HARLAND SIMON H4891P5009-A PLC Machine Control Module

Description

3. Key Technical Specifications

4. Product Introduction

The Harland Simon H4891P5009-A is a legacy PC board assembly designed for industrial automation and machine control applications. Manufactured by Harland Simon—a UK-based specialist in industrial control systems—this module serves as a critical processing and interface component within legacy programmable logic controller (PLC) architectures. It is commonly found in manufacturing plants, process industries, and utility operations where Harland Simon’s control platforms were deployed.This board assembly provides reliable control functionality for legacy installations requiring spare parts to maintain operational continuity. While Harland Simon has transitioned to newer control platforms, the H4891P5009-A remains essential for facilities running established automation infrastructure. The “-A” revision suffix indicates an engineering change level, ensuring compatibility with specific system configurations. Engineers select this module for its proven field reliability and direct compatibility with existing H4891-series chassis and I/O configurations.

5. Installation & Configuration Guide

Stage 1: Pre-Installation Preparation (10 minutes)

⚠️ Safety First: Notify operations of planned downtime. Verify the control system is in a safe state. Lock out/tag out (LOTO) all power sources to the rack. Wait 5 minutes for capacitor discharge on the backplane before handling any modules.Tools Required:

• ESD wrist strap (grounded)
• PH1 Phillips screwdriver
• Digital multimeter (Fluke 115 or equivalent)
• Wire labeling tape or markers
• Smartphone/camera (for documentation)

Data Backup:

• Export all running control logic to removable media or network storage
• Document current IP addresses, node IDs, and network configurations
• Photograph all DIP switches, jumpers, and terminal wiring layouts before removal

Stage 2: Removing the Old Module (5 minutes)

1. Remove the front bezel or protective cover if present.
2. Label and disconnect all wiring from the front terminal block. Do not force connectors—they should release with gentle pressure.
3. Release the rack locking tabs (typically top and bottom) and pull the module straight out to protect backplane pins.
4. Inspect the backplane slot for bent pins, dust accumulation, or corrosion. Clean with compressed air if necessary.
5. ⚠️ Note: Keep the old module for reference until the new unit is fully operational. Do not discard until commissioning is complete.

Stage 3: Installing the New Module (8 minutes)

1. ESD prep: Verify your wrist strap is properly grounded to the rack chassis.
2. Configuration Clone (Critical): Replicate all DIP switches and jumpers from your reference photo. Pay special attention to:
   • Node address settings
   • Bus termination resistors (if applicable)
   • Communication baud rate selectors
3. Insert the H4891P5009-A into the rack slot. Push firmly until both locking tabs engage with an audible click. Ensure proper seating—no gaps between module and backplane.
4. Reattach wiring using torque-appropriate screwdriver. Do not overtighten terminal screws.

Self-Checklist:

• [ ] DIP switch positions match reference photo exactly
• [ ] All wiring secured and labeled correctly
• [ ] Rack locking tabs fully engaged
• [ ] No loose hardware inside the chassis

Stage 4: Power-On & Testing (7 minutes)

Pre-Power Check: Use your multimeter to verify no shorts on the 24V backplane rail before applying power.Power-On Steps:

1. Power up the rack only (keep field devices isolated initially).
2. Observe LED indicators on the H4891P5009-A:
   • Green RUN = Normal operation
   • Red ERR = Fault condition
   • Flashing LEDs = Boot sequence or communication handshake
3. Connect via programming software (Harland Simon proprietary tools). Verify:
   • Firmware version matches expected revision
   • Node ID is correctly recognized on the network
   • Communication handshake successful
4. Download backup logic if required.
5. Perform dry-run I/O testing before bringing field devices online.

⚠️ Troubleshooting Note: If the ERR LED remains solid red, suspect a firmware revision mismatch or incorrect DIP switch configuration. If no communication is established, verify network cabling, termination resistors, and switch port settings.

H4891P5009-A

6. Frequently Asked Questions (FAQ)

Q: Can I hot-swap the H4891P5009-A while the system is powered?

A: No. This is not a hot-swappable module. Attempting to remove or insert the board while power is applied can damage the backplane, corrupt the firmware, or destroy the processor entirely. Always perform a controlled shutdown and wait for capacitor discharge before handling. I’ve seen maintenance teams try to “quick swap” these boards during production—resulting in blown backplane traces that took entire control systems down for days.

Q: Is the H4891P5009-A obsolete, and is your stock genuinely new?

A: Yes, this model is officially obsolete from Harland Simon. Our inventory consists of new surplus stock—units manufactured during the original production run but never deployed. These are factory-sealed or tested units stored in climate-controlled conditions. We also offer refurbished units that have undergone full functional testing. Each unit ships with a detailed test report and 1-year warranty.

Q: What does the “-A” suffix mean in the part number?

A: The “-A” indicates a hardware revision level. Harland Simon used revision suffixes to track engineering changes, component substitutions, or firmware compatibility updates. The H4891P5009-A is functionally compatible with the base H4891P5009, but verify with your system documentation that your application specifically requires the “-A” revision. Some systems are sensitive to revision levels due to timing or communication protocol differences.

Q: What is the direct replacement if the H4891P5009-A is out of stock?

A: The base model H4891P5009 (without suffix) may be compatible depending on your system revision requirements. For the H4891 series, also check compatibility with H4890P-series modules, as Harland Simon often maintained cross-compatibility within product generations. If your system uses the Intella 400 platform, consult your system integrator for potential upgrade paths to newer H4893-series modules.

Q: Will I lose my programming logic when I replace the board?A: Yes—unless you have a backup.

The H4891P5009-A stores application logic in onboard memory that is lost when power is removed. You must download your program from the engineering workstation after installation. If you don’t have the original source code, extract it from the old board before removal using Harland Simon’s programming tools. I’ve seen plants lose years of accumulated control logic because someone pulled the CPU without backing up first.

Q: Why is your price lower than the OEM factory list price?

A: Harland Simon no longer manufactures this part, so “factory list price” is largely academic. Our pricing reflects the new surplus market reality—unused inventory acquired from plant closures, system upgrades, and distributor liquidations. We test every unit and pass the savings from bypassing traditional distribution channels directly to you. You’re buying proven hardware at market rates, not paying inflated prices for obsolete catalog listings.

Q: What firmware version should I request?

A: Document your current firmware revision before ordering. The H4891 series had several firmware iterations that affected communication timing. If your system runs firmware older than V2.x, a newer board may require I/O module firmware updates as well. When in doubt, request the exact revision currently installed—or be prepared to update the entire rack’s firmware suite.