FX Series Programmable Controlers Applied Instructions 5
5-75
5.7.9 ROTC (FNC 68)
Operation:
The ROTC instruction is used to aid the trackin
and positional movement of the rotar
table as it
moves to a specified destination.
Points to note:
a) This instruction has man
automaticall
de-
fined devices. These are listed on the ri
ht of
this pa
e.
b) The ROTC instruction ma
onl
be used
ONCE
.
c) The ROTC instruction uses a built in 2-phase
counter to detect both movement direction
and distance travelled. Devices D+0and D+1
are used to input the phase pulses, while
device D+2is used to input the ‘zero position’
on the rotar
table. These devices should be
pro
rammed as shown in the example below
(where the ph
sical termination takes place
at the associated X inputs).
The movement direction is found b
checkin
the relationship of the two phases of the 2
phase counter, e.
.
Mnemonic Function
Operands
Program steps
S
m
1
m
2
D
ROTC
FNC 68
(Rotar
table
control)
Controls a rotar
tables movement
is response to a
requested
destination/
position
D
Note:
uses 3
consecu-
tive
devices
S+1
≤
m1
K, H
Note:
m1= 2 to
32,767
K, H
Note:
m2= 0 to
32,767
Y, M, S
Note:
uses 8
consecu-
tive
devices
ROTC:
9 steps
m1
≥
m2
X10
K10D200 K 2
[ S ] [ m1 ] [ D ]
M 0
ROTC
[ m2 ]
Indirect user selected devices:
D
A-phase counter signal - input
D
B-phase counter signal - input
D
Zero point detection - input
D
High speed forward - output
D
Low speed forward - output
D
D
Low speed reverse - output
D
High speed reverse - output
m
1
Number of encoder pulses per
m
2
Distance to be travelled at low
speed (in encoder pulses)
S
Current position at the ‘zero point’
S
Destination position (selected
station to be moved to) relative to
the ‘zero point’ - User defined
S
Start position (selected station to
be moved) relative to the ‘zero
X1
X2
X0
M 0
M 1
M 2
A-phase
B-phase
A-phase
B-phase
A
phase leads
B
phase
B
phase leads
A
phase
