Rockwell Automation 8720MC High Performance Drives Installation Manual - Manual (Page 59)

Publication 8720MC-IN001D-EN-P — December 2002
8720MC Connector Data 2-25
The following table provides a description of the AM, BM, and IM
inputs for TTL encoders.
The following table provides a description of the AM and BM inputs
for Sine/Cosine encoders.
Parameter Description Minimum Maximum
AM, BM, and IM
ON State
Input Voltage Input voltage difference between the + input
and the - input that is detected as an ON
state.
+1.0V +7.0V
AM, BM, and IM
OFF State
Input Voltage Input voltage difference between the + input
and the - input that is detected as an OFF
state.
-1.0V -7.0V
Common Mode
Input Voltage Potential difference between any encoder
signal and logic ground.
-7.0V +12.0V
DC Current Draw Current draw into the + or - input. -30 mA 30 mA
AM, BM Input
Signal Frequency
Frequency of the AM or BM signal inputs.
The count frequency is 4 times this
frequency, since the circuitry counts all four
transitions.
— 1 MHz
IM Pulse Width
Pulse width of the index input signal. Since
the index is active for a percentage of a
revolution, the speed will determine the
pulse width.
125 nS —
AM / BM
Phase Error,
2.5 MHz Line
Frequency
Amount that the phase relationship between
the AM and BM inputs can deviate from the
nominal 90°.
-22.5° +22.5°
AM / BM
Phase Error,
1 MHz Line
Frequency
Amount that the phase relationship between
the AM and BM inputs can deviate from the
nominal 90°.
-45° +45°
Parameter Description Minimum Maximum
AM and BM
Input Signal
Frequency
Frequency of the AM or BM signal inputs. — 250 kHz
AM and BM
Input Voltage Peak-to-peak input voltages of the AM and BM
inputs
0.5V (p-p) 2.0V (p-p)