Advanced commissioning
7.7 Application-specific functions
Unit changeover
Description
Using the unit switchover function, you can switch over parameters and process variables for
input and output to an appropriate system of units: US units, SI units or relative variables as
a %.
Independent of this, you can define the units for process variables or change over to
percentage values.
Specifically, you have the following options:
● Changing over the motor standard (Page 177) IEC/NEMA
● Changing over the unit system (Page 178)
● Changing over process variables for the technology controller (Page 178)
The motor standard, the unit system as well as the process variables can only be changed
offline.
Restrictions for the unit changeover function
● The values on the rating plate of the inverter or motor cannot be displayed as percentage
values.
● Using the unit changeover function several times (for example, percent → physical unit 1
→ physical unit 2 → percent) may lead to the original value being changed by one decimal
place as a result of rounding errors.
● If the unit is changed over into percent and the reference value is then changed, the
percentage values relate to the new reference value.
Example:
– For a reference speed of 1500 rpm, a fixed speed of 80% corresponds to a speed of
1200 rpm.
– If the reference speed is changed to 3000 rpm, then the value of 80% is kept and now
means 2400 rpm.
Reference variables for unit changeover
p2000 Reference frequency/speed
p2001 Reference voltage
p2002 Reference current
p2003 Reference torque
r2004 Reference power
p2005 Reference angle
p2006 Reference temperature
Converter with control units CU240D-2
176 Operating Instructions, 04/2015, FW V4.7.3, A5E34262100B AB
To Next Page
Loading...
