ProSoft Technology 3100 Series Modules

Technical Dossier

Product Details And Specifications

ProSoft Technology 3100 Series: Comprehensive Module Range and Technical Overview

The ProSoft Technology 3100 Series represents one of the most widely deployed communication module families in heavy industrial automation. Designed as in-rack solutions for Rockwell Automation Allen-Bradley PLC-5 and SLC 500 platforms, these modules have accumulated significant installed base across global process industries including petroleum refining, chemical manufacturing, nuclear power generation, pulp and paper, and water treatment infrastructure. Their passive backplane integration and deterministic communication behavior made them the default choice for protocol bridging in facilities where replacing the host PLC was not economically viable. As of 2026, the 3100 Series is in its end-of-life phase; however, the global installed base remains substantial, and demand for spare and replacement units continues across long-lifecycle plant environments.

The Evolution of 3100 Series Architecture

The 3100 Series was introduced by ProSoft Technology in the mid-1990s as a direct response to the protocol fragmentation problem in industrial automation. At that time, Allen-Bradley PLC-5 and SLC 500 controllers dominated the discrete and process control market, but field devices increasingly required communication via Modbus RTU, Modbus ASCII, DF1, DNP3, PROFIBUS, DeviceNet, and proprietary vendor protocols. The 3100 Series addressed this by providing a self-contained protocol converter that occupied a standard I/O slot in the Allen-Bradley chassis, eliminating the need for external gateways or serial converters.

Early 3100 Series modules used RS-232 and RS-485 serial interfaces with fixed baud rates up to 115,200 bps. Firmware was stored on EEPROM and updated via serial download. Configuration was performed through ProSoft's PCB (ProSoft Configuration Builder) software utility. The modules communicated with the host PLC via the backplane using the standard Allen-Bradley block transfer mechanism, exchanging data through mapped input/output files.

As industrial Ethernet became prevalent in the 2000s, ProSoft introduced the MVI56 Series (for ControlLogix) and MVI69 Series (for CompactLogix) as the architectural successors to the 3100 platform. These newer families offered Ethernet-based configuration, expanded memory maps, and support for modern protocols such as EtherNet/IP and IEC 61850. For facilities still operating PLC-5 or SLC 500 hardware, the 3100 Series remains the only in-rack solution; no direct drop-in replacement exists on a modern platform without a full controller migration project.

3100 Series Full Catalog & Functionalities (SKU List)

The following SKUs represent the verified 3100 Series module range. Each unit is a single-slot in-rack module compatible with Allen-Bradley PLC-5 (3100-MCM, 3100-PDPMV1) or SLC 500 (3100-INUSA, 3100-MCM, 3100-DFNT) chassis unless otherwise noted.

Modbus Master/Slave Communication Modules

• 3100-INUSA: Modbus Master/Slave RTU/ASCII module for SLC 500; supports RS-232/RS-485, up to 100 nodes per port.
• 3100-MCM: Multi-protocol Communication Module; supports Modbus RTU/ASCII Master and Slave on dual serial ports for PLC-5 and SLC 500.
• 3100-MNET: Modbus TCP/IP Client/Server module; bridges Modbus TCP to Allen-Bradley backplane data files.
• 3100-MNETR: Modbus TCP/IP Client/Server with redundant Ethernet port support for fault-tolerant network topologies.

DF1 & Allen-Bradley Protocol Modules

• 3100-DF1: DF1 Full-Duplex and Half-Duplex Master/Slave communication module; used for AB-to-AB serial bridging.
• 3100-DFNT: DF1 over Ethernet (EtherNet/IP encapsulation) module; enables legacy SLC 500 systems to communicate over TCP/IP networks.
• 3100-DFCM: DF1 Communication Module with configurable Master/Slave roles and CRC error detection.

PROFIBUS Modules

• 3100-PDPMV1: PROFIBUS DP Master/Slave module for PLC-5; supports up to 125 slave devices, GSD file-based configuration.
• 3100-PDPS: PROFIBUS DP Slave module; presents the Allen-Bradley controller as a PROFIBUS slave device to a third-party master.

DNP3 & Utility Protocol Modules

• 3100-DNP: DNP3 Master/Slave module; designed for SCADA integration in electric utility and water treatment applications.
• 3100-DNPS: DNP3 Slave-only module; used where the Allen-Bradley controller must respond to a DNP3 SCADA master.

ASCII & Generic Serial Modules

• 3100-ASCII: Generic ASCII serial communication module; supports custom message parsing for barcode readers, scales, and analyzers.
• 3100-HART: HART Master module; reads HART device variables from field instruments via RS-485 multidrop wiring.

DeviceNet Modules

• 3100-DNET: DeviceNet Scanner/Adapter module; connects Allen-Bradley PLC-5 or SLC 500 to DeviceNet field device networks.

IEC 60870 & Telecontrol Modules

• 3100-IEC: IEC 60870-5-101/104 Master/Slave module; used in power utility SCADA and telecontrol applications.

Sourcing Hard-to-Find & Obsolete 3100 Series Parts

ProSoft Technology officially discontinued active production of the 3100 Series as the Allen-Bradley PLC-5 and SLC 500 platforms reached end-of-life status. Rockwell Automation discontinued the PLC-5 in 2016 and the SLC 500 in 2023. As a result, 3100 Series modules are no longer available through standard distribution channels.

DriveKNMS maintains a dedicated inventory of 3100 Series modules sourced from decommissioned plant equipment, certified refurbishers, and controlled surplus channels. Our procurement team actively tracks global availability of low-volume SKUs including the 3100-PDPMV1, 3100-DNP, and 3100-IEC, which are the most difficult to source due to their specialized protocol support and limited original production volumes.

For facilities operating under long-term maintenance contracts or regulatory frameworks that prohibit controller replacement without re-validation (pharmaceutical GMP, nuclear safety-instrumented systems), DriveKNMS provides lifecycle extension support including unit exchange programs, firmware version matching, and configuration backup services. Customers are encouraged to submit their full BOM (Bill of Materials) for a consolidated availability assessment.

Quality Control for the 3100 Series Range

Each 3100 Series module processed by DriveKNMS undergoes a structured verification protocol before shipment. The process addresses the specific failure modes documented in this module family, including backplane connector wear, EEPROM data corruption, and RS-485 transceiver degradation.

Verification steps include: visual inspection of PCB, backplane edge connector, and front-panel port connectors; powered bench test with a compatible Allen-Bradley chassis to confirm backplane communication and block transfer handshake; serial port loopback test at all supported baud rates (1200 to 115,200 bps); protocol-specific functional test using ProSoft Configuration Builder to verify firmware version, configuration read/write, and live data exchange; and final burn-in cycle of minimum 24 hours under simulated load conditions. Modules that do not pass all stages are quarantined and not offered for sale.