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TTL Incremental SubD - Encoder Connections
1. Maximum Encoder voltage: +5.2 V
2. Encoder line number: 1...16383 ppr
2500 ppr is recommended and gives best speed resolution and regulation
performance for applications with a maximum motor speed of up to 4500
rpm.
F5 Interface cutoff frequency: 300 kHz
Observe cutoff frequency of the encoder:
g • n
max
f
limit
> —————
60
g = Encoder increments (ppr)
n = Encoder speed (rpm)
f = Encoder operating frequency (Hz)
3. Signal specications:
Four signals consist of two square-wave
pulses that are electrically 90° out of phase
and their inverse signals (TTL-push-pull
signals / RS422-conformity). The Minimum
"on" voltage level is 2.0V and the maximum
"off" voltage level is 0.5V. The encoder must
be electrically isolated from the motor shaft.
Otherwise, noise from the motor may corrupt
the encoder signals.
4. Cable specications:
The encoder cable shall not be too long such that the voltage drop of supply
voltage on the encoder cable results in a voltage less than the minimum
encoder supply voltage. Typically, encoder lines should not be longer than
160 ft (50 m). The following must be valid for trouble-free operation.
[ (I
Encoder
• R
Line
) + V
Encoder (min)
] < +5.2 V
R
Line
is the sum of the resistance of the supply wires both +V and com.
For maximum noise immunity, the encoder cable shall consist of individually
shielded twisted pairs with one overall shield. The individual shields should
be connected to 0V (com) pin 13 on the Sub D connector and be kept
separate from the outer shield. The outer shield should be connected to
earth ground, the housing of the Sub D connector.
The cable shall be kept a minimum of 8 inches (20 cm) away from all
wires having greater than 24VDC on them. For best results, run the
encoder cable in a separate conduit from the controller to the motor.
2...5 V
0 V
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