A custom compatible replacement for AVM78E-021KRA0BN-1212 can be supplied by EncoderWorks with the main check placed on binary SSI terminal mapping, 12/12-bit position scaling, and Ø12 mm clamping-flange shaft fit. This model should not be treated like the servo-flange version. The shaft size may be the same, but the flange reference, coupling load, mounting face, and hazardous-area terminal handling create a different replacement boundary.
The AVM78E-021KRA0BN-1212 is an explosion-proof SSI multiturn absolute rotary encoder configuration with binary code, 12-bit singleturn resolution, 12-bit multiturn range, 10–30 VDC supply, aluminum housing execution, Ø12 mm x 25 mm solid shaft, clamping flange, KR terminal compartment, and axial exit. The controller should continue reading 4096 steps per revolution across 4096 turns.
The first failure boundary is SSI terminal assignment. Clock+ / Clock- and Data+ / Data- must remain true RS422 differential pairs. If terminal numbers, shielding, binary decoding, preset wiring, or counting-direction input are changed, the SSI frame can be present while the PLC calculates the wrong absolute position.
This replacement fails when SSI communication is present, but the PLC reads the wrong position because terminal mapping, binary decoding, 12/12-bit word length, monoflop timing, preset input, or counting direction does not match the original encoder. That is a signal-chain and parameter failure, not simply a sensing failure.
The second boundary is clamping-flange mechanics. The Ø12 mm solid shaft, coupling fit, clamping-flange centering, axial cable-entry clearance, PE grounding, and shaft load must be checked together. Flameproof terminal access must not be treated like a normal non-hazardous junction box.
The replacement decision should first confirm binary SSI format, 12-bit singleturn and 12-bit multiturn mapping, KR terminal-compartment wiring, Clock/Data differential pairs, 20 ±10 µs monoflop behavior, 10–30 VDC supply, PRESET zero-set input, counting-direction input, aluminum housing execution, Ø12 mm solid-shaft fit, clamping-flange mounting, axial exit clearance, shield grounding, flameproof cable entry, and shaft load. EncoderWorks treats AVM78E-021KRA0BN-1212 as an industrial encoder custom compatible solution where SSI terminal accuracy and clamping-flange alignment decide field reliability.
Typical production lead time: 15 working days.
Key Data
| Item | Data |
|---|---|
| Model | AVM78E-021KRA0BN-1212 |
| Encoder type | Explosion-proof multiturn absolute rotary encoder |
| Interface | SSI / RS422 |
| Resolution | 12-bit singleturn + 12-bit multiturn |
| Position range | 4096 steps x 4096 turns |
| Code | Binary |
| Supply voltage | 10–30 VDC |
| Transfer rate | 0.1–2 MBit/s |
| Housing execution | Aluminum |
| Shaft type | Solid shaft |
| Shaft size | Ø12 mm x 25 mm |
| Flange | Clamping flange |
| Connection | KR terminal compartment |
| Exit position | Axial |
| Protection focus | ATEX / IECEx flameproof enclosure, IP66 |
| Main engineering anchor | Binary SSI and clamp flange |
| Main failure boundary | Wrong terminal mapping, binary decoding error, preset fault, flange mismatch |
