English referred to as ICD, full name Industrial Communication Device. This
section will introduce the wired communication equipment and wireless
communication equipment applicable to industrial control environment in a
comprehensive way. Wired communications equipment
to address the industrial field of serial communication, professional
bus-based communications, industrial Ethernet communications and various
communication protocols between the conversion equipment. Wireless
communication equipment is mainly wireless AP, wireless bridge,
wireless card, wireless lightning arrester, antenna and other equipment. Telecommunication Casting Parts,Cable Anchor Clamp,Precise Casting Telecommunication Parts,Magnesium Casting Parts Ningbo Beilun Huari Metal Products Co., Ltd. , http://www.huari-metal.com
First, the soft failure of the judgment and processing S5PLC has self-diagnosis capability, the occurrence of module function error can often be alarm and respond according to pre-program, through the fault indicator can be judged. When the power is normal, each indicator also indicates normal, especially the input signal is normal, but the system function is not normal (no output or chaos), in the first easy after the hard, soft and hard after the first principle of inspection to check whether the user program appears problem. S5's user program is stored in the RAM of the PLC. It is volatile after power off. When the backup battery fails, the possibility of program loss or disorder is very high. Of course, strong electromagnetic interference can also cause program errors. . PLC recovery program with EPROM memory card and slot is quite simple. After copying the program on the EPROM card back to the PLC, it usually solves the problem; users without the EPROM daughter card will use the online function of the PG to send the correct program to On the PLC. It should be particularly noted that sometimes simple program coverage does not solve the problem. At this time, it is necessary to always clear the user program in RAM before copying the program again. Press “RUN†“ST†switch on the PLC and press RUN---ST---RUN---ST---RUN to dial once or execute “Object-Blocks-Delete---inPLC-†on the PG. The function "allblocks---overall-Reset" completes the program in RAM. In addition, the program stored in the EPROM is not foolproof, and it is believed that the program on the EPROM sometimes causes confusion for the maintenance. Therefore, in the maintenance technology of PLC power supply module, it is often necessary to check and verify the program in the EPROM, especially the backup program in the PG.
Example of maintenance technology for PLC power supply module: Once, a device that has been shut down for two months has problems and cannot be started after power-on. After the inspection, the engineer thinks that the program is in error. Naturally, the EPROM card is inserted into the PLC. After the program is completely cleared, the program is restarted. The fault persists. Since the program is not large, the program on the EPROM is read one by one, and the instructions on the manual are read. After checking, it was found to be exactly the same. If the duplicate copy is invalid, it is considered to be a PLC hardware failure. We use the PG to call up the backup program and compare it with the program on the EPROM. The result statement instruction table is the same, but the program storage address has changed. After the backup program is sent to the PLC, the device runs normally. It can be seen that the program on the EPROM has also encountered an error. After erasing with UV, the problem is rewritten.
Second, the external circuit fault According to relevant literature reports, the failure rate in the PLC control system: CPU and memory accounted for 5%, I/O module accounted for 15%, sensors and switches accounted for 45%, actuators accounted for 30%, wiring Such as other aspects accounted for 5%, we can see more than 80% of the fault appeared in the peripheral line. Peripheral lines are field input signals (such as push-button switches, selector switches, proximity switches and some sensor output switches, relay output contacts or analog-to-digital converter converted analog, etc.) and field output signals (solenoid valves, relays, contacts Devices, motors, etc.), as well as wires and terminals. Loose connection, component damage, mechanical failure, and interference can all cause peripheral circuit failures. Care should be taken when troubleshooting. Replacement components should use high-quality devices with reliable performance and high safety factor. Some powerful control systems use fault code tables to represent faults, which greatly facilitate the analysis and troubleshooting of faults and should be used properly.
Example of maintenance technology for PLC power supply module: The control system of an underwater pelletizer failed. The engineer found that no input from Q5.4 caused the output of Q7.0 and the pelletizer could not be turned on. After the inspection, it was found that the signal converter and the proximity switch were damaged at the same time and were normal after replacement. Such failures have a certain degree of concealment, and they need to be eliminated step by step with multimeters, system schematics, and logic diagrams.
Third, PLC hardware failure PLC hardware failure can be found more intuitively, the basic method of maintenance is to replace the module. Judgment of fault modules based on fault indicators and faults is the key to maintenance. Blind replacement will bring unnecessary losses.
1. The power module is faulty. A working power module has its upper working indicators such as “ACâ€, “24VDCâ€, “5VDCâ€, and “BATTâ€. It should be green and long, and the color of the lamp has changed. Or flashing or extinguished indicates that there is a problem with that part of the power supply. The "AC" lamp indicates the AC main power supply of the PLC. When the "AC" lamp is off, most of the power is not supplied and the entire PLC stops. At this time, it should be checked whether the power fuse is blown. Replace the fuse with a fuse of the same model with the same specification. When the imported fuse of the same type is used, replace it with a fast fuse with the same current. If the repeated burning of the fuse indicates that the board is short-circuited or damaged, replace the entire power supply. The "5VDC" and "24VDC" lights go out indicating that there is no corresponding DC power output. When the power supply deviation exceeds the normal value of 5%, the indicator light flashes. At this time, although the PLC can still work, it should be taken seriously, if necessary, shutdown inspection.
The "BATT" color-changing lamp is a backup power indicator. It is green, yellow, and red. When the yellow light is on, the backup battery should be replaced. The manual specifies that the lithium battery is replaced two to three years. When the red light is on, it indicates that the backup power system is faulty and the entire module needs to be replaced.
2. I/O module fault input module is generally composed of optocoupler circuit; output module has relay output, transistor output, photoelectric output according to different models. Each point of input and output has a corresponding LED indication. If there is an input signal but the point is not lit or if there is an output but the output light is not on, you should suspect that the I/O module is faulty. The input and output modules have 6 to 24 points, and it is not economical to replace the entire module if it is only because of one point of damage. The usual practice is to find alternatives and then change the corresponding address in the program. However, it should be noted that the larger program is difficult to find a specific address. It is particularly emphasized that whether the replacement of the input module or the replacement of the output module must be performed in the event of a PLC power failure. The S5 hot plug module is absolutely not allowed.
3, CPU module failure Common type S5PLC CPU module often includes a communication interface, EPROM slot, operating switch, etc., the greater the concealment of the fault, because the cost of replacing the CPU module is very large, so its failure analysis, judgment To be particularly careful.
Example of PLC power supply module maintenance: When a PLC is switched on, the switch cannot be switched to the RUN state. The error LED flashes and then remains on. After the power-off reset, the fault persists. After the CPU module is replaced, it runs normally. When the CPU was replaced at the chip level, the fault light was still blinking, and the function did not return to normal until the communication excuse board was replaced.
Summary:S5PLC has the self-diagnosis ability, when the function error of the module occurs, it can often alarm and respond according to the pre-procedure, and can be judged by the fault indicator. When the power is normal, each indicator also indicates normal, especially the input signal is normal, but the system function is not normal (no output or chaos), in the first easy after the hard, soft and hard after the first principle of inspection to check whether the user program appears problem.