FX Series Programmable Controlers Applied Instructions 5
5-76
d) When the ‘zero point’ input (D+2) is received the contents of device S+0is reset to ‘0’ (zero).
Before startin
an
new operation it is advisable to ensure the rotar
table is initialized b
movin
the ‘zero point’ drive do
or marker around to the ‘zero point’ sensor. This could be
considered as a calibration technique. The re-calibration of the rotar
table should be
carried out periodicall
to ensure a consistent/accurate operation.
e) Devices D+3 to D+7 are automaticall
set b
the ROTC instruction durin
its operation.
These are used as fla
s to indicate the operation which should be carried out next.
f) All positions are entered in the form of the required encoder pulses. This can be seen in the
followin
example:
- Example:
A rotar
table has an encoder which outputs 400 (m1) pulses per revolution. There are 8
stations (0 to 7) on the rotar
table. This means that when the rotar
table moves from one
station to its immediatel
followin
station, 50 encoder pulses are counted. The ‘zero
position’ is station ‘0’ (zero). To move the item located at station 7 to station 3 the followin
values must be written to the ROTC
instruction:
S+1=3
×
50 = 150 (station 3’s position in encoder pulses from the zero point)
S+2=7
×
50 = 350 (station 7’s position in encoder pulses from the zero point)
m1= 400 (total number of encoder pulses per rev)
The rotar
table is required approach the destination station at a slow speed startin
from
1.5 stations before the destination. Therefor;
m2= 1.5
×
50 = 75 slow speed distance either side of the destination station (in
encoder
pulses)
