The safety circuit is one of the most important parts of an elevator control system. It connects multiple safety devices throughout the shaft, car, machine room, landing doors, and car doors. If any required safety signal is interrupted, the elevator controller can stop operation to prevent unsafe movement.
For HITACHI elevator systems, understanding the basic safety circuit structure and the relationship between safety devices and fault codes can help maintenance technicians locate problems more efficiently.
This guide provides an overview of the commonly referenced HITACHI safety circuits, electrical connections, and fault codes.
HITACHI Elevator Safety Circuit Overview
The HITACHI elevator safety circuit can generally be divided into several sections:
Hoistway safety circuit
Car-top safety circuit
Machine-room safety circuit
Landing door lock circuit
Car door lock circuit
Deceleration switch circuit
Each section performs a different safety monitoring function. The controller continuously checks these signals during elevator operation.
1. Hoistway Safety Circuit
The main hoistway-related safety signals include:
XL2–XL1: Upper terminal limit
XL12–XL11: Lower terminal limit
XR1.1–XR1.2: Pit safety circuit
XL4–XL3: Upper limit switch
XL14–XL13: Lower limit switch
These devices help monitor the elevator’s position and travel limits inside the hoistway.
2. Car-Top Safety Circuit
The car-top circuit includes safety devices such as the safety gear and emergency exit.
Y2.19–Y2.20: Safety gear and emergency exit safety circuit
These signals are important for monitoring safety devices installed on or around the elevator car.
3. Machine-Room Safety Circuit
The machine-room safety circuit includes several important safety devices:
U1.4–U1.3: Manual turning / emergency operation circuit
U1.2–U1.1: Overspeed governor circuit
U1.1–Y2.19: Control cabinet emergency stop circuit
An interruption in these circuits may prevent the elevator from entering normal operation.
4. Landing Door Lock Circuit
The landing door lock circuit varies according to the number of elevator stops.
X11.1–X11.2: Used for elevators with up to 16 floors/stops
X13.1–X13.2: Used for elevators with 16 to 32 floors/stops
The door lock circuit verifies that the landing doors are properly locked before the elevator is allowed to run.
5. Car Door Lock Circuit
The car door lock circuit is represented by:
Y2.19–Y3.20
The controller uses the door lock signal to confirm that the car door is safely closed before operation.
6. Deceleration Switch Circuit
The deceleration switches provide important position and speed-control signals during terminal approach.
Upward Deceleration
XL6–XL5: First-stage deceleration
XL8–XL7: Second-stage deceleration
XL10–XL9: Third-stage deceleration
Downward Deceleration
XL16–XL15: First-stage deceleration
XL18–XL17: Second-stage deceleration
XL20–XL19: Third-stage deceleration
These signals work together with the elevator control system to manage speed as the car approaches the terminal floors.
HITACHI Elevator Car-Top Electrical Connections
The car-top electrical box contains connections for several safety and auxiliary functions.
Common connections include:
|
Connection |
Function |
| 42.14–42.13 | Safety gear |
| 42.16–42.15 | Emergency exit |
| 42.1–42.2 | Left safety edge |
| 42.4–42.3 | Right safety edge |
| 41.25–42.9 | Car-top gong / floor announcement |
| 42.12–41.26 | Car-bottom gong / floor announcement |
| 42.17–42.18 | Emergency lighting |
| 42.23–42.24 | Car-top lighting box, 220V |
| 42.25–42.26 | 30V circuit |
| 41.29 | Ground |
| 42.19–42.20 | Car lighting |
| 42.20–42.21 | Car ventilation fan |
Pit Electrical Box Connections
The pit electrical box provides connections for several safety and auxiliary circuits:
XR1.7–XR1.8: Fire service switch
XR1.G: Ground
XR1.5–XR1.6: AC36V lighting and socket
XR1.3–XR1.4: AC220V socket
These circuits should be checked carefully when electrical equipment in the pit does not operate normally.
Common HITACHI Elevator Fault Codes
HITACHI elevator fault codes cover a wide range of control, safety, door, speed, communication, and positioning problems.
|
Code |
Fault Description |
| E10 | Main microcomputer board fault |
| E11 | Sub microcomputer board fault |
| E12 | Running contactor fault |
| E14 | Safety relay short-circuit fault |
| E15 | Safety circuit open fault |
| E16 | Software WDT operation |
| E17 | Door locked after three consecutive opening attempts |
| E20 | Brake short-circuit fault |
| E21 | Brake disconnection fault |
| E23 | 40D relay disconnection fault |
| E25 | 40G relay disconnection fault |
| E26 | Program/parameter fault |
| E27 | Repeated fault |
| E30 | Rotary encoder fault |
| E32 | Idle-running protection |
| E34 | Landing door lock short-circuit fault |
| E35 | Car door lock short-circuit fault |
| E37 | Reverse running fault |
| E38 | Running contactor disconnection fault |
| E41 | Low-speed overspeed fault |
| E42 | 50B relay disconnection fault |
| E50 | High-speed overspeed fault |
| E51 | Abnormal starting speed |
| E54 | Micro-leveling reverse overtravel |
| E55 | Forced deceleration switch fault |
| E56 | Micro-leveling overspeed |
| E57 | Micro-leveling overtravel |
| E58 | Low-speed fault |
| E60 | Floor-height measurement error |
| E61 | DC48V power interruption during operation |
| E62 | Floor-position error |
| E64 | Terminal deceleration curve abnormality |
| E70 | Inverter pre-alarm |
| E71 | Variable-frequency door operator fault |
| E73 | Door-zone operation fault |
| E75 | SCLB board communication fault |
| E77 | Excessive rescue operation |
| E78 | SLU board communication fault |
| E80 | Landing door lock opened during operation |
| E81 | Abnormal inspection status |
| E82 | Micro-leveling timeout |
| E85 | Micro-leveling sensor fault |
| E86 | Door-opening timeout |
| E87 | Door-closing timeout |
| E88 | Car door lock opened during operation |
| E89 | Inverter microcomputer set to keyboard control mode |
| E90 | Group control / parallel communication fault |
| E91 | Momentary power interruption detected |
| E92 | Power-failure self-running operation |
| E93 | Elevator rescue operation |
| E94 | Load-weighing sensor fault |
| 118 | 10T auxiliary contact fault |
Fault Codes and Safety Circuit Diagnosis
Some HITACHI fault codes can provide a useful starting point for identifying an interrupted safety signal.
For example:
E15 — Safety Circuit Open Fault
This fault indicates that the elevator safety circuit has been interrupted. Inspection should focus on the relevant safety switches, emergency stop circuits, wiring, and safety relays.
E34 / E35 — Door Lock Faults
E34 relates to the landing door lock circuit, while E35 relates to the car door lock circuit. Door lock contacts, wiring, and mechanical door-lock conditions should be checked.
E55 — Forced Deceleration Switch Fault
This fault is associated with the forced deceleration switch circuit. The corresponding switches and their wiring should be inspected for incorrect operation or signal interruption.
E62 — Floor Position Error
An E62 fault indicates that the elevator’s detected floor position does not match the expected position information. Position sensors, encoder feedback, leveling signals, and related wiring may require inspection.
E80 / E88 — Door Lock Opens During Operation
These faults indicate that the controller detected an abnormal door-lock signal while the elevator was running. The corresponding door lock circuit should be checked carefully before returning the elevator to service.
Why the Safety Circuit Matters
The elevator safety circuit is not simply a collection of individual switches. It is a coordinated protection system connecting different parts of the elevator.
A fault in any critical section may affect normal operation, including:
Safety circuit
Door lock circuit
Brake system
Terminal limit switches
Deceleration switches
Encoder feedback
Communication system
Emergency stop devices
Understanding the circuit structure makes it easier to connect a displayed fault code with the physical component that needs to be inspected.
Conclusion
The HITACHI elevator safety circuit integrates multiple safety devices throughout the hoistway, car, machine room, landing doors, and car doors. Together with the controller’s diagnostic system, these circuits provide continuous monitoring during elevator operation.
For maintenance engineers, understanding both the safety circuit structure and fault code meanings can provide a more effective starting point for troubleshooting and help reduce unnecessary component replacement and downtime.
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Post time: Aug-20-2026