Rockwell Automation 1397 Pulse Encoder Interface Installation Inst. - Manual (Page 2)

1397 Pulse Encoder Interface Card 2
1397-5.13 June, 1997
Pulse Encoder Waveform: Square Wave — Constant Amplitude
Requirements Over Entire Speed Range, Including Zero
Speed
Differential Single-Channel or Quadrature
Output: (Dual-Channel)
Duty Cycle: 50% Nominal
Quadrature: Required for All Regenerative Drives
Line Drivers: May Be Required to Satisfy the Pulse
Encoder Interface Card’s Voltage Limits
Wiring Refer to the 1397 User Manual — Publication 1397-5.0
Requirements
Pulse Encoder Power Supply: +15VDC,
±
5%, 200mA Maximum
Interface Card
Requirements
Absolute: 100kHz
Max Frequency
Min Frequency: 0kHz
Recommended: 73kHz
Max Frequency
Differential Voltage:
Input +25VDC Maximum to Common
Requirements +5VDC Minimum Differential
+15VDC Maximum Differential
Input Impedance:
11k
Ω
Line Termination:
100
Ω
in Series with (1) 3900pf Capacitor
Specifications
How to Select the PPR of
a Pulse Encoder A 120 PPR pulse encoder can maintain a minimum speed of 25 RPM
at the accuracy listed in the
Specifications above. The drive can operate
below minimum motor speed but with degraded accuracy. If a lower
motor speed is required, a pulse encoder with a higher PPR rating is
required.
where:
PPR
1
= The Pulse Encoder’s Minimum
Pulses-per-Revolution
N
1
= The Required Minimum Motor Speed in RPM
PPR
1
= [1]
×
[60]
——————
N
1
×
0.02
Step 1 — Determine the pulse encoder’s minimum PPR requirement.
To select a pulse encoder —