BMMH 58S1G24C12/13B25 Gray SSI Cable and Ø15 Blind Shaft

When replacing BMMH 58S1G24C12/13B25, the EncoderWorks custom compatible replacement should first control Gray-code SSI cable integrity, Ø15 mm blind hollow-shaft seating, and 10–30 VDC signal compatibility. This model should not be treated as the same case as the Ø12 mm blind-shaft version. The larger bore changes the mechanical check, while the SSI interface still depends on correct Clock/Data pairing, zero-input handling, and shield continuity.

The BMMH 58S1G24C12/13B25 is a magnetic SSI multiturn absolute encoder configuration with 12-bit singleturn resolution, 13-bit multiturn range, Gray code, and 10–30 VDC supply. The B25 suffix should be checked as an Ø15 mm blind hollow-shaft, radial cable, IP65 execution against the original label and mounting drawing before production.

The first failure boundary is blind hollow-shaft seating. A blind hollow shaft is not a through bore. The machine shaft must enter to the correct depth, stay inside the clamping zone, and avoid bottoming inside the encoder. If the shaft is inserted too deeply or too shallowly, the bearing system can carry axial preload or the clamping force can act in the wrong place.

This replacement fails when SSI communication is stable, but the machine position becomes unreliable because the Ø15 mm blind shaft is bottomed, under-inserted, or loaded by torque support misalignment. The fault may look electrical, while the first failure is mechanical seating.

The second boundary is SSI cable pairing. Clock+ / Clock- and Data+ / Data- must remain differential pairs through the cable route. If a junction box or cabinet extension breaks pair structure, the controller may read shifted words or intermittent position values. Data termination and shield grounding should be checked at the receiver side.

Zero setting must be protected during installation. A wrong zero pulse can shift the electrical reference without any mechanical movement. Gray-code interpretation must also match the controller; a clean SSI word still fails if the PLC expects binary data or a different bit order.

The replacement decision should first confirm B25 suffix execution, Ø15 mm blind hollow-shaft fit, insertion depth, IP65 requirement, radial cable assignment, 10–30 VDC SSI supply, 12-bit singleturn and 13-bit multiturn mapping, Gray code setting, Clock/Data differential pair wiring, data termination, zero input behavior, shield grounding, torque support, and shaft seating. EncoderWorks treats BMMH 58S1G24C12/13B25 as an industrial encoder custom compatible solution where SSI cable integrity and Ø15 blind-shaft mechanics decide field reliability.

Typical production lead time: 15 working days.

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