6-20
Interfaces
Interface Cable Examples
The use of differential signals is highly recommended
. This is due to the immunity of differential signals
to common mode interference. Single-ended encoder interface circuits are not recommended, and may
result in system malfunction.
To improve noise immunity, a cable shield should terminate at both ends of the cable. Shields should
connect to the backshell of the connectors with termination around the full circumference (360°). The
connectors should attach to chassis ground (not signal common).
Intro
F
IGURE
6.25
External Encoder Interface via TTL Differential Line Drivers
Intro
F
IGURE
6.26
Complementary Encoder Interface via 7406 Line Drivers with Pull-up Resistors
Ch A
ENCODER
AX+
AX-
14
15
J1
Drive
twisted pair
Ch B
BX+
BX-
16
17
twisted pair
Ch I
IX+
IX-
18
19
twisted pair
Drive Chassis
Encoder Case
2
4
+5V
Supply
Return
+5 Volts
1
3
+5V
Supply
+5VDC
5V @ 250 mA
ECOM
twisted pair
For horizontal dashed lines,
connect only if J1 sources Encoder power
ENCODER
J1
Drive
Ch B
BX+
BX-
16
17
twisted pair
Drive Chassis
Encoder Case
+5 Volts
7406
Ch A
AX+
AX-
14
15
+5 Volts
7406
Ch I
IX+
IX-
18
19
+5 Volts
7406
twisted pair
twisted pair
twisted pair
2
4
+5V
Supply
Return
+5 Volts
1
3
+5V
Supply
+5VDC
5V @ 250 mA
ECOM
For horizontal dashed lines,
connect only if J1 sources Encoder power
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