Siemens CU240B-2 - Page 321

Advanced commissioning
6.7 Application-specific functions
Converter with the CU240B-2 and CU240E-2 Control Units
Operating Instructions, 01/2016, FW V4.7 SP6, A5E34259001B AC
321
Speed deviation monitoring
Using this function, the inverter calculates and monitors the speed or velocity of a machine
component. The inverter analyzes an encoder signal, calculates a speed from the signal,
compares it to the motor speed and reports any excessive deviation between the encoder
signal and the motor speed.
Examples of how the function can be used:
● Gearbox monitoring for traction drives and hoisting gear
● Drive belt monitoring for fans and conveyor belts
● Blocking protection for conveyor belts
You require a transmitter for this function, e.g. a proximity switch. The inverter analyzes an
encoder signal at max. 32 kHz.
The function is only available with the CU240E-2 Control Unit via digital input DI 3.
Image 6-59 Speed deviation monitoring
Principle of operation
The inverter determines the speed deviation from the calculated speed r0586 and the speed
list value r2169. p2181 determines the response of the inverter if the deviation is excessive.
Image 6-60 Time response of monitoring speed deviation