FG4KK-16384G-90G-NG is a non-standard high-pulse redundant FG 4 replacement case, where EncoderWorks can configure a custom compatible replacement solution only if the 16384 PPR scaling, KK dual-terminal-box structure, duplicated scanning outputs, A/B 90° phase relationship, inverted signal pairs, N marker behavior, shielded twisted-pair routing, and coupling preload are treated as one system boundary. The main failure point is not only pulse-count mismatch; it is a redundant feedback system that loses synchronization, counter-frequency margin, or marker consistency after one channel, one terminal box, or one signal pair is changed incorrectly. Typical production lead time: 15 working days.
This configuration belongs to the FG 4 optical incremental encoder platform for heavy-duty industrial environments. The KK version should be handled as a redundant-style encoder with two terminal boxes and two evaluation/scanning systems, not as a standard K single-terminal-box encoder. Because 16384 PPR is above the listed preferred glass-disk pulse rates for FG 4, replacement should be treated as a special high-pulse configuration requiring careful confirmation of output frequency, controller bandwidth, terminal assignment, marker logic, and mechanical stability.
System Limits
The first system limit is the 16384 PPR frequency boundary. FG 4 square-wave output is normally rated for a 0–100 kHz frequency range, with 150 kHz only when specified. At 16384 PPR, the usable shaft speed becomes much lower than with 1000, 4096, or 8192 PPR. If the drive, PLC counter, or safety channel is close to its input-frequency limit, missed edges may appear only during acceleration, braking, or reversal.
The second limit is redundant signal consistency. In a KK configuration, each system must keep the correct A, /A, B, /B, N, and /N relationship. If one terminal box is wired differently from the other, the machine may show disagreement between channels, false speed deviation, direction mismatch, or reference-position inconsistency. Marker-pulse displacement between redundant systems must also be considered during commissioning.
The third limit is mechanical and EMC stability. At 16384 PPR, small shaft runout, coupling preload, vibration, cable noise, or shield discontinuity can become visible as edge jitter. A-/A, B-/B, and N-/N should be routed as paired shielded conductors, with short low-impedance shield bonding at the terminal boxes.
Wiring & Installation
Before replacement, document both KK terminal boxes separately. Record each channel assignment, supply, GND, shield, LED-check or diagnostic output if used, and the controller or safety input connected to each system. Confirm whether both channels are read by the same controller, by separate counters, or by a safety comparison circuit.
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 both sets of A-/A, B-/B, and N-/N through shielded twisted pairs, avoid routing near inverter output and motor cables, and keep terminal-box sealing intact. After commissioning, verify pulse count, speed scaling, direction, N marker behavior, redundant-channel agreement, terminal-box sealing, and signal stability at the highest operating speed.
Custom Compatible Solution
EncoderWorks can configure the replacement around the installed redundant feedback system:
- Match 16384 PPR square-wave incremental output with 0°/90° channel behavior and inverted signal pairs
- Preserve KK dual-terminal-box structure, redundant channel separation, N marker behavior, supply range, and output level
- 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 redundant-channel agreement
Key Data
| Item | Data |
|---|---|
| Model | FG4KK-16384G-90G-NG |
| Encoder type | Heavy-duty optical incremental encoder |
| Series | FG 4 |
| Connection structure | KK redundant dual terminal boxes |
| Pulses per revolution | 16384 PPR |
| Pulse disk class | Special high-pulse configuration, on request |
| Signal output | Square wave, 0° and 90° channels |
| Inverted signals | Yes, Option G |
| Marker pulse | Option N with inverted marker signal |
| Redundant structure | Two scanning/evaluation systems |
| 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 | 16384 PPR frequency margin, KK channel agreement, N marker behavior, terminal-box shielding, coupling preload |
