For FGH40KK-1200G-90G-NG/20P, EncoderWorks can configure a custom compatible replacement solution only if the 1200 PPR standard scaling, KK dual terminal-box layout, /20P hollow-shaft interface, A/B 90° phase relationship, inverted signal pairs, N reference pulse behavior, torque bracket freedom, adapter-shaft run-out, and EMC grounding remain matched. The main failure boundary is a hollow-shaft installation that runs mechanically but reports wrong speed, direction mismatch, redundant-channel deviation, or zero-reference loss because the pulse count, terminal-box mapping, 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. Because 1200 PPR is a standard pulse-rate configuration, the replacement focus is not special high-frequency operation but stable redundant speed scaling, correct A/B/N channel assignment, clean shielded wiring, and controlled hollow-shaft mounting. The KK structure should be treated as a two-terminal-box redundant layout, so both feedback paths must be checked separately before commissioning.
System Limits
The first system limit is 1200 PPR redundant scaling. If one controller channel is configured for 1024, 1000, 2048, or another pulse count, both outputs may appear electrically stable while the drive shows speed deviation or travel error. Edge-counting mode, gear ratio, direction logic, and speed-conversion factors should be confirmed on both terminal-box paths.
The second limit is dual terminal-box signal mapping. Each box must preserve A, /A, B, /B, N, and /N exactly as required by the controller or comparison system. If one phase pair is swapped, one inverted signal is omitted, or the N reference pulse is wired differently between the two boxes, the machine may fail during homing, synchronization, direction reversal, or redundant-channel comparison.
The third limit is hollow-shaft mechanics. The /20P shaft interface must fit 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 reduce bearing life and appear as pulse jitter or intermittent reference 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 1200 PPR and that the system expects 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.
Custom Compatible Solution
EncoderWorks can configure the replacement around the installed hollow-shaft and redundant terminal-box interface:
- Match 1200 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 redundant-channel agreement
Key Data
| Item | Data |
|---|---|
| Model | FGH40KK-1200G-90G-NG/20P |
| Encoder type | Incremental hollow-shaft encoder |
| Series | FGH 40 |
| Connection structure | KK, two terminal boxes / redundant version |
| Pulses per revolution | 1200 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 | 1200 PPR scaling, dual terminal-box wiring, A/B phase, N reference pulse, EMC grounding |
