Manual

82 Rockwell Automation Publication 1407-UM001G-EN-P - April 2013
Chapter 4 CGCM Unit Configuration
Volts/Hz Tab
The Volts/Hz tab is used to configure the unit’s settings related to operation of
the Volts/Hz compensation function. The parameters define a curve, which
determines the Volts/Hz response.
• Volts per Hertz Upper Knee Frequency - Establishes the frequency at
which the V/Hz characteristic starts to reduce the generator voltage as a
function of generator frequency. Tag Vp e rHz _ H iK n e eFr e q in the
configuration table stores this value, expressed in Hertz. The upper knee
frequency must be greater than the lower knee frequency.
• Volts per Hertz Upper Slope - Establishes the rate at which the V/Hz
characteristic reduces the generator voltage as a function of generator
frequency between the upper and lower knee frequencies. Tag
Vp e r H z _ H i S l o p e in the configuration table stores this value, expressed as
a number that reflects per unit change in voltage for each per unit change
in frequency.
• Volts per Hertz Lower Knee Frequency - Establishes the frequency at
which the V/Hz characteristic starts to reduce the generator voltage at the
lower slope rate as a function of generator frequency. Tag
Vp e r H z _ L oK ne e Fr e q in the configuration table stores this value,
expressed in Hertz. The lower knee frequency must be less than the upper
knee frequency.