Chapter 6 Applied Instructions 6.7.2 Explanation of I/O Refreshing Instructions Symbol D ： I/O point state to refresh n ： Number of I/O points states to refresh Explanation 6_ 1. The I/O states are normally not refreshed until the PLC executes the END instruction. When the PLC starts scanning the program, it reads and stores the states of the external inputs in memory. After executing the END instruction, the PLC sends the states of the outputs in the memory to the output terminals. Therefore, when you need the latest I/O data during the operation process, you can use this instruction, or use the device DX/DY to refresh the input/output. Note:
the immediate I/O updates only apply for I/Os of the CPU. 2. The operand n must be multiples of eight, such as 8, 16, 24 and up to 256. If the value here is less than a multiple of eight, it will be seen as the next multiple of eight. For example, the value 20 will be seen as its next multiple of eight, 24. 3. The number of the high-speed output point is stored in D device. If n is 1, it indicates to refresh the high-speed output value of the corresponding SR immediately. If n is 0, it indicates to stop high-speed output and refresh the SR current value.
For example, during the execution of this instruction, if n is 0 and the external interrupt input is received through X0, it indicates an external interrupt occurs in X0 and high-speed outputting through Y0 should be stopped immediately. The PLC sets the stop flag SM463 to ON and refresh the current corresponding output position in SR. Note:
if the output completion auto-reset flag is set to ON, the PLC sets the output completion 6-171 API Instruction code Operand Function 0600 REF P D, n Refreshing the I/O Device X Y M S T C HC D FR SM SR E K 16# “$” F D n BOOL WORD DWORD LWORD UINT INT DINT LINT REAL LREAL TMR CNT STRING Data type D n Pulse instruction 16-bit instruction 32-bit instruction ES3 ES3 －