FG4SS-1000G-90G-NG is a redundant FG 4 feedback encoder with dual 15-pole industrial plug connections, where EncoderWorks can configure a custom compatible replacement solution only if the 1000 PPR scaling, SS plug layout, duplicated scanning systems, A/B 90° phase relationship, inverted signal pairs, N marker behavior, shielded plug wiring, and coupling preload remain matched on both feedback paths. The main failure boundary is a machine that accepts one channel but reports speed deviation, direction disagreement, or reference mismatch because one plug pinout, phase pair, or marker path is not preserved. Typical production lead time: 15 working days.
This configuration belongs to the FG 4 optical incremental encoder platform for heavy-duty industrial environments. The 1000 PPR value belongs to the nickel-disk available pulse-rate range, so the replacement focus is stable redundant scaling rather than extreme high-frequency loading. The SS version should be handled as a redundant dual-plug encoder, not as a KK dual-terminal-box unit. Both plug-connected signal paths must be checked separately for pin assignment, shield connection, supply integrity, counter input compatibility, phase sequence, and marker-pulse interpretation.
System Limits
The first system limit is 1000 PPR redundant scaling. Both feedback paths must use the same pulse count, edge-counting mode, speed-conversion factor, and direction logic. If one counter input is set for 500, 1024, 1200, or another pulse rate, the machine may show speed deviation even when both square-wave signals look electrically clean.
The second limit is dual 15-pole plug mapping. Each plug must preserve the expected A, /A, B, /B, N, and /N relationship. If one phase pair is swapped, one inverted signal is omitted, or one marker input is interpreted differently, the controller may detect direction mismatch, homing error, or zero-reference disagreement.
The third limit is plug shielding and mechanical preload. The S/SS plug format is not the same installation boundary as a terminal box. Plug seating, shield bonding, cable strain, moisture protection, and pin mapping should be checked carefully. Coupling misalignment, axial preload, radial load, or shaft shock can reduce redundant-channel stability and appear as jitter during channel comparison.
Wiring & Installation
Before replacement, document both 15-pole plug connections separately. Record the basic channel, 90° channel, marker pulse, inverted signals, supply voltage, GND, shield connection, LED-check or diagnostic output if used, and the controller or safety input connected to each plug. Confirm whether both channels are read by one drive, two independent counters, or a safety comparison circuit, and verify the 1000 PPR scaling on both paths.
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, keep the cable away from inverter output, motor, brake, and contactor wiring, and avoid lateral cable stress at the plug. After commissioning, verify pulse count, speed scaling, direction, N marker behavior, redundant-channel agreement, plug seating, shield continuity, and signal stability through the full operating speed range.
Custom Compatible Solution
EncoderWorks can configure the replacement around the installed redundant feedback system:
- Match 1000 PPR square-wave incremental output with 0°/90° channel behavior and inverted signal pairs
- Preserve SS dual 15-pole plug 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 plug cable layout
- Review 100 kHz / 150 kHz frequency margin, shielded twisted-pair routing, plug pin mapping, bearing load, and redundant-channel agreement
Key Data
| Item | Data |
|---|---|
| Model | FG4SS-1000G-90G-NG |
| Encoder type | Heavy-duty optical incremental encoder |
| Series | FG 4 |
| Connection structure | SS redundant dual 15-pole industrial plugs |
| Pulses per revolution | 1000 PPR |
| Pulse disk class | Nickel-disk available pulse rate |
| 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 | 1000 PPR scaling, dual 15-pole plug mapping, A/B phase sequence, N marker behavior, redundant-channel agreement |
