FG4K-5000G-90G-NG should be specified as a 5000 PPR glass-disk FG 4 feedback encoder, where EncoderWorks can configure a custom compatible replacement solution around the 0°/90° channel relationship, inverted signal pairs, N marker pulse, K radial terminal-box wiring, shielded twisted-pair transmission, counter-frequency margin, and coupling preload. The main failure boundary is a machine that counts correctly at low speed but develops missed edges, direction jitter, or marker instability when speed, cable noise, and mechanical preload increase together. Typical production lead time: 15 working days.
This configuration belongs to the FG 4 optical incremental encoder platform for heavy-duty industrial environments. It uses 5000 pulses per revolution, square-wave output, a 0° basic channel, a second channel electrically shifted by 90°, inverted outputs for industrial signal transmission, and an N marker pulse with inverted marker signal. The K version uses a standard radial terminal box with terminal-strip wiring, not a redundant KK dual-terminal-box structure. Replacement work should focus on controller bandwidth, 100 kHz standard frequency margin, 150 kHz special-order boundary if applicable, A/B phase accuracy, marker-pulse repeatability, shield bonding, cable-gland sealing, and shaft coupling alignment.
System Limits
The first system limit is frequency margin. At 5000 PPR, maximum usable shaft speed depends directly on the encoder output frequency limit, the counter input bandwidth, and the selected edge-counting mode. If the controller is close to its frequency limit, pulse loss may appear only during acceleration, reversal, or full-speed operation.
The second limit is A/B/N signal transmission. The controller must receive A with /A, B with /B, and N with /N as paired signals. If inverted signals are not routed through twisted pairs, common-mode interference from inverters, brakes, contactors, or motor cables can become false edges, direction errors, or marker-pulse drift.
The third limit is mechanical stability. A 5000 PPR glass-disk encoder gives finer edge spacing than lower-pulse versions. Coupling misalignment, axial preload, radial load, shaft shock, or poor centering can shorten bearing life and create rotational modulation in the pulse train.
Wiring & Installation
Before replacement, record the radial terminal-box wiring for the basic channel, 90° channel, marker pulse, inverted signals, supply voltage, GND, shield, and LED-check or diagnostic output if used. Confirm whether the installed system was designed for the standard 100 kHz frequency range or a specified 150 kHz version.
During installation, fit the coupling smoothly and do not strike the shaft or housing. Keep the encoder centered, control angular and parallel offset, and avoid axial preload. Route A-/A, B-/B, and N-/N through paired shielded conductors, bond the shield through the terminal box with a short low-impedance path, and keep the cable away from inverter output, motor, brake, and contactor wiring. After commissioning, verify pulse count, speed scaling, direction, N marker repeatability, terminal-box sealing, and signal stability at the highest operating speed.
Custom Compatible Solution
EncoderWorks can configure the replacement around the installed drive and counter system:
- Match 5000 PPR square-wave incremental output with 0°/90° channel behavior and inverted signal pairs
- Preserve N marker pulse behavior, K radial terminal-box layout, supply range, output level, and controller input compatibility
- Adapt the FG 4 mechanical envelope, shaft interface, flange or foot mounting requirement, coupling alignment, and cable-gland layout
- Review 100 kHz / 150 kHz frequency margin, shielded twisted-pair routing, EMC grounding, terminal-box sealing, bearing load, and marker-pulse repeatability
Key Data
| Item | Data |
|---|---|
| Model | FG4K-5000G-90G-NG |
| Encoder type | Heavy-duty optical incremental encoder |
| Series | FG 4 |
| Connection structure | K standard radial terminal box |
| Pulses per revolution | 5000 PPR |
| Pulse disk class | Preferred glass disk pulse rate |
| Signal output | Square wave, 0° and 90° channels |
| Inverted signals | Yes, Option G |
| Marker pulse | Option N with inverted marker signal |
| Supply voltage | 12–30 VDC |
| Output type | Differential line driver / push-pull style output |
| Frequency range | 0–100 kHz standard, up to 150 kHz if specified |
| Standard shaft | Ø11j6 × 30 mm |
| Optional shaft | Ø14j6 × 30 mm |
| Key checks | 5000 PPR counter margin, A/B phase, N marker, terminal-box shielding, coupling preload |
