PLC breakdown is common reason and processing technique

Breakdown of the first PLC in moving partly is common reason and processing technique (one) periphery circuit yuan this kind of breakdown is in breakdown of parts of an apparatus PLC job often happens in the breakdown after proper time. If appear,be in in PLC control loop breakdown of yuan of attaint of parts of an apparatus, PLC controls a system to be able to quit the job automatically instantly. Input is the port that PLC accepts the input signal such as switch quantity, imitate quantity, its means of the actor bad of quality of yuan of parts of an apparatus, wiring and whether the main factor that firm also is dependability of influence control system. To switch capacity output, the output of PLC has relay output of output, brilliant brake canal, transistor outputs 3 kinds of forms, specific choice the output of which kinds of form should decide according to laden requirement, choose undeserved meeting to make systematic dependability is reduced serious when bring about a system to cannot work normally. In addition, it is finite that the output terminal of PLC brings laden capacity.

What if exceeded,set is the biggest be restricted to be worth.

Must outside receive relay or contactor.

Ability works normally. The quality of the executive component such as a powerful person of relay, contactor, electromagnetism is received outside, it is the main factor that affects systematic reliability. Wired circle short circuit, mechanical failure causes common breakdown to contact is not moved or be contacted undesirable. (2) terminal wiring contact is undesirable this kind of breakdown works in PLC lift as the frequency of equipment movement after proper time appear. Because control ark layout blemish to perhaps be used,shake the reason such as aggravate and mechanical life mediumly, wiring head or yuan easy generation of column of wiring of parts of an apparatus becomes loose and cause a contact undesirable. Of this kind of breakdown eliminating a method is use avometer, principle of system of control of have the aid of pursues or graph of PLC logistic echelon undertakes breakdown diagnoses maintenance. To certain the wiring of mainer peripheral wiring terminal, to assure reliable join, use commonly solder cold sheeting or cold press the methodological processing that inserts a needle. (3) all sorts of type PLC that use in the system of automation of functional sex breakdown that PLC is caused by interference, it is the control equipment that produce an environment technically for industry and designs. Used in design and making a process mutiple level interference rejection and handpick component measure, reason has the stronger capability that gets used to abominable industry environment, moving stability and higher reliability. Because this is general,do not need what to adopt special measure can be in directly industrial environment is used. The interference that PLC gets can be divided disturb for exterior interference and interior. In actual production the environment falls, exterior interference is random, have nothing to do with construction of system, and interference source is cannot eliminate can try to restrict in the light of particular case only. In-house interference and construction of system are concerned. Basically measure input signal to wait through main circuit, imitate communicating inside the system cause, wait for processing through circuitry of elaborate design system or wave of systematic software filter, can make in-house interference gets the inhibition of utmost. The measure of interference rejection technology of PLC production site -- from power source and ground connection protection, wiring normally arrangement screen mixes fight 4 respects such as noise to begin to consider: (1) power source and the interference rejection ability that ground connection protects PLC itself are general very strong. Normally.

Part the power plant power source of the power source of PLC and system layout is disturbed to what power supply cord comes, have commonly enough strong inhibition ability. But electrical interference is particularly serious, can add the segregation transformer that receives to take screen layer in order to reduce the interference between equipment and ground, raise systematic dependability. If patulous unit is contained in a system, criterion its power source must as common as main unit a switch control, that is to say, their electrify and cut off the power must undertake at the same time. Add to restrain the interference that carries in power source and input end, output, should receive ground wire of special ground wire to PLC line means wants enough thick.

Ground connection resistor should be less than 4 Ω , ground connection dot should stand by PLC as far as possible, and accept a place should part with other equipment. To the strong report equipment in power supply system, the metallic component such as put oneself in another's position of its crust, cabinet, frame, baseplate and operation handle must protect ground connection. PLC in-house circuit includes CPU, memory and other interface to receive digital land in all.

Exterior circuit includes A/D, D/A to wait to receive imitate ground to use dumpy copper cash to prevent PLC motherboard and coupling of form of star of dot of central ground connection Duo sound to disturb in all. When PLC is not ground connection to work, answer to contain the installation stand of PLC sexual ground connection to be disturbed in order to restrain electromagnetism. (2) traditional thread binding of signal of the ability of line of imitate quantity input that wiring arranges road of electric ark planted agent to walk along a line to decorate ① to have screen only and digital amount is inside same line chamfer, line of amount of volts d.c. number and imitate quantity line cannot be together with alternating voltage line inside chamfer of a gleam of. The ability of 220V power supply cord that ② has screen only and signal traditional thread binding are inside same line chamfer. The screen of outlet of cable of ③ electric ark must reliable ground connection. ① of exterior arrangement taking a line sheds electric ark continuously and the digital amount line of alternating voltage and imitate quantity line must use independent cable severally, and should use screen cable. ② line cable can be installed jointly with power source cable inside chamfer of a gleam of, to improve the sex that fight a confusion of voices the proposal assures removed 10cm above. (3) the screen of crust of screen processing PLC, should assure commonly as empty as electric ark float. Add on PLC crust motherboard install to wait for a screen board (use) of plating zine plate commonly.

Wire of protective ground use copper and motherboard maintain a bit link its cut area should not less than 10mm, wait for a shield in order to form, remove the interference of exterior electromagnetism field effectively. The screen bus line that measures signal to imitate can be isolated from and reach central point referenced potential or ground repeatedly (on GND) . The number measures the cable two end earthed of line to be able to make sure better land removes high frequency interference. (4) the measure that fights noise is strong to be in magnetic field (for example transformer) the part should have metallic screen electronic-controlled should not be inside ark use illume of fluorescent lamps and lanterns. PLC controls systematic power source to also should adopt relevant interference rejection measure. The method of interference rejection of power source of PLC control system has use segregation transformer, low a filter and applied spectrum are balanced law 3 kinds. Keeping apart transformer among them is the most commonly used, the I/O module power source because of PLC is commonly used DC24V, beard classics keeps apart transformer step-down, furnish via rectification bridge commutate again, power source of direct perhaps use switch furnishs. (4) PLC is periodic dead machine PLC is periodic the feature of dead machine is PLC every run a certain number of time to appear dead machine or the program is troubled, perhaps appear to interrupt breakdown differently to show, after be being started afresh everything is normal. Think according to carrying out experience, this phenomenon is the commonnest because PLC airframe accumulates ash for long to cause,the reason is. Answer to insert groovy interface place to undertake blowing sweeping to PLC frame regularly so. Blow when sweeping, can use first compress air or down to brush get on control plate, the dirt in inserting groove each is blown sweep clean, 95% alcohol rub-up inserts reoccupy groove and control plate outlet. Sweep after ending careful examination, restore to switch on the mobile phone to be able to move normally. Because undesirable wiring has ground contact,PLC program loses is normally by accident, the account that handles a few sides such as error and interference causes: 1, PLC lead plane and module must have good ground contact. 2, the look line of lead plane power supply cord and neuter line must wiring is correct. 3, package of beforehand good program, use as backup. 4, use hold process designing implement when searching breakdown, should decide the lock switch park perpendicular position, pull out the function that can have to protect memory. 5, because the reason of interference creates PLC program,lose.

Its processing technique can consult the processing that PLC suffers interference to cause trouble. Breakdown of PLC of the 2nd part searchs flow chart NO.

1 overall examination finds out the general orientation that breakdown nods according to overall examination flow chart, refine gradually, in order to find out specific breakdown, following plan institute are shown. NO.

Light of power source of examination of breakdown of 2 power source is not bright need to undertake checking to power supply system, following plan institute show examination flow chart. NO.

Power supply of examination of 3 operational failure is normal, moving indicator light is not bright, demonstrative system already was planted because of some unusual and it is normal to was stopped move, following plan institute show examination flow chart. NO.

Output of input of examination of breakdown of 4 inputs output is the channel that PLC and peripheral equipment have information communicates, whether do its work normally, besides outputting unit to concern with the input, still wait for component condition to concern with canal of terminal of connection layout, wiring, insurance. Following plan institute show examination flow chart. CNC Milling