Add:Huishan District, Wuxi City, Luo town, Yang City, North West Road
SIEMENS S5 series PLC is currently in the industrial market in China, there are mainly U type (common type), W type (word processing type), R type (switching type), and other three models. Different types of PLC, the failure of the performance and the way to judge is also different. Among these, the software fault can solve the problem by using Siemens special programmer, Siemens PLC left PC communication interface, through a dedicated servo programmer that can solve the problem of almost all of the software.
Through the PC software program can determine whether the software fault, if it is a hardware failure, you need to special chip level circuit board maintenance engineer to repair work PLC are generally modular structure, relatively simple approach is to replace the board fault.
1, soft fault judgment and processing
S5PLC has the ability of self diagnosis, the module function error is often able to alarm and according to the response of the pre process, through the fault indicator light can be judged. When the power supply is normal, the indicating lamp also indicates normal, especially the input signal is normal, but system is not functioning properly (output or chaos). After the purpose of from easy to difficult, first the soft hard maintenance principle first check the user program whether there will be a problem. S5 in the user program stored in the ram of the PLC, power down volatile, when the mishap occurred in battery backup power system failures, the possibility of missing or disorder on the great, of course, strong electromagnetic interference will cause program error. With EPROM memory card slot PLC recovery procedure is quite simple, the program copy EPROM cards back to the PLC generally can solve the problem; no EPROM card users to use PG online function will correct program is sent to PLC. Need special note is that sometimes simple program coverage can not solve the problem, then in the re copy of the program before the total clearance of RAM in the user program is very necessary. The PLC on the "run" and "ST" according to RUN---ST---RUN---ST---RUN order call again or to perform "object - blocks, Delete---inPLC - allblocks---overall - reset" in PG is complete ram program clear for switch. In addition, stored in the EPROM program and is not foolproof, excessive trust in EPROM program sometimes confusing to the maintenance. So often check the EPROM in the program, especially in the PG backup program is particularly important.
2, PLC hardware failure
PLC hardware failure can be found more intuitive, the basic method is to replace the replacement module. According to the fault indication lamp and fault phenomena, the key of the maintenance is to judge the fault module.
1) power module fault
A normal work of the power module, the above work indicating lamp such as "AC", 24VDC "," 5VDC "and" batt "green light, which a light color changes or flashing or extinguished said that part of the supply problems. "AC" lamp indicates the total power supply of PLC, "AC" when the light is not bright, most of the working power supply, the whole PLC. Then you should check the power supply fuse is blown, replacing the fuse is with same specification and same type of fuse applications, without the same type of import fuse to with the same current fuse instead of. If the circuit board is short circuit or damaged, replace the whole power supply. "5VDC", "24VDC" lights out no corresponding DC power output, when the power supply deviation exceeds the normal value of 5% when the indicator light flashes, while the PLC can still work, but should be paid attention to, when necessary downtime. The "BATT" color changing lamp is the backup power indicator, the green is normal, the yellow power is low, and the red fault. Yellow light when it should replace the backup battery, manual provisions two to three years to replace the lithium battery once, when the red light indicates that the backup power system failure, but also need to replace the entire module.
2) I/O module failure
The input module is composed of a photoelectric coupling circuit, and the output module is based on the different models of the relay output, the output of the transistor, the output of the photoelectric and the like. Each point of the input and output has a corresponding light emitting diode indicator. There is an input signal but the point is not bright or determine the output but the output light is not bright it should be suspected that the I/O module is faulty. Input and output modules have 6 to 24 points, if only because of a point of damage on the replacement of the entire module in the economy is not cost-effective. The usual practice is to find alternate points instead, and then change the corresponding address in the program. But to pay attention to, when the program is difficult to find the specific address. Special emphasis is that, whether it is the replacement of the input module or the replacement of the output module, are in the case of PLC power outages, S5 plug-in module is absolutely not allowed.
3) CPU module failure
CPU module of universal S5PLC often include communication interface, EPROM slot, an operation switch, fault more subtle, because the replacement cost of CPU module greatly, so the fault analysis, judge to be particularly careful.
Repair example: a PLC with the power supply can not be transferred to the RUN state, the error indicator lights flashing lights, after the power failure is still, the replacement of the CPU module after the normal operation. In the chip level maintenance to replace the CPU but the fault lamp is still flashing, to replace the communication with the board after the function to return to normal.
3, peripheral circuit fault
According to the literature, in PLC control system failure rate: 5% of the CPU and memory, I / O modules accounted for 15%, sensors and switches accounted for 45%, actuator accounted for 30%, wiring and other aspects of 5%, visible more than 80% of the fault appears in the periphery circuit. Peripheral line routing field input signal (such as the button switch, select switch, close to the