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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
g
and positional movement of the rotar
y
table as it
moves to a specified destination.
Points to note:
a) This instruction has man
y
automaticall
y
de-
fined devices. These are listed on the ri
g
ht of
this pa
g
e.
b) The ROTC instruction ma
y
onl
y
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
y
table. These devices should be
pro
g
rammed as shown in the example below
(where the ph
y
sical termination takes place
at the associated X inputs).
The movement direction is found b
y
checkin
g
the relationship of the two phases of the 2
phase counter, e.
g
.
Mnemonic Function
Operands
Program steps
S
m
1
m
2
D
ROTC
FNC 68
(Rotar
y
table
control)
Controls a rotar
y
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 ]
Assigned devices
Indirect user selected devices:
D
+0
A-phase counter signal - input
D
+1
B-phase counter signal - input
D
+2
Zero point detection - input
D
+3
High speed forward - output
D
+4
Low speed forward - output
D
+5
Stop - output
D
+6
Low speed reverse - output
D
+7
High speed reverse - output
Rotary table constants:
m
1
Number of encoder pulses per
table revolution
m
2
Distance to be travelled at low
speed (in encoder pulses)
Operation variables:
S
+0
Current position at the ‘zero point’
READ ONLY
S
+1
Destination position (selected
station to be moved to) relative to
the ‘zero point’ - User defined
S
+2
Start position (selected station to
be moved) relative to the ‘zero
point’ -User defined
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