For machines using FGH40KK-2000G-90G-NG/20P, EncoderWorks can configure a custom compatible replacement solution only if the 2000 PPR standard scaling, KK dual terminal-box layout, /20P hollow-shaft fit, A/B 90° phase relationship, inverted signal pairs, N reference pulse behavior, adapter-shaft run-out, torque bracket freedom, and EMC grounding remain unchanged. The main failure boundary is a hollow-shaft feedback system that produces clean pulses but reports wrong speed, travel error, redundant-channel deviation, or zero-reference loss because the 2000 PPR scaling, terminal-box wiring, bore fit, or torque support has changed. Typical production lead time: 15 working days.
This model belongs to the FGH 40 incremental hollow-shaft encoder platform. The 2000 PPR value is a standard pulse-rate configuration, so the replacement focus is stable metric-style scaling, dual terminal-box agreement, correct A/B/N channel assignment, shielded wiring continuity, and controlled hollow-shaft mounting. Compared with 2048 PPR versions, this configuration should not be substituted by a near-value encoder unless the controller scaling and machine conversion factors are changed accordingly.
System Limits
The first system limit is 2000 PPR scaling. If one controller channel is configured for 2048, 1200, 2500, 4096, or another pulse count, both terminal-box outputs may look electrically stable while speed, travel, and synchronization values become wrong. Edge-counting mode, gear ratio, speed conversion, direction logic, and any metric travel calculation should be confirmed on both feedback paths.
The second limit is KK dual terminal-box agreement. Each terminal box must preserve A, /A, B, /B, N, and /N exactly as required by the controller or redundant comparison circuit. If one phase pair is swapped, one inverted output is omitted, one shield reference is different, or the N reference pulse is wired differently between boxes, the machine may fail during homing, direction reversal, or redundant-channel comparison.
The third limit is hollow-shaft mechanical stability. The /20P interface must fit the prepared shaft without forcing, and the torque bracket must remain free at the link heads. Excessive adapter-shaft run-out, axial preload, radial load, shaft shock, or a bound torque arm can shorten bearing life and appear as pulse jitter or intermittent reference-pulse errors.
Wiring & Installation
Before replacement, document both terminal-box connections separately. Record supply voltage, GND, shield connection, A/B/N signal sequence, inverted outputs, and any diagnostic output used by the control system. Confirm that both counter inputs are scaled for 2000 PPR and that both paths expect the same 0°/90° phase sequence and N reference pulse behavior.
During mechanical installation, clean the customer shaft, centering surface, bolting faces, and fastening threads. Align the adapter shaft carefully, avoid hammering the encoder, and make sure the hollow-shaft device is not pulled into position by force. The torque bracket should support housing reaction torque without creating bearing preload.
For EMC stability, use shielded signal cables, keep feedback wiring away from inverter, motor, brake, contactor, and power cables, and bond the grounding strap to a nearby low-impedance bare-metal grounding point. Cable glands and blanking plugs must be tightened properly, and cable strain must not pull sideways on the terminal-box entries. After commissioning, verify pulse count, direction, reference pulse, dual-box agreement, shielding continuity, and stable operation through the required speed range.
Custom Compatible Solution
EncoderWorks can configure the replacement around the installed hollow-shaft and redundant terminal-box interface:
- Match 2000 PPR square-wave incremental output with 0°/90° channel behavior and inverted signal pairs
- Preserve KK dual terminal-box structure, N reference pulse behavior, supply range, output level, and redundant-channel compatibility
- Adapt the FGH 40 hollow-shaft /20P mounting interface, adapter-shaft fit, torque bracket position, sealing boundary, and cable-gland orientation
- Review 200 kHz counter margin, shielded wiring, terminal-box mapping, grounding strap, bearing load, and dual-channel agreement
Key Data
| Item | Data |
|---|---|
| Model | FGH40KK-2000G-90G-NG/20P |
| Encoder type | Incremental hollow-shaft encoder |
| Series | FGH 40 |
| Connection structure | KK, two terminal boxes / redundant version |
| Pulses per revolution | 2000 PPR |
| Pulse-rate class | Standard pulse rate |
| Signal output | Square wave, 0° and 90° channels |
| Inverted signals | Yes, G output configuration |
| Reference pulse | NG, N reference pulse with inverted signal |
| Hollow-shaft interface | /20P |
| Supply voltage | 12–30 VDC |
| Output type | Current-limited, short-circuit-proof push-pull line driver |
| Maximum frequency | 200 kHz, higher on request |
| Protection class | IP65 standard, IP66 versions depending on sealing |
| Mechanical checks | /20P shaft fit, adapter-shaft run-out, torque bracket freedom, bearing load |
| Key replacement checks | 2000 PPR scaling, dual terminal-box agreement, A/B phase, N reference pulse, EMC grounding |
