Weak current College】 【Hitachi elevator computer by elevator failure severity is divided into five categories:.

The first type: the most serious faults, Elevator stop now, no longer start, but if you are in the entrance area of the switch. Usually such failures include: safety device failure, communication between the host computer failure, the main circuit overcurrent, overvoltage and cabin and control screen of serial communication failure. The second category: operation of elevator stop now, but you can restart, do one of the low-speed self-help to low-speed operation of elevator to the most recent layer opens the door to release passengers. If sync location error, elevator to run to the end at low speed, auto-correction level synchronization. Such failures are: deceleration exception, synchronous position error, computer selected layer for counting errors, forced deceleration switch stick death, etc. The third category: operation of elevator immediately to the nearest station is docked, stop after no longer start. Such failures are: flat layer of long, high power transistor heatsink overtemperature, etc. Category 4: parallel or group control system failures, etc. Such a failure occurs, the elevator automatically clears the parallel or group control management system and become independent operation of the lift and carry out assistance services. Category 5: belong to small failures, faults with contingency, automatic discharge after may, on the safety and the overall effect of subtle run. For this type of failure record computer only and not to take action. Such failures are: open, closed, start frequency overload, failure load compensation, etc.

1. important signal of safety testing

Elevators are important safety signals such as safety clamp switch, security window switch, sedan and car top emergency stop switch, limit switches, Builder switching components of emergency stop signal, and the door interlock switch, compulsory deceleration switch, limit switches etc are sent separately by FIO Board and Deputy Principal computer-computer. The host computer through the parallel communication between the exchange of information, as long as one of the parties do not receive a signal, or compare two parties in the communication signals of different will make an immediate emergency stop or elevator for phase is processed. 2, relay, contactor fault detection

Relays and contactors in the PC-driven suction or release, or if you contact adhesive does not snap-action action, it is possible that the elevator is not working, or even cause a major accident. So for important devices, their contact signal back to computer, computer in driving their pick-up or release, the judgement whether the action of the device, can figure out a good pick-up failure or fault free. This class of devices such as door interlocking relay, main circuit contactor, brake contactors, etc.

3. main circuit fault detection

The main loop detection includes over-current, over-voltage, under-voltage, etc. Overcurrent detection is accomplished through the DC circuit on the Hall-current transformer, detects the current with the given values are compared to determine whether the overcurrent. Over-voltage, under-voltage detection is in DC circuit set voltage detection points. Located over voltage, under voltage comparison circuit, the elevator runs, the DC circuit voltage must be within two comparison circuit set value range. Exceeded, the excess voltage; below the set value is less voltage. In the elevator when idle, microcomputer systems can also be detected on the capacitor, at this point, bring lifts ban on running for a few seconds, the exciting current of the motor to join, capacitor discharge by the motor, the voltage should be reduced, if the capacitor voltage does not decrease, then the capacitor is damaged.

4, computer communication review

Computer communications, regardless of the cabin and control screen of serial communication, or main, Deputy parallel communication between computer, each batch of data communication with data issues a different code, communication back and forth in time, if the emitted code and receive code will be similar to processing: serial communication can give up a batch of data, but as long as the two would make the elevator stops; parallel communication only once is the elevator stops running.

5. run direction detection

Pulse encoder with motor rotation produces two phase Pulse, direction distinguishing circuit detects the direction of the operation of the elevator. If the computer running direction instructions issued and direction distinguishing circuit is different, namely judgment to reverse running, lift immediately stop, record-keeping by computer malfunction, Elevator can no longer start, even if they pull off the power switch does not start again. Must be in fault is corrected, the Qing dynasty to fault logging can be up and running.

6, rotary encoder fault detection

For some device fault detection, you can set the time value judgment. Rotary encoder fault method: elevators Starter runs, a certain amount of time has not received pulse input. Of course, did not receive a pulse of reason does not uniquely identify a pulse encoder problems, but in the field of fault detection, General guidelines is to confirm the computer system itself is normal, as on the external device to be checked.

7, save multiple

Elevator operation fails and the emergency stop, if the category is not high, the computer will make the elevator to driving-speed run self-help, to leveling area release passengers, then resume normal operation. If by chance, the elevator will return to normal operation; if the cause of the malfunction, self-help occurs again. In a specified time, the number of occurrences of self-help exceeds a certain value, will judge for ourselves into multiple, smaller high school class of fault, the elevator stops running.

8, hyper-dynamic frequency overload

If in a specified time, the number of elevator frequently starting, exceeds a certain value, the judgment is starting frequency overload. At this point by the microcomputer control, elevator will automatically reduce the frequency, extension running on each floor of the stop time, protect the system. At the same time credited to fault table, indicating that the elevator has been overclocked degrees.

9, vice principal, mutual seizure of computer rooms

As a result of the master, Deputy in the elevator computer structure, work process, master, Deputy microcomputer mutual checks. If one computer has failed and the bogs, another computer will crash a computer and then start. If it works, the elevators continue to run unaffected, but the failure will be logged. But if over a certain period of time exceeds a certain number of stops, you go to high school classes of failure, the elevator at the final standing flat layer, open the door back can no longer start, and must beMaintenance personnel checked.