3 Basic Instructions Explanations: 1. DCNT is the instruction for enabling the 32-bit high-speed counters C200 ~ C255. 2. For general purpose addition/subtraction counters C200 ~ C234, when DCNT goes from Off to On, the present value in the counter will pulse 1 (counting up) or minus 1 (counting down) according to the modes set in special M1200 ~ M1235. 3. For high-speed addition/subtraction counters C235 ~ C255, when the high-speed counting pulse input goes from Off to On, the counting will start its execution. For the input terminals (X0 ~ X17) and counting methods (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 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:
DVP-PLC Application Manual 3-11 Mnemonic Function Program steps Controllers ES EX SS SA SX SC EH2 SV EH3 SV2 DCNT 32-bit counter 1 C-K C200 ~ C255, K-2,147,483,648 ~ K2,147,483,647 Operand C-D C200 ~ C255, D0 ~ D9999 ES E X S S SA SX SC EH 2 SV EH 3 SV DCNT C254 K1000 DCNT C254 K1000 Set value of counter C254 as K1,000 Mnemonic Function Program steps Controllers ES EX SS SA SX SC EH2 SV EH3 SV2 MC / MCR Master control Start/Reset 1 N0 ~ N7 Operand Controllers ES EX SS SA SX SC E H2 SV E H3 S V2 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