Brief analysis: Elevator monitoring system LMS and elevator networking technology

Today the topic of remote transmission of elevator control data (DFU) is more relevant than ever.

Increasingly expensive personnel costs and the continuous reduction in market prices for electronic components have prompted efforts to rationalize the use of the latest microprocessor and telecommunication technologies. Therefore, it is increasingly important to reduce travel time for maintenance personnel and to simplify fault diagnosis.

Therefore, people have put forward such requirements for many microprocessor control systems on the market: they have DFU functions, are intuitive, and can provide multiple possibilities for maintenance and error diagnosis.

What details are included behind the concept of DFU? What is the traditional elevator DFU system like? What is the current status of the technology? What are the advantages for operators and maintenance companies?

These questions will be answered using the elevator monitoring system of NEW-LIFT as an example.

1. Traditional DFU system

1.1 Functionality

Traditionally, DFUs are installed by connecting one or several control devices directly to a control center (ZLT) via the telephone network or by making a direct line connection (mostly in series).

In most cases the control center has a computer that can be used to store, monitor and analyze the most important parameters of a specific device. This involves both real-time values ​​and statistical data. These functions are often called remote monitoring or surveillance.

There is also the possibility that the control center actively participates in the control, the so-called "remote control" function. Various PC programs make it possible to manage all functions. According to the understanding of "DFU capability", the control device has one or several continuous relay areas, via which the control device can be continuously connected to the center. In this case, the individual devices have different communication protocols, which are often customized. In most cases, compatibility with other external control devices or building control units is not guaranteed. The use of NEWLIFT control devices (FST, KST and EST) will make any form of conventional DF? feasible and the use can be diversified.

1.2 Topology

The topology of the traditional DFU system is affected by many point-to-point connections between the control device and the main control center. Therefore, it is necessary to install a star connection line connected to the main control center. The central computer must have some corresponding switching equipment for internal management or be able to achieve hardware conversion with individual devices.

If each elevator control device has a modem connected to the telephone, it can replace the expensive point-to-point cable connection due to the internal or public telephone network and the line length limitation.

However, the disadvantages of this DFU topology are obvious:

Only one device can be connected from one control center, and monitoring of one device or many devices in the entire building at the same time is impossible.

There are non-negligible costs for lines, signal amplifiers, modems and telephone connections.

The simultaneous connection with multiple control devices is limited. For example, it is not practical to transmit a fire alarm to all control devices, and a fire alarm must be sent to each control device separately.

2. Current state of technology

Other avenues in building management engineering were explored long ago.

The key here is to implement state-of-the-art Feldbus networking. The networking of elevator controls will use a standard Feldbus as a transmission tool, just as it is widely used in lighting systems, access control and fire alarm equipment.

Compared with the traditional DF? system, the main difference lies in the structure of the Bus. In contrast to many point-to-point connections, information is exchanged through a Fledbus. Each user has equal rights and can obtain all information. The receiver can clearly identify the sender of each message based on the address. Using this common data medium provides a variety of functions for elevator management.

3. Structure of elevator monitoring system LMS

The elevator monitoring system LMS uses the LON Feldbus system to achieve networking of the entire building with NEWLIFT elevator control devices. This LON technology is the communication standard for building management projects established worldwide.

This connection is referred to below as LMSBus and can be realized via different media (fiber optic, twisted pair or radio).

For LMS-Bus, the use of optical fibers is preferred for many reasons:

* Highest data security due to perfect EMV and lightning protection

*Sufficient line length to achieve high transmission rate

*Potential isolation

The ring structure of the fiber optic Feldbus has made a great contribution to ensuring data integrity. For example, the damage of individual lines does not affect the bus, because the damage is automatically identified and located. Each user can obtain his information bidirectionally through the ring topology.

As an example consider a building complex with elevators equipped with different control systems: Newlift modules (GST), Newlift individual drivers (FST and KST) and external control (X-type).

All control devices are connected to the LMSBus via a PAM, which is responsible for both the conversion of application data records and the matching of different physical media to the LMSBus.

PAM can be configured in different software and hardware, and is therefore suitable for different types of control systems.

A PC (LMS-PC) is also connected to the LMS-Bus via PAM. The LMS software CAMPUS is a Windows 95/NT program on the LMS-PC. It displays all functions of the monitoring. It controls the data flow on the LMS-Bus behind the scenes with remote control and data analysis. This allows for optimal utilization of the bus.

In addition, an external LMS computer can be installed at the network interface through a modem, so that all the functions of LMS can be used anywhere (such as a maintenance office).