2 Functions of Devices in DVP-PLC Function Group Single Step Execution Number M1170, M1171, D1170 Contents: 1. Special D and special M for single step execution for EH2/SV/EH3/SV2: 2. The function: a) Execution timing: The flag is valid only when PLC is in RUN status. b) Action steps: i) When M1170 is enabled, PLC enters the single step execution mode. PLC stays at a specific instruction, stores the location of STEP in D1170 and executes the instruction once. ii) When M1171 is forced “On”, PLC executes the next instruction and stops. At the same time, PLC auto-force “O ff” M1171 and stops at the next instruction. D1170 stores the present STEP value.
iii) When Y output is in single step execution mode, Y outputs immediately without having to wait until END instruction is being executed. 3. Note: a) Instruction that will be affected by scan time will be executed incorrectly due to the single step execution. For example, when HKY instruction is executed, it takes 8 scan times to obtain a valid input value from a key. Therefore, the single step execution will result in incorrect actions. b) High-speed pulse input/output and high-speed counter comparison instructions are executed by hardware; therefore, they will not be affected by the single step execution. Function Group 2-phase Pulse Output Number M1172 ~ M1174, D1172 ~ D1177 Contents: 1.
Special D and special M for two-phase pulse output for SA/SX/SC: (The special data registers and the special auxiliary relays are not applicable to SX V3.0 and above because the function is replaced by PLSY. Users can use PLSY and D1220.) DVP-PLC Application Manual 2-116 Device No. Function D1232 Number of CH0 output pulses after mark Low word D1233 High word D1234 Number of CH1 output pulses after mark Low word D1235 High word D1236 Number of CH2 output pulses after mark Low word D1237 High word D1238 Number of CH3 output pulses after mark Low word D1239 High word Device No. Function M1170 Start flag M1171 Action flag D1170 STEP No. of the currently executed instruction Device No.
Function M1172 Switch for two-phase pulse output (On = enabled)