5466-348 Woodward Control System Integrity Service

Description

Features

• With one driver per port, the update rate for critical parameters is 5 ms.
• Interface for Digital Actuator Drivers
• Each RS-485 port can operate at a different rate group.
• Each driver’s communication fault is detected, and drivers with comm faults are disabled.
• Remote monitoring of driver parameters
• Remote driver parameter configuration
• Allows the drivers to issue a fast and very accurate position command (16 bits, no noise).

Application

• It can send position demand and configuration information to the driver while also monitoring the driver status outputs.
• It is capable of configuring the driver and monitoring the status outputs, but not of sending a position demand. The demand for driver position would come from a 4- 20 mA input or the CAN bus interface.
• It can be used to monitor the driver’s status outputs but not to configure or send a position demand to the driver. The driver position demand could be generated by a 4-20 mA input or by the CAN bus interface, and the configuration input could be generated by RS-232 or by the CAN bus interface.

The elevator control system mainly consists of a speed regulation part and a logic control part. The performance of the speed control part plays an important role in the comfort of passengers during elevator operation. Currently, high-performance frequency converters are mostly used to measure the traction motor speed using rotary encoders, forming a closed-loop vector control system. By setting the parameters of the frequency converter reasonably, not only does the elevator have protection functions in terms of running over speed and under speed, but also makes the start, low speed operation, and stop of the elevator more stable and comfortable. The starting, stopping, and motor speed selection of the frequency converter itself are all completed by the logic control part. Therefore, the logic control part is the key to the safe and reliable operation of the elevator.

The V80 series PLC has been applied in elevator production and renovation in multiple elevator manufacturers due to its high reliability, fast computing speed, low product cost, and customized elevator services. This article takes a villa elevator control system with four floors and four stations as an example to explain the design concept and implementation scheme of V80 series PLC in the elevator control system.
Composition of elevator control system.

The elevator control system is mainly composed of a frequency conversion speed control main circuit, input/output units, and PLC units, used to manage and control the start, acceleration/deceleration, stop, running direction, floor display, floor call, cabin operation, safety protection and other command signals of the elevator traction motor and door opening/closing machine.

The main circuit of variable frequency speed regulation is composed of three-phase AC input, variable frequency speed regulation drive, traction machine, and braking unit. The frequency converter adopts the vector controlled elevator special frequency converter 616G5 from Japan’s Yaskawa company, which has good low-speed operation characteristics and is suitable for application in elevator control systems.
The three-phase power supplies R, S, and T enter the frequency converter through wiring terminals to supply power to its main circuit and control circuit. The output terminals U, V, and W are connected to the fast winding of the motor, and the external braking unit reduces braking time and accelerates the braking process. The rotary encoder is used to detect the running speed and direction of the elevator.

The frequency converter compares the actual speed with the given speed inside the frequency converter, thereby adjusting the output frequency and voltage of the frequency converter, so that the actual speed of the elevator follows the given speed inside the frequency converter, achieving the purpose of adjusting the elevator speed. The input signals of the frequency converter are: up and down direction commands, zero speed, crawling, low speed, high speed, maintenance speed and other speed coding commands, reset and enable signals. The output signal of the frequency converter is:

(1) the ready signal of the frequency converter. When the frequency converter operates normally, notify the control system that the frequency converter can operate normally;

(2) Signal during operation, notifying the PLC that the frequency converter is outputting normally;

(3) Zero speed signal, when the elevator running speed is zero, this signal output is effective and notifies the PLC to complete actions such as holding brake and parking;

(4) Fault signal: When the frequency converter malfunctions, this signal outputs effectively and notifies the PLC to respond, powering off the frequency converter.