VDC, 16 DI, 16 DO, and a 500 kHz high-speed counter. These specifications are not consistent with the available Procontrol P13 identification and should not be published as specifications.
Recommended catalog classification:
ABB /B — Procontrol P13 Microcomputer / Central Processor Module
For procurement and replacement, the complete HESG numbers and the installed Procontrol P13 system information are the critical identifiers.
