11
D4 (RUN)
The D4 (RUN) input, when received,
causes the system to run the currently
active profile (that is, the profile selected
by the Run mode).
The Run input and the Jog inputs (D14
and D12, described earlier in this
chapter) are mutually exclusive; that is,
the Run input is valid only when the Jog
input is ’Off’ (low), and vice versa. If
both the Run and the Jog inputs go ‘On’
– an illegal state – the SMC20 ignores
both.
D2 (I)
The D2 (I) input causes the system to
run its home sequence.
Position Feedback Sensor
Connection
Figure 2-16. Position Feedback
Sensor Connections
Incremental Encoder
Connections
The SMC20 interfaces with
industry-standard incremental encoders.
The encoder output, which is a square
wave, consists of “A” and “B” channels
in quadrature, with a “C” marker pulse
channel. The SMC20 accepts as input,
differential line receivers that conform to
RS485; however, it will also accept
single-ended signals.
The position feedback encoder
connection also includes jumper-
sele5 VDC or +15 VDC to power
the encoder. See Appendix B for jumper
settings.
Figure 2-16 locates the position
feedback encoder connections on the
SMC20 front panel. Figure 2-17 shows
the pin layout in each encoder
connection, and Table 2-4 presents the
name and description for each pin in the
connection. The encoder connection
mates with a DB-9 female connector.
Figure 2-17. Feedback Pin Layout, Pin
Layout, Cable End
Pin
No.
Name
Description/
Function
1
V+
P ositive
voltage
supply
for
encoder.
Selectable
by
jumper
for
+5
VDC
or
+15
VDC
(See
Appendix
B).
2
GND
Common
for
supply.
Can
be
jumper
selected
to
provide
-15
VDC
(See
Appendix
B).
3
“A” HI
Differential
A "
channel
input
RS485
4
“A” LO
input.
RS485
compatible.
5
“B” HI
Differential
B"
channel
input.
RS485
compatible.
6
“B” LO
Differential
B"
channel
input.
RS485
compatible.
7
“C” HI
Differential
C"
channel
input
RS485
8
“C” LO
input.
RS485
compatible.
9
GND
P ower
supply
common.
Table 2-4. Position Feedback Encoder
Connections
As already mentioned, the SMC20
encoder connections will accept
single–ended inputs. Figure 2-18 shows
the recommended single–ended
connections.
Figure 2-18. Recommended Single-
Ended Connections
