72
SC100/200 Series Function Block Application Manual EM-6460-C
5.2.3 RAMP PROGRAM WITH EXTENDED TIME SPAN
Single batch program continuing for several tens of days can be realized by use of hold switches to halt and resume the
program periodically. Parameters used in the program must be multiplied by appropriate conversion factors defined by the
degree of time span expansion (clock pulse rate).
■
CLOCK PULSE RATE V.S. CONVERSION FACTOR
CLOCK PULSE RATE
HOLD TIME (T) CONVERSION FACTOR
RAMP RATE (K) CONVERSION FACTOR
ON for 1 second / OFF for 9 seconds
ON for 1 second / OFF for 99 seconds
Tn x 10
Tn x 100
Kn x 0.1
Kn x 0.01
■
BLOCK DIAGRAM
■
OPERATION
Clock cycle of Timer block is not synchronized with the Controller’s computation cycle. Counter block is used instead of Timer
to count pulses generated by System’s Internal Switch block (Switch S5, G80) which repeats ON-OFF cycles every second.
The internal switch is described in Sequential Control block.
The following explanations do not include the sequence to start/reset the ramp program.
hold
to PID block SP
SEQ
G81
ISW
Internal SW
G80
PRG
G72
CTR
Ramp Program
Sequence
Counter
G30
STEP 01
INTERNAL SW
ON
STEP 02
COUNTER
COUNT OFF TIME
Program hold SW turned ON
(program halted)
Program hold SW turned OFF
Counter operation complete
ON
Internal SW turned OFF
