1. System Architecture

Stuf-280T heat meter uses M-BUS to communicate with a host, such as an M-BUS concentrator or a data center, for metering readout. M-BUS system is an European instrument bus standard designed for domestic metering devices, such as water meter, heat meter, gas meter, etc., to communicate with data center. The bus simply uses two non-polarized wires to achieve a variety of options for reliable meter reading, remote diagnosis, remote control, incremental pricing, time-based pricing, batch service, prepaid billing, and etc. This bus system is also simple and economical to wire and construct.

A typical automatic meter reading system (AMR) is consisted of a number of Stuf-280T heat meters, an M-BUS concentrator, and a data center (Figure 1). The data center is actually a computer running data management software.

The Stuf-280T heat meters communicate with the M-BUS Concentrator through the two-wire M-BUS. The concentrator communicates with the data center computer through RS232 interface directly. Data center first sends out a meter reading command, either individual reading command or group reading command, to the concentrator. When the concentrator receives the command, it interprets the command and sends queries to the specified heat meter or heat meters. The heat meter(s) will then send back the requested data to the concentrator, which packs the data and sends it to the data center for saving, printing, searching, billing and etc.

In order to make the system working efficiently, we normally recommend to have no more than 256 heat meter units under one concentrator. To make a larger metering system, one can use M-BUS relays which we provide. Each concentrator can connect to up to 256 M-BUS relays, and each relay can connect up to 256 heat meters or relays.

A typical remote automatic meter reading system (RAMR) system is consisted of a number of Stuf-280T heat meters, several M-BUS concentrators, a DTU GPRS transceiver for each M-BUS concentrator, and a data center (Figure 2).

The M-BUS Concentrator communicates with the data center computer through GPRS network. The data center first issues a meter reading command and sends it to the network. The DTU receives the command and forwards it to the concentrator. The following process is similar to the one explained in the previous section.

To expand the RAMR system, you may deploy a number of DTUs and have a single data center to manager those DTUs and their subsystems. Our Data Center Manager PC software is designed for this purpose. Please refer to later sections for details.

2. System Functions and Features

• Group meter reading
• Individual meter reading
• Scheduled meter reading
• Metering data process
• Meter management
• Time adjustment
• Battery voltage monitoring
• Remote diagnosis
• Non-volatile memory for safe data storage
• Automatically detecting on-line meters
• Multiple meter reading plans to select
• Able to export metering data in standard format or user-defined format. Those data can be used by third-party billing software or data management software
• Able to implement standard billing as well as prepaid billing methods. Note that the prepaid method requires control valve to be installed. Tariff schedule can be customized upon request.
• Low power consumption design, which allows the Stuf-280T heat meter to work for 5-6 years with its built-in battery
• The two-wire bus not only carriers the data, but also provides power to the heat meter. This saves time and money for system cabling
• The bus does not have polarity, thus, easy to connect and convenient for system integration

• Hierarchy system architecture makes district heat management efficient, robust and scalable

3. M-BUS Concentrator

As mentioned earlier, M-BUS concentrator is responsible for data collection from heat meters in a certain region. It packs the data and sends it to back to data center.

M-BUS concentrator has also powerful networking and monitoring capabilities. It can communicate with both GPRS DTU device and Stuf-280T heat meters. It converts RS232 protocol to M-BUS protocol in real-time fashion.

Concentrator Features:

Meter reading

The concentrator can automatically collect data from the local heat meters according to a preset address table (physical address) at a preset schedule or upon request. It saves the data in its local memory. It also sends the data to data center.

Transmit data upward, transfer commend downward

The concentrator sends metering values up to data center, and transfer commands down to heat meters. It can also forward valve control command to a specific valve to open or close the valve.

Large non-volatile memory

The concentrator has a large non-volatile flash memory for data storage. This prohibits data lost after power shut-down.
The concentrator also stores the heat meter addresses, data center address and protocol parameters.

Powerful communication capabilities

The concentrator is able to communicate with data center through RS232 link or GPRS network. On the other side, it communicates with heat meters or M-BUS relays through M-BUS

Self-diagnosis and self-protection

The concentrator is able to diagnose any short-circuit problem on its M-BUS. When it finds a heat meter short-circuited with the concentrator, it sends an alarm together with the meter address to data center immediately. This provides a convenient way for operator to locate the site and fix the problem quickly. Besides, this alarm can be used to prohibit stealing or water leakage.

When short-circuit occurs on the bus, the concentrator will enter into self-protection mode. After a certain amount of time, it will try to connect to the heat meters again. If still not successful, human intervention is needed to fix the bus problem. After the problem is solved, a reset to the concentrator will put everything back to normal.

Automatic meter reading

The operator just needs to set up a schedule on what time and to what clients he wants to read the meter values, and the concentrator will do the rest automatically. Reliable and efficient. No need to have people to knock the clients’ door. Saves money and time.

4. Data Center

4.1 Hardware System Minimum Requirements

• CPU: Pentium 166 200MHz
• Memory: 64MB
• Hard Drive: 500MB
• Display: Resolution 1024x768, Color 256

4.2 Software System Minimum Requirements

• OS: Windows 2000 or above
• Database: Microsoft SQL Server 2000 or above
• Application software: Shenitech Data Center Manager
• The following sections will focus on the Data Center Manger software.

4.3 Hierarchy Heat Management Architecture

Based on many years’ meter reading experiences, we established a hierarchy heat management system architecture which is flexible, scalable, reliable and robust (Figure 4.) This architecture has been fully implemented in our Data Center Manager software.

There are four layers in this software topology, top later is for DTU management, middle upper layer is for area management, middle lower layer is for building management, and bottom layer is for client management. A DTU region could have several Areas, an Area could have many buildings, and a building could have many clients.

4.4 Main Graphic User Interface

Figure 5 illustrates the main graphic user interface of the Data Center Manager software. There are mainly five information groups in this interface, login info group, meter reading info group, client selection group, client info group, code input group and status group.

There are 6 sub menu windows, Service Control, System Setup, DTU management, Data Center, Area management and Help.

Service Control Menu:

Before you can read meter data, you need to start the service and establish the connection first by selecting the “Start Service” option. Click “Exit” if you want to disconnect the meters and exit the software.

System Setup:

To configure the system, select “System Setup” -> “Service Parameter Setup”.
The service can be turned ON only when the service parameters have been set up.

DTU Management:

This menu is for GPRS remote access only. The parameters of the DTU device should be configure here.

Area management:

This menu allows user to add new area in to a DTU region.

Building management:

Select Area->Building from the main user interface will open the following menu to add new building into a certain Area.

Data Center:

This menu is for client registration, log-in control, meter reading information query, account information query and print.

(1) Client Information

Select Data Center->Client Info from the main user interface will open the following menu. User can add new clients, search for existing clients, etc.

(2) Meter Reading Information

Select Data Center->Meter Reading Info from the main user interface will open the following menu. User can view and search the meter readings from a specific client.

Shenitech can customize the software according to our customer’s specifications.

For other software, such as billing software, please contact Shenitech at support@shenitech.com.