What does the Power removal function do on a Lexium drive ?
The Power Removal safety function shuts off the motor torque safely. The Power Removal safety function integrated into the product can be used to implement the "Emergency Stop" control function (EN 60204-1) for Category 0 Stop and Category 1 Stop. In addition, this safety function prevents the drive from unexpected restart.
The power removal function on a Lexium 15 is via the terminal "PWR"
The power removal function on a Lexium 05 is via the terminals "PWRR_A" and "PWRR_B"
If there are no problems with the safe operation of the machine, then there should be 24V d.c. applied to these terminals to enable the drive to operate safely.
If a problem arises that threatens the safety of people and equipment, then the 24V d.c. should be removed. A redundant safety architecture inside the drive, which is permanently monitored by a diagnostic function, then stops all power supply to the motor, preventing any restarting
This power removal safety function complies with the following standards:
Safety of machinery EN 954-1 category 3
Functional safety IEC/EN 61508-1 SIL2
(will comply with) the future international standard on safety of machinery (IEC 62061)
It can therefore be integrated in a category 3 (EN 954-1) or SIL2 (IEC/EN 61508-1 SIL2) safety function as long as the connection diagram associated with the drive and the safety function is compliant; failure to adhere to the recommendations relating to its setup does not guarantee the SIL capability of the Power Removal function (mean probability per hour of undetected dangerous failure between 10-6 and 10-7)
Category 1 or SIL1
If the machine to be made safe has to conform to category 1 (EN 954-1) or SIL1 (IEC/EN 61508): the Power Removal input may not be used and may therefore be bridged. A contactor or a switch between the drive and the motor will have to be used.
Category 3 or SIL2
If the machine to be made safe has to conform to category 3 (EN 954-1) or SIL2 (IEC/EN 61508), you will have to use the Power Removal safety function of the drive in combination with Preventa safety modules which monitor the emergency stop circuits.
The most commonly used Preventa safety modules are type XPSAV or XPSATE.
Suggested Schemes for the Servo drives with the Preventa modules can be found in the catalogues for each drive.