External brake resistor, monitoring when connected to ECS supply module
Question:
How are the brake resistors at the ECS supply module monitored?
Answer:
The monitoring of internal and external brake resistors is different.
Internalbrake resistor
The load of the internal brake resistor is simulated in the software and monitored.
For this, duty time and DC bus voltage are multiplied and smoothed via the PT1 filter. When a defined limit is exceeded, the device switches off with OC6 (overload internal brake resistor). This monitoring is suitable exclusively for the internal brake resistor.
Externalbrake resistor
An external brake resistor is monitored by its thermal sensor.
The connection of this sensor to terminals T1 and T2 of the supply module is mandatory. The supply module cannot recognize whether an external resistor is connected; therefore the OC6 monitoring routine for the internal brake resistor continues.
The OC6 monitoring must be switched off (mandatory) when an external resistor is connected (set C0579 to -3-) to avoid tripping.
