C-FG40KK-1024G-90G-NG-S should be handled as a customer-specific FG40KK overspeed-feedback configuration, where EncoderWorks can configure a custom compatible replacement solution only if the 1024 PPR output, A/B 90° phase relationship, inverted channels, NG reference pulse, Option S switching behavior, KK dual-terminal-box wiring, EMC grounding, and coupling preload are preserved together. The main failure boundary is a replacement that produces correct A/B pulses but changes the reference pulse, overspeed trip logic, terminal separation, or mechanical signal stability. Typical production lead time: 15 working days.
This configuration belongs to the FG 40 heavy-duty incremental encoder platform. It uses 1024 pulses per revolution with square-wave output, basic channel 0° A and pulse channel 90° B, inverted signals, a mechanically defined NG reference pulse with inverted signal, and Option S electronic overspeed switching. The KK structure should be treated as a dual terminal-box or redundant-style arrangement, especially where one wiring path is used for pulse feedback and another is used for overspeed or service separation. Replacement work should focus on pulse rate, A/B phase accuracy, N reference repeatability, overspeed switching points, output voltage level, counter input compatibility, shield termination, and coupling alignment.
System Limits
The first system limit is A/B/N signal behavior. The controller must receive A, /A, B, /B, N, and /N with the expected 90° phase displacement and reference-pulse timing. If the inverted channels, N pulse position, or direction relationship changes, the machine may count during normal running but fail during homing, zero recovery, or direction reversal.
The second limit is Option S overspeed switching. This option must be checked as part of the machine protection chain, not only as an auxiliary output. Switching thresholds, output wiring, response behavior, and terminal assignment must match the existing drive or safety logic. If the overspeed function changes while the incremental channels remain correct, the machine can lose a protection boundary.
The third limit is mechanical and EMC installation. Coupling misalignment, axial preload, radial load, weak shield bonding, or signal wiring routed near inverter and motor cables can degrade edge quality and shorten bearing life. The dual terminal-box layout also needs to be preserved if the installed machine separates feedback, diagnostics, or overspeed wiring.
Wiring & Installation
Before replacement, record the terminal-box wiring for A, /A, B, /B, N, /N, supply voltage, GND, shield, error output if used, and Option S switching outputs. Confirm whether the C-prefix represents a customer-specific wiring, nameplate, cable-gland, terminal, or configuration requirement.
During installation, align the coupling without force and do not hammer 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, motor, brake, contactor, and solenoid cables. Use low-impedance grounding, maintain shield continuity, and seal the terminal boxes and cable glands before startup. After commissioning, verify pulse count, direction, N reference repeatability, overspeed switching response, terminal-box separation, and signal stability across the operating speed range.
Custom Compatible Solution
EncoderWorks can configure the replacement around the installed counter and overspeed system:
- Match 1024 PPR square-wave incremental output with A/B 90° phase relationship and inverted channels
- Preserve NG reference pulse behavior, Option S overspeed switching, KK dual-terminal-box layout, supply voltage, and output level
- Adapt the FG 40 mechanical envelope, shaft interface, flange or foot mounting requirement, coupling alignment, and cable-gland layout
- Review customer-specific C-prefix requirements, counter margin, shield grounding, EMC routing, terminal separation, bearing load, and protection logic
Key Data
| Item | Data |
|---|---|
| Model | C-FG40KK-1024G-90G-NG-S |
| Base configuration | FG40KK-1024G-90G-NG-S |
| Encoder type | Heavy-duty incremental encoder |
| Series | FG 40 |
| Connection structure | KK dual terminal box / redundant-style version |
| Pulses per revolution | 1024 PPR |
| Pulse category | Standard pulse rate |
| Signal output | Square wave A/B, 90° phase |
| Inverted signals | Yes |
| Reference pulse | NG, with inverted signal |
| Option | S electronic overspeed switch |
| 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 | C-prefix requirement, A/B phase, N pulse, overspeed switch, terminal-box wiring, EMC grounding |
