Chapter 2 Devices 10. The initial clock pulse SM404~SM410, and SR409~SR410 The PLC provides seven types of clock pulses. When the PLC is supplied with power, the seven types of clock pulses act automatically. Users can set the interval of the clock pulse in SM409 and SM410. The clock pulses are illustrated as follows.
10 ms 100 Hz SM404 (10 ms) 5 ms 100 ms SM405 (100 ms) 10 Hz 50 ms 200 ms SM406 (200 ms) 5 Hz 100 ms 1 sec SM407 (1 sec) 1 Hz 500 ms 2-81 Device Function SM404 10 millisecond clock pulse during which the pulse is ON for 5 milliseconds and is OFF for 5 milliseconds SM405 100 millisecond clock pulse during which the pulse is ON for 50 milliseconds and is OFF for 50 milliseconds SM406 200 millisecond clock pulse during which the pulse is ON for 100 milliseconds and is OFF for 100 milliseconds SM407 One second clock pulse during which the pulse is ON for 500 milliseconds and is OFF for 500 milliseconds SM408 Two second clock pulse during which the pulse is ON for one second and is OFF for one second SM409 2n second clock pulse during which the pulse is ON for n seconds and is OFF for n seconds The interval n is specified by SR409.
SM410 2n millisecond clock pulse during which the pulse is ON for n milliseconds and is OFF for n milliseconds The interval n is specified by SR410.