Engaging the ERMS Function

@writer: this topic is present in user guides: MTZ1 (DOCA0100EN) + MTZ2/3 (DOCA0101EN)

Presentation

Engage the ERMS function to reduce protection settings so that the circuit breaker trips as soon as possible when an internal arc fault occurs. Minimizing the time between fault and trip helps to reduce the risk of injury when qualified electrical personnel are near energized equipment.

Conditions for Engaging the ERMS Function

The ERMS function is available when the Energy Reduction Maintenance Settings Digital Module is purchased and installed on the MicroLogic X control unit.

Operating Principle

The ERMS function can be engaged as follows:

With the EcoStruxure Power Device app (password-protected).

There is a digital lock between a smartphone running the EcoStruxure Power Device app and the MicroLogic X control unit.
By using an external selector switch connected to the optional ESM ERMS switch module.

The ESM module is installed in the circuit breaker and is connected to an external selector switch, which can be padlocked. The ERMS function is engaged by turning the external selector switch.

The ERMS function can be engaged with both the EcoStruxure Power Device app (password-protected) and an external selector switch.

The ERMS function must be disengaged by the interface that engaged it:

If it is engaged on a smartphone, it must be disengaged by the same smartphone.
If it is engaged by the external ERMS switch connected to the ESM module, it must be disengaged by the ERMS switch.
If it is engaged by both smartphone and ERMS switch, it must be disengaged by both smartphone and ERMS switch.

While the ERMS function is engaged:

A blue ERMS LED (A) is lit on the front face of the MicroLogic X control unit
Quick View scrolling is interrupted and the ERMS engaged message is displayed with a blue backlight
All screens, except pop-up messages, are displayed with a blue backlight

For more information, refer to DOCA0102•• MasterPacT MTZ - MicroLogic X Control Unit - User Guide in Related Documents at the beginning of this guide.

Engaging the ERMS Function

NOTICE
HAZARD OF LOSS OF POWER Ensure that the ERMS protection settings are properly configured prior to engagement. Failure to follow these instructions can result in loss of service due to power loss.

The ERMS can be engaged in different ways, according to the circuit breaker configuration and its accessories:

Type	Accessories	Action
Through EcoStruxure Power Device app	–	Send a command from the EcoStruxure Power Device app to engage the ERMS function, through Bluetooth Low Energy wireless communication or USB OTG connection. The action is password-protected.
Through an external selector switch connected to the ESM module	ESM ERMS switch module External selector switch	Turn the external selector switch to the Engaged position

Disengaging the ERMS Function

DANGER
HAZARD OF ELECTRIC SHOCK, EXPLOSION, OR ARC FLASH Prior to disengaging ERMS: Carefully inspect your work area, and remove any tools and objects left inside the equipment. Ensure that all personnel are away from the equipment, and devices, doors, and covers are in place. Failure to follow these instructions will result in death or serious injury.

A digital lock function establishes a digital lock between a smartphone running the EcoStruxure Power Device app and the MicroLogic X control unit when ERMS is engaged by the smartphone. The digital lock function ensures that when the ERMS function is engaged by a smartphone, it must be disengaged by the same smartphone.

The way to disengage the ERMS function depends on how it was engaged:

Type	Accessories	Action
Through EcoStruxure Power Device app	–	Disengage the ERMS function on the same smartphone that engaged it
Through an external selector switch	ESM ERMS switch module External selector switch	Turn the external selector switch to the Disengaged position
Through EcoStruxure Power Device app and an external selector switch	ESM ERMS switch module External selector switch	Disengage the ERMS function on the same smartphone that engaged it Turn the external selector switch to the Disengaged position