10 years of UCM/A3 MOD-Kit by SLC: The latest generation

The UCM/A3 MOD-Kit is the ideal safety circuit for retrofitting the UCM/A3 function to existing systems with older controllers. It not only meets the requirements of EN81-20:5.6.7 to prevent unintended car movements but also provides significant benefits for service personnel and enables a sustainable, resource-efficient use of emergency batteries. The major advantage of the system is that the fault signal from the monitoring electronics is directly integrated into the safety circuit of the elevator control. This eliminates the need for further adjustments to the hardware and software of the existing old controller.

The essential functions of the UCM/A3 MOD-Kit are:

Detection of unintended car movements through redundant magnetic sensors in the door zones
Emergency stop of the car and shutdown of the drive system upon detection of an unintended car movement.
Car release in emergency situations through the start/stop option, which can be activated by pressing a button even during a power outage.
Quick testing of the A3 brake components during commissioning and for condition monitoring using a separate button.

Advantages of the UCM/A3 MOD-Kit::

Compatible with any controller without modifications to hardware and software
Innovative battery management with state indication (LED)
Voltage monitoring of emergency power supply with display
Travel direction detection for releasing the safety device
Emergency evacuation button

special features of the SLC UCM print module

Scope of delivery:

Safety control system in a dedicated control cabinet, including a safety module, SLC UCM print module, emergency power device, power supply, 2 lead-acid batteries, and cables for elevator control
Shaft suspension cable
2 guy clamps for the suspension cable
2 magnetic sensors
Magnetic strips for the door zones
Magnetic strips for the door zones


Shaft or car installation.

The magnetic tapes are to be installed in the door zone area on the rail at the same height. The two redundant magnetic sensors are to be mounted on the car at different heights. For standard door zones, the magnet strips of standard length should be used. For extended door zones (“door open while entering”), magnet strips with double length should be used.


Features of the integrated control logic of the SLC UCM print module

Battery status monitoring, battery charging process control, deep discharge protection
Switching between battery charging and power supply
Emergency release with start/stop option through button activation (start: 6 seconds / stop: 8 seconds)
The number of emergency release actions is only limited by the battery capacity
To continue ongoing evacuation actions, the deep discharge protection of the battery can be deactivated
Automatic shutdown of the emergency release option after 60 minutes to preserve battery life
Safe shutdown of UCM/A3 brake components (6 seconds if the car is in the door zone, otherwise 30 seconds)
Control of the power supply voltage of UCM/A3 brake components (e.g., governor overspeed brake magnet) to increase the lifespan and reliability of the UCM/A3 system and reduce energy consumption. The drive and holding voltage of the brake magnet varies between 12V and 24V (overexcitation)

Monitoring functions of the UCM/A3 MOD kit

Monitoring and display of mains voltage and voltage of the 24vDC power supply unit to ensure UPS function
Monitoring of the hardware board and more connected components (power supply, batteries, A3 brake component, safety switch) using galvanically isolated, freely configurable changeover contacts
Signaling of an emergency rescue action by flashing LED
Display of the direction of travel for targeted release of the catch brake during evacuation
Display of the status of the A3 release unit (e.g. solenoid attracted / released)

Evacuation procedure with the UCM/A3 MOD kit