Rockwell Automation 8720MC High Performance Drives Installation Manual - Manual (Page 53)

Publication 8720MC-IN001D-EN-P — December 2002
8720MC Connector Data 2-19
Analog Inputs
The analog input to the drive can provide a velocity command signal.
A 14 bit A/D converter digitizes the signal. The configuration of the
input is shown in Figure 2.16.
Figure 2.16
Analog Input Configuration
The following table provides a description of the analog input
specifications.
10k Ω 10k Ω
20k Ω
20k Ω
1000 pF
1000 pF 0.01 µF
COMMAND +
COMMAND -
0.01 µF
10k Ω 10k Ω
Parameter Description Minimum Maximum
Resolution
Number of states that the input signal is divided into
which is 2
(to the number of bits)
.
14 bits —
Input
Impedance Open circuit impedance measured between the + and
- inputs.
20 k
Ω
—
Input Signal
Range
Voltage applied to the input -10V +10V
Offset Error
Deviation from the correct value expected from
analog-to-digital conversion when 0V is applied to the
input.
— 50 mV
Gain Error
Deviation of the transfer function from unity gain,
expressed in a percent of full scale.
— 1%
Update Rate Update rate of the firmware-accessible registers. — 125
µS