(5) input / output board should be removed before the first turn off the mains, but if the production of necessary I / 0 boards can be removed at run-time programmable controllers, but the CPU board QVZ (overtime) lights; 

(6) pluggable template, to be more careful, gently, and the goods shipped out of static electricity; 

(7) the replacement of components not live action; 

(8) Maintenance must be placed after the template installed in place 

Second, installment and wiring

(1) The power line, the pilot wire as well as the PLC power line and the I/O line should distinguish the wiring, between the insulating transformer and PLC and I/O should use the double rubberized wire connection.

(2) PLC should be far away from the strong jamming source like electric welding machine, the high efficiency silicon rectifier unit and the large-scale power equipment, cannot install with the high-pressured electric appliance in the identical switch cabinet.                

(3)  The input and output of PLC are best separate the line, the switch quantity and the simulation quantity must separate the placing. The simulation quantity signal's transmission should use the shielded wire, the shielding layer should an end or the both sides earth, and the earth resistance should be smaller than the shielding layer resistance 1/10.              

(4)  The PLC elemental area and the expansion unit as well as functional module's ties cable should lie alone, prevents the outside signal the disturbance.

(5)  The exchange output line and the direct-current output line do not use the identical root electric cable, the output line to be far away from the high tension line and the power line as far as possible, avoids parallel. 

Third, I/O end wiring 

1. Input wiring 

(1) inputs the wiring not to surpass 30 meters generally. But if the environment disturbance is small, when the loss of voltage is not big, the input wiring may suitable long. 

(2)Inputs/the output line not to be able to use the identical root electric cable, the input/output line to be separated. 

(3)Uses the normally opened contact form to connect the input end as far as possible, causes the establishment the trapezoidal chart to be consistent with the relay schematic diagram, is advantageous for reading. 

2. Outgoing junction 

(1) The out-put wiring pides into the independent output and the public output. In not group, may use the different type and the voltage class output voltage. But can only use the identical type, the identical voltage class power source in the identical group's output. 

(2) Because the PLC output element is sealed on the print circuit wafer, and connects to the terminal strip, if will connect output element's load short circuit, will burn down the print circuit wafer, therefore, application fuse protection output element. 

(3)Uses when the relay outputs, withstands inductive load's size, will affect relay's service life, therefore, time use inductive load the selective relay working life must be long. 

(4) The PLC output load possibly has the disturbance, must therefore take the measure to control, if direct-current output's after flow guarantees protects, the exchange output anti- accommodates the absorbing circuit, the transistor and the bidirectional thruster output by-passed resistor protection.

Fourth, PLC earth the good earth is guaranteed that the PLC reliable work the important condition, may avoid the heterogametic the voltage surge harm. PLC meets the grounding and machine's ground terminal docking, meets the grounding the cross-sectional area should not to be smaller than 2mm2, the earth resistance is smaller than 100Ω; If must use the expansion unit, its ground point should accept after checking with the elemental area earth in the same place. In order to suppress adds in the power source and the input end, out-port's disturbance, should joins the special-purpose grounding to PLC, the ground point should with the power equipment (for example electrical machinery) the ground point separate; If cannot meet this kind of requirements, must achieve with the other equipment public earth, forbids to establish contacts the earth with other equipment. The ground point should approach PLC as far as possible.