Allen-Bradley PowerFlex 70 Reference Manual page 29

Terminal Designations & Wiring Examples
Refer to the appropriate PowerFlex User Manual or "Wiring and Grounding
Guidelines for Pulse Width Modulated (PWM) AC Drives, " publication
DRIVES-IN001 for I/O terminal designations and wiring examples.
How [Analog Inx Hi/Lo] & [Speed Ref A Hi/Lo] Scales the Frequency
Command Slope with [Minimum/Maximum Speed]
Example 1:
Consider the following setup:
• [Anlg In Config], bit 0 = "0" (voltage)
• [Speed Ref A Sel] = "Analog In 1"
• [Analog In1 Hi] = 10V
• [Analog In1 Lo] = 0V
• [Speed Ref A Hi] = 60 Hz
• [Speed Ref A Lo] = 0 Hz
• [Maximum Speed] = 45 Hz
• [Minimum Speed] = 15 Hz
This operation is similar to the 0-10 volts creating a 0-60 Hz signal until the
minimum and maximum speeds are added. [Minimum Speed] and [Maximum
Speed] limits will create a command frequency deadband.
[Minimum Speed]
[Analog In1 Hi]
10V
Frequency Deadband
0-2.5 Volts
[Analog In1 Lo]
0V
0 Hz
[Speed Ref A Lo]
Slope defined by (Analog Volts)/(Command Frequency)
This deadband, as it relates to the analog input, can be calculated as follows:
1. The ratio of analog input volts to frequency (Volts/Hz) needs to be
calculated. The voltage span on the analog input is 10 volts. The frequency
span is 60 Hz.
10 Volts/60 Hz = 0.16667 Volts/Hz
2. Determine the frequency span between the Minimum and Maximum Speed
limits and Speed Ref A Hi and Lo.
[Speed Ref A Hi] – [Maximum Speed] = 60 – 45 = 15 Hz and . . .
[Minimum Speed] – [Speed Ref A Lo] = 15 – 0 = 15 Hz.
Rockwell Automation Publication PFLEX-RM001H-EN-P - June 2013
Motor Operating Range
Command Frequency
15 Hz
Analog Inputs
[Maximum Speed]
Frequency Deadband
7.5-10 Volts
45 Hz 60 Hz
[Speed Ref A Hi]
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