Description
- Model: GE Horner HE700GEN100C
- Brand: GE Fanuc / Horner APG
- Series: Series 90-70 (VME-based system)
- Core Function: Genius Bus Interface / Communications Co-processor
- Product Type: Communication Module
- Key Specs: Supports Genius Bus protocol, high-speed VME backplane interface, 153.6 Kbaud
HORNER HE700GEN100C
Key Technical Specifications
- Module Rev: C (Improved logic timing for higher stability)
- Protocol Support: GE Genius Bus (Global Data and Datagrams)
- Data Rate: Standard 153.6 Kbaud (standard) or 76.8 Kbaud (extended distance)
- Bus Loading: Supports up to 31 Genius devices per bus
- VME Interface: Standard 90-70 high-speed backplane integration
- Power Draw: Typically 1.2 A at +5 V DC from the backplane
- Isolation: Optical isolation between Genius Bus and VME logic
- Diagnostic LEDs: OK, Comm, and Fault indicators on the front panel
- Configuration: Set via Logicmaster 90 or Proficy Machine Edition (PME)
Application Scenarios & Pain Points
The HE700GEN100C is a specialized bridge. In many older automotive and steel plants, the Series 90-70 PLC acts as the master brain, but the actual sensors and valves are miles away on a “Genius Bus” network. If this Horner module fails, the brain loses its “nervous system.” The biggest headache for engineers today is that Genius Bus is a legacy protocol. Replacing a failed module often feels like a race against time before the plant’s older wiring starts causing secondary reflections and noise issues.
1. Automotive Assembly Lines
Used in legacy 90-70 racks to control distributed Genius I/O blocks across large conveyor systems where high-speed synchronized data is required.
2. Steel & Heavy Industry
Found in harsh environments where the Genius Bus’s robust error-checking and long-distance capabilities are leveraged for motor control centers.
3. Redundant Control Systems
Common in mission-critical setups where dual 90-70 CPUs share Genius Bus data for hot-standby redundancy.
Case Study: The “Intermittent Comm” Mystery
Background: A paper mill in the Southern US was using a 90-70 system to manage a wet-end process. They started seeing “Bus Off” errors that would happen once or twice a shift, forcing a full system reset.
The Problem: The site team suspected the Genius cables, but after replacing 500 feet of wire, the problem remained. Our analysis suggested the HE700GEN100 module’s transceiver was “leaking” noise back into the logic side. The old Rev A board simply couldn’t handle the EMI (Electromagnetic Interference) anymore.
The Solution: We supplied a Rev C HE700GEN100C. This revision includes enhanced filtering on the transceiver circuit. Before shipping, we ran a 48-hour loopback test using a 150-ohm terminator to ensure zero packet loss under load.
The Result: After swapping to the Rev C board, the “Bus Off” errors vanished. The mill hasn’t had a comm-related trip in over 6 months.
- Avoided Loss: Each reset cost 45 minutes of production, roughly $12,000 in lost throughput.
- Takeaway: Revision matters. The “C” revision is significantly more “bulletproof” in electrically noisy environments than the older A or B versions.
HORNER HE700GEN100C
Compatible Replacement Models
| Original Model | Replacement Model | Compatibility | Key Differences | Workload |
| HE700GEN100A | HE700GEN100C | ✅ Direct | Rev C has better noise immunity | Plug & Play |
| IC697BEM731 | HE700GEN100C | ⚠️ Software | GE Native vs. Horner Version | Check PME config |
| IC693 series | HE700GEN100C | ❌ Incompatible | 90-30 vs. 90-70 racks | Totally different bus |
Engineer’s Advice: Honestly, I’ve found that the Horner HE700 series is often more reliable than the original GE BEM731 modules in high-heat racks. However, make sure you check your baud rate jumpers. If the new board is set to 153.6K but your field devices are at 76.8K, nothing will talk, and you’ll spend hours chasing a “faulty” board that’s just misconfigured.
Troubleshooting Quick Reference
| Symptom | Possible Cause | HE700 Related? | Quick Check | Action |
| “OK” LED is Off | Power/Internal Fault | ✅ High | Check +5V backplane voltage | Replace module |
| “COMM” LED Flickers Red | Bus Noise/Reflections | ⚠️ Medium | Check for 75Ω/150Ω terminators | Verify shielding/grounding |
| PLC Configuration Error | Wrong Slot / Wrong ID | ✅ High | Verify Slot # in PME/Logicmaster | Correct the hardware config |
| “I/O Forced” Warning | Software Override | ❌ Low | Check software force table | Not a hardware issue |
Expert Setup Tips:
- The 150-Ohm Rule: ❗ Don’t forget the terminators! Genius Bus is a daisy-chain. If you don’t have a resistor at both the first and last device, the signal reflects and kills the communication. Most “dead” HE700 boards I see are actually just working in a poorly terminated network.
- Firmware Compatibility: If you are using an extremely old 90-70 CPU (Standard VME), ensure your CPU firmware is at least version 6.0 to support the extended features of the Horner module.
- Static Shielding: When installing, ensure the module’s faceplate makes good contact with the rack’s ground rail. Static buildup on the Genius cable can jump to the logic board if the ground path is poor.
