1. The MPU or the unit of expansion at the front, there is a POWE” LED. The LED will be on when the MPU is powered On. If the sign is not on when the MPU is powered up, it revenues that there is some difficulty with the power supply of DC PLC, and it is therefore significant to make sure whether the wirings of the terminals of +24V and the 0V are conducted correctly. If the ERROR LED is blinking quickly, it revenue that the power supply of +24V to the PLC is inadequate.
2. If the other sign, “L. V”, that places at the front of the unit of expansion is on, it income that the power voltage of input to the unit expansion is inadequate, and the output from the unit of expansion should be forbidden.
1. Ensure that the I/O wiring and the power wiring are both conducted correctly before the power is switched On. And be directed not to supply AC220V or AC110V into the terminals of I/O, or it may short circuit the wiring and would cause break to the PLC.
2. After using the devices of peripheral to write down the program into the MPU and that the MPU ERROR LED is not on, it ways that the program in utilize is reasonable, and it is currently waiting for the user to offer the command of RUN.
3. Use HPP to perform the forced test of On/Off of the contact output.
Operation & Test
1. If the MPU ERROR LED is not flickering, use the device of peripheral to offer the command of RUN, and the indicator of RUN will then be on.
2. HPP could be used to check the settings and the values registered of the timer, the data register and the counter during operation, and furthermore, to strength the contacts of I/O to conduct the motion of On/Off. If the ERROR LED is on, but it is not blinking), it means that the user’s program setting has go beyond the overtime limit of preset, and users must double check the program and carry out the function of On/Off again.
The PLC I/O Responding Time:
The total PLC responding time from the input signal to the motion of output is computed as follows:
Responding Time = user’s program scan time + output motion delay time + input interface delay time