3.8
Special Wiring
151
3.8.5 Using an Absolute Encoder
1)
Outline
An absolute value detection system detects an absolute position of the machine even
when the servo system is OFF. If such a system is to be formed in the host controller, use
an SGM or SGMP Servomotor with absolute encoder. Consequently, automatic opera-
tion can be performed without zero return operation immediately after the power is turned
ON.
SGM
jjj
W1
j
(SGMP
jjj
W1
j
)
Always detects
absolute position
Zero return
operation
12-bit absolute encoder
2)
Standard Connection Diagram for a 12-bit Absolute Encoder Mounted on a Servo-
motor
•
Interface Circuit
Host controller
Battery
Line receiver
Serial
interface
circuit
Clear
Up/
down
counter
De-
coder
Servopack
Servomotor
12-bit absolute encoder
Represents twisted pair
wires
Serial
interface
circuit
SG
BAT+
BAT-
FG
1CN-50
1CN-1
1CN-49
1CN-48
1CN-20
1CN-19
1CN-36
1CN-35
1CN-34
1CN-33
1CN-22
1CN-21
1CN-2
1CN-4
Line Receiver Used:
SN75175 or MC3486 manufactured by Texas Instruments Inc.
Termination Resistor R: 220 to 470
Ω
Normally, PAO serial data is used. In this case, PS serial interface is unnecessary.
3