Most of the hardware faults of PLC on the glass tempering furnace are caused by periphery ones, for the processor can inspect itself constantly during the runtime of PLC and the problems on its own would be alerted by the panel light. Most of the troubleshooting operations start from I/O interface and extend to the connection wiring, the connection terminal and the connecting components. The general troubleshooting procedure is as follows:

1. Check the power supply to make sure the indicator is power-on which shows the power supply of PLC is ok.

2. Check the plug of the I/O module to eliminate the plug malfunction.

3. Simulate the input signal of the electrical components and check if the input channel works well. If not, try the alternatives and the program address should be revised accordingly after replacement. And remember to replace the module if too many channels are damaged.

4. Connect it to the PC and force output online and check if the output channel is in its normal state. If not, try the alternatives and the program address should be revised accordingly after replacement. And remember to replace the module if too many channels are damaged.

5. Check the electrical components to see if they are in the normal state. If not, replace them as soon as possible.

6. Check the input power of the electrical components.

The maintenance and troubleshooting of PLC is also related to the specific PLC. Proficiency of PLC operating requires more routine access. An effective troubleshooting way requires more practice. What also helps is the experience from the other people, which plays a more important role and is more effective than theory. Besides, more exchanges are recommended among the peers to share skills and methods.