Tosoku HC115 / HC121
Replacement guide
Replacing a Tosoku HC115 or HC121 with an Industrial Wireless MPG
The Tosoku HC115 and HC121 are the standard wired manual pulse generators fitted on thousands of Fanuc, Mitsubishi, Siemens, and Yasnac machine tools. When a Tosoku pendant fails on an active production line, shops face two options: pay $450–$800 for an OEM replacement cable/pendant, or retrofit an industrial wireless handwheel.
This guide outlines how an industrial wireless MPG drops directly onto the existing Tosoku electrical interface without machine parameter edits.
Engineering comparison
Tosoku HC series vs. direct wireless replacement
| Parameter | Tosoku HC115 / HC121 | Wireless MPG |
|---|---|---|
| Interface protocol | Quadrature A/B pulse train | Quadrature A/B pulse train |
| Encoder resolution | 100 PPR, 25 CPR cycle | 100 PPR optical disk |
| Supply voltage | Dedicated 5V, 12V, or 24V variant | 5V–24V wide-input receiver |
| Working envelope | 3.5 m before heavy recoil | 50 m clear RF line-of-sight |
| Handwheel mass | ~640 g, including hanging cable | 290 g, sealed alloy body |
| Failure mechanism | Conductor fatigue, jacket cracking | Battery exhaustion, 30-day floor |
| E-stop integration | Hardwired NC dry contact pair | NC safety relay, drops <100 ms on link loss |
Terminal reference
Landing the wireless receiver on Tosoku terminal blocks (EAHM-1540 harness)
| Signal function | Typical Tosoku wire color | Receiver terminal pin | Electrical specification |
|---|---|---|---|
| DC power (+) | Red | VCC (+5V or +12V/24V) | Connects to machine terminal strip MPG power rail |
| Common ground | Black | 0V / GND | Signal ground reference for encoder and logic |
| Phase A | Green | A+ (HA) | 5V differential line driver or single-ended TTL |
| Phase /A (Not) | White | A- (*HA) | Inverted channel for differential line noise rejection |
| Phase B | Yellow | B+ (HB) | 90° phase-shifted quadrature channel |
| Phase /B (Not) | Blue | B- (*HB) | Inverted channel for differential line noise rejection |
| Axis select X | Brown | AX1 | Dry contact closure to 0V / 24V PLC input |
| Axis select Y | Orange | AX2 | Dry contact closure to 0V / 24V PLC input |
| Axis select Z | Grey | AX3 | Dry contact closure to 0V / 24V PLC input |
| Multiplier x1 | Pink | MP1 | Scale multiplier line (0.001 mm / 0.0001 in) |
| Multiplier x10 | Violet | MP2 | Scale multiplier line (0.01 mm / 0.001 in) |
| Multiplier x100 | White/Black | MP3 | Scale multiplier line (0.1 mm / 0.01 in) |
| Emergency stop | Red/Black pair | ESTOP1 / ESTOP2 | Dual-channel NC safety circuit to machine *ESP line |
Tosoku wiring varies by machine: confirm yours free
Send your machine make and Tosoku model and we'll confirm the exact pin assignment before your unit ships.
Tosoku replacement quote
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and Tosoku model
We match the pinout and ship pre-configured, ready in one working day.