FG40K-4096G-90G-NG changes the replacement boundary from a KK dual-terminal-box layout to a single radial terminal-box FG 40 configuration; EncoderWorks can configure a custom compatible replacement solution only when the 4096 PPR output, A/B 90° phase relationship, inverted channels, NG reference pulse, terminal-box wiring, EMC cable-gland shielding, and coupling preload remain unchanged. The main failure boundary is a high-pulse counter system that loses edge stability, reference repeatability, or shield continuity after the mechanical and wiring layout is changed. Typical production lead time: 15 working days.
This configuration belongs to the FG 40 heavy-duty incremental encoder platform. It uses 4096 pulses per revolution with square-wave output, basic channel 0° A and pulse channel 90° B, inverted signal pairs, and a mechanically defined NG reference pulse with inverted signal. The K version should be treated as a radial single-terminal-box encoder, not as a KK redundant or dual-box version. Replacement work should focus on pulse rate, controller input bandwidth, A/B phase accuracy, N reference timing, terminal assignment, cable-gland sealing, shield termination, and mechanical coupling alignment.
System Limits
The first system limit is 4096 PPR counter margin. This pulse rate is higher than 1000, 1024, 1200, 2000, or 2500 PPR versions, so the controller input frequency, edge-counting mode, shaft speed, and cable length must be checked together. If the counter card has limited bandwidth, the machine may count correctly at low speed but lose edges during acceleration or reversal.
The second limit is A/B/N signal integrity. The controller must receive A, /A, B, /B, N, and /N with the expected 90° phase displacement and repeatable reference-pulse behavior. If the inverted channels, phase relationship, or N pulse wiring changes, the axis may run normally but fail during homing, zero recovery, or direction checks.
The third limit is radial terminal-box EMC. The cable shield should be bonded through the terminal-box gland or a short low-impedance shielding path. Loose cable glands, long exposed drain wires, moisture in the terminal box, or routing near inverter and motor cables can create false edges and intermittent feedback faults.
Wiring & Installation
Before replacement, record the radial terminal-box wiring for A, /A, B, /B, N, /N, supply voltage, GND, shield, and any diagnostic or error output used by the machine. Confirm the cable diameter, gland sealing condition, shield contact method, and grounding strap connection.
During installation, align the coupling without force and do not strike the shaft or housing. Keep angular error, axial offset, and parallel displacement within the coupling tolerance used on the machine. Route signal and supply wiring away from inverter output, motor power lines, brakes, contactors, and solenoid valves. Tighten the cable gland and blanking plug, maintain shield continuity, and close the terminal-box cover without trapping the cable. After commissioning, verify pulse count, direction, N reference repeatability, counter margin, 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 4096 PPR square-wave incremental output with A/B 90° phase relationship and inverted channels
- Preserve NG reference pulse behavior, K radial terminal-box layout, supply voltage, output level, and counter input compatibility
- Adapt the FG 40 mechanical envelope, shaft interface, flange or foot mounting requirement, coupling alignment, and cable-gland layout
- Review counter frequency margin, shield grounding, EMC routing, terminal-box sealing, bearing load, and reference-pulse repeatability
Key Data
| Item | Data |
|---|---|
| Model | FG40K-4096G-90G-NG |
| Encoder type | Heavy-duty incremental encoder |
| Series | FG 40 |
| Connection structure | K radial terminal box |
| Pulses per revolution | 4096 PPR |
| Pulse category | Special pulse rate |
| Signal output | Square wave A/B, 90° phase |
| Inverted signals | Yes |
| Reference pulse | NG, with inverted signal |
| Supply voltage | 12–30 VDC |
| Output type | Push-pull line driver |
| Max frequency | 200 kHz |
| Standard shaft | 11j6 × 30 mm |
| Optional shaft | 14j6 × 30 mm |
| Key checks | Counter margin, A/B phase, NG reference pulse, terminal-box shielding, coupling preload |
