For FGH4KK-1200G-90G-NG/20P, EncoderWorks develops a custom compatible replacement solution for heavy-duty incremental feedback where 1200 PPR scaling, A/B 90° quadrature, NG reference-pulse behavior, dual terminal-box wiring, shield continuity, and 20 mm hollow-shaft fit must remain stable at the installed counter. The failure boundary is not a fieldbus address or an absolute position word, but wrong pulse scaling, missed direction edges, reference-pulse mismatch, redundant-output inconsistency, output-driver incompatibility, ground noise, hollow-shaft runout, and torque-reaction movement. Typical production lead time: 15 working days.
This model is used where the controller reads speed, direction, and relative position from A/B incremental channels and uses the NG reference pulse for homing, indexing, or machine synchronization. A compatible replacement must preserve the 1200 pulses per revolution, 90° channel separation, reference-pulse location, inverted reference requirement, output level, dual terminal-box assignment, shield path, 20P bore interface, and heavy-duty mounting boundary.
System Limits
The first system boundary is the 1200 PPR counter interface and dual-output wiring expectation. FGH4KK-1200G-90G-NG/20P must be checked against the controller’s edge evaluation mode, speed scaling, maximum input frequency, expected A/B direction, reference-pulse width, output-driver type, cable length, and inverted-signal requirement. If the replacement is supplied as 1024 PPR, 1000 PPR, 4096 PPR, or another nearby resolution, the encoder may still generate clean pulses while the controller calculates the wrong travel, speed, or index position. If the dual terminal-box boundary is not preserved, duplicated or redundant channels may disagree, lose the same reference point, or introduce ground-loop noise between cable paths.
The second boundary is the 20 mm hollow shaft and EMC installation. Dual terminal-box wiring, 0 V reference, shield bonding, cable routing, housing ground, and cable-entry separation must be treated as part of the measurement circuit. A correct encoder can still fail if one shield path is high impedance, one terminal box loses PE continuity, signal cables are routed beside brake or inverter wiring, or the 20 mm bore is clamped with eccentric load. Mechanical checks should include bore fit, shaft runout, axial movement, torque-reaction restraint, vibration, and bearing load.
Wiring & Installation
Before replacement, confirm the complete installed model code, 1200 PPR requirement, A/B phase relationship, NG reference-pulse use, inverted reference requirement, output circuit, supply voltage, counter input frequency, dual terminal-box layout, cable entry direction, shield termination method, and 20 mm hollow-shaft dimension. This FGH4KK version should not be inferred from ordinary FGH4K variants because the terminal-box count, grounding path, redundant wiring behavior, and cable-routing boundary are different.
During installation, verify A, B, reference, inverted reference if used, supply, 0 V, shield, housing ground, and both terminal-box paths before powering the system. Keep signal cables away from motor, brake, SCR, and VFD wiring, and avoid using the cable shield as a load-carrying ground conductor. The hollow shaft must sit concentrically on the machine shaft, and the torque-reaction element should stop encoder-body rotation without forcing the bearing system. Eccentric preload can become phase jitter, bearing wear, or poor reference-pulse repeatability.
Custom Compatible Solution
- Match 1200 PPR incremental feedback, A/B 90° quadrature, NG reference-pulse behavior, and controller counter expectations
- Preserve output-driver compatibility, dual terminal-box wiring, supply reference, inverted-signal requirement, shield paths, and grounding continuity
- Adapt the 20 mm hollow shaft, heavy-duty housing, bore fit, torque-reaction boundary, cable entries, and machine-side mounting geometry
- Review counter scaling, speed calculation, redundant signal consistency, homing behavior, EMC exposure, shaft runout, vibration, and commissioning checks before shipment
Key Data
| Item | Data |
|---|---|
| Model | FGH4KK-1200G-90G-NG/20P |
| Encoder type | Heavy-duty hollow-shaft incremental encoder |
| Feedback type | Incremental A/B with reference pulse |
| Pulse count | 1200 PPR |
| Phase relationship | A/B, 90° quadrature |
| Reference pulse | NG reference pulse with inverted signal requirement |
| Shaft interface | 20 mm hollow shaft / 20P bore |
| Connection boundary | Dual terminal-box wiring requires confirmation against installed version |
| Output circuit | Requires confirmation against controller input |
| Supply voltage | Requires confirmation against installed version |
| Key system checks | Counter scaling, speed calculation, edge evaluation, A/B direction, NG reference pulse, inverted signal, redundant wiring, shield grounding |
| Key mechanical checks | Bore fit, shaft runout, torque reaction, axial movement, vibration, bearing load |
| Replacement focus | 1200 PPR scaling, dual terminal-box grounding, NG reference behavior, 20 mm hollow-shaft stability |
