3 Basic Instructions
DVP-PLC Application Manual
3-10
(counting up/down) of the high-speed counter, see Chapter 2.7 Numbering and Function of Counter [C] for more
details.
4. When DCNT is Off, the counting will stop, but the existing present value in the counter will not be cleared. To
clear the present value and the contact, you have to use the instruction RST C2XX. Use externally designated
input points to clear the present values and contacts of high-speed addition/subtraction counters C235 ~ C255.
Program Example:
Ladder diagram: Instruction code: Operation:
LD M0 Loading in contact A of M0
M0
C254DCNT
K1000
DCNT C254 K1000 Set value of counter C254 as K1,000
Mnemonic Function Program steps
MC / MCR
Master control Start/Reset 1
Controllers
ES EX SS SA SX SC EH SV
Operand
N0 ~ N7
Explanations:
1. MC is the main-control start instruction. When MC instruction is executed, the execution of instructions between
MC and MCR will not be interrupted. When MC instruction is Off, the actions of the instructions between MC and
MCR are:
Instruction type Explanation
General purpose timer
Present value = 0
Coil is Off, No action for the contact
Accumulative timer Coil is Off, present value and contact stay intact
Subroutine timer
Present value = 0
Coil is Off, No action for the contact
Counter Coil is Off, present value and contact stay intact
Coils driven by OUT
instruction
All Off
Devices driven by SET and
RST instructions
Stay intact
Application instructions
All disabled.
The FOR-NEXT nested loop will still execute back and forth for N times.
Instructions between FOR-NEXT will act as the instructions between MC
and MCR.
2. MCR is the main-control end instruction that is placed in the end of the main-control program. There should not
be any contact instructions prior to MCR instruction.
3. MC-MCR main-control program instructions support the nested program structure (max. 8 layers) and please
use the instruction in the order N0 ~ N7.
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