Mitsubishi Elevator Light Curtain Box S100-C-LPS 100/102 BD860 BD660

S100-C-LPS 100/102 is a light curtain control box commonly used in Mitsubishi elevator door protection systems.

This unit typically works together with S100 series light curtains and door safety sensors to support obstacle detection during elevator door operation.

It is commonly associated with:

• Mitsubishi light curtain systems
• elevator door protection circuits
• door reopening functions
• passenger safety detection
• BD860 / BD660 door sensor assemblies

The S100 series is widely used in Mitsubishi elevator door safety applications and is often supplied together with matching light curtain components.

Compatible light curtain box and system references include: 

• S100-C-LPS
• S100
• S100-C
• S100-102
• BD860
• BD660

Please confirm whether the original installation uses the matching S100 system before ordering.

A Door Reopening Problem Found During Maintenance

During maintenance work in a hotel project in the Middle East, technicians received reports that the elevator doors repeatedly reopened even when no passenger was passing through the entrance.

At first, the door controller was suspected.

However, after inspection, the issue was traced to unstable signals within the door protection circuit.

The light curtain itself remained functional, but the control box was not processing the detection signals consistently, causing unnecessary door reopening behavior.

After replacement and signal testing, door operation returned to normal.

Why Door Protection Components Are Often Checked Together

When troubleshooting door safety systems, technicians usually inspect:

• light curtain transmitters
• receiver bars
• control boxes
• door controller inputs
• cable connections

In many Mitsubishi installations, a fault in one part of the protection circuit may create symptoms that appear to originate from another component.

For this reason, maintenance teams rarely replace only the sensor without checking the related signal processing units.

A Common Issue in Older Installations

After years of continuous operation, door protection systems may gradually experience:

• unstable detection signals
• intermittent door reopening
• communication interruptions
• connector oxidation
• power supply fluctuations

These symptoms do not always indicate a failed light curtain.

In some cases, the control box becomes the actual source of the problem.

Maintenance Reminder

Before replacement:

• verify S100-C-LPS model compatibility
• confirm matching light curtain configuration
• inspect signal wiring
• check power supply stability
• test door reopening response after installation

Some Mitsubishi elevator generations use different light curtain control architectures even when the sensor appearance is similar.

Many maintenance teams inspect the entire door protection circuit when replacing S100-C-LPS units because signal stability often depends on multiple interconnected components.