FG4S-150G-90G-NG should be replaced as a coarse-pulse FG 4 encoder with a single 15-pole industrial plug, where EncoderWorks can configure a custom compatible replacement solution only if the 150 PPR scaling, S plug pinout, A/B 90° phase relationship, inverted signal pairs, N marker behavior, shielded plug wiring, and coupling preload remain unchanged. The main failure boundary is not counter-frequency overload; it is wrong machine scaling, direction reversal, or failed zero recovery when the low pulse count, plug pin assignment, or marker input is changed. 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 150 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 S version should be handled as a single 15-pole industrial plug encoder, not as an SS redundant dual-plug unit, K terminal-box version, or KK redundant terminal-box layout. Replacement work should focus on plug pin assignment, shield continuity, supply integrity, counter input compatibility, A/B phase sequence, marker interpretation, and mechanical alignment.
System Limits
The first system limit is 150 PPR coarse-pulse scaling. A controller configured for 250, 500, 600, 1000, or another pulse count may still receive stable A/B signals, but speed, travel, and synchronization values will be wrong. Gear ratio, edge-counting mode, speed conversion, direction logic, and machine-length calculation should be confirmed before startup.
The second limit is single-plug A/B/N mapping. The 15-pole plug must preserve A, /A, B, /B, N, and /N exactly as expected by the controller. If one phase pair is swapped, one inverted signal is omitted, or the marker input is assigned to a different pin, the machine may run normally but fail during homing, zero return, or direction reversal.
The third limit is plug shielding and mechanical preload. Even at 150 PPR, poor plug seating, cable strain, weak shield bonding, moisture at the plug, or damaged contacts can create false edges. Coupling misalignment, axial preload, radial load, or shaft shock can shorten bearing life and reduce marker-pulse repeatability.
Wiring & Installation
Before replacement, record the 15-pole plug pinout for the basic channel, 90° channel, marker pulse, inverted signals, supply voltage, GND, shield connection, LED-check or diagnostic output if used. Confirm that the receiving counter is scaled for 150 PPR and that the application does not rely on a different reference resolution.
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 repeatability, plug seating, shield continuity, and signal stability through the full operating speed range.
Custom Compatible Solution
EncoderWorks can configure the replacement around the installed counter and plug interface:
- Match 150 PPR square-wave incremental output with 0°/90° channel behavior and inverted signal pairs
- Preserve S single 15-pole industrial plug structure, N marker behavior, supply range, output level, and controller input compatibility
- 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 marker repeatability
Key Data
| Item | Data |
|---|---|
| Model | FG4S-150G-90G-NG |
| Encoder type | Heavy-duty optical incremental encoder |
| Series | FG 4 |
| Connection structure | S single 15-pole industrial plug |
| Pulses per revolution | 150 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 |
| Plug capacity | Up to 13 outputs |
| Plug protection boundary | IP55 |
| 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 | 150 PPR coarse scaling, single 15-pole plug pinout, A/B direction logic, N marker, plug shielding |
