HomeTop StoriesSE-240 - the modular open architecture meter

SE-240 – the modular open architecture meter

SE-240 – the modular open architecture meter

EPRI has designed and tested a new smart electronic residential meter that incorporates several features ideally suited to the needs of utilities in worldwide deregulated electricity markets.

Epri's New SE-240 Meter

The new meter, called the SE-240, has plug-in modules that allow utilities to offer different customer services and enable different entities to own the meter and the means to open access. What’s more, the SE-240 is the only meter on the market today that features an open architecture interface, which makes it possible for modules to be manufactured by any vendor. In addition, the SE-240 has imbedded ANSI C12.19 tables that allow two-way communications for digital information, high frequency current and voltage data, load profiles, demand data and security information.

Together these features will help utilities implement automatic meter reading (AMR) and offer value-added customer services such as real time pricing.

Thus far EPRI has produced over 100 SE-240 meters and has supplied them to 47 member utilities for testing, evaluation and comments. In addition meters have been provided to 19 vendors to use in developing modules for a range of services and in a series of communications media. EPRI plans to commercialise the SE-240 and to supply the meter to utility customers as part of its collaboration program.

METERING for profit

Many businesses today view deregulation as a new profit opportunity. A number of these opportunities centre around AMR and communications systems. Companies that are already installing communications infrastructure are competing aggressively for customers. They regard the AMR communications system as an important aspect of new services, such as home security and energy management services.

All these players need access to the meter and the data in the meter. However, most existing meters, which are predominantly electromechanical, are not equipped with communications of any kind. To enable AMR, these meters would generally have to be removed from the customer site and returned to the factory for retrofitting.

Other existing electronic meters generally have licensed AMR systems, and it is not easy to become a licensee.


The SE-240 is ideally designed to bridge the transition from a regulated utility to a deregulated marketplace. It is a form ‘2S’ (240V, 2-phase, 3-wire) meter, with a base unit and interchangeable, add-on modules. The base unit is manufactured by EPRI. The modules, which can be manufactured by any interested vendor, provide the capability for one-way or two-way remote meter reading and other advanced services (see fig 1).

Fig 1

The modular design meets a number of needs related to a deregulated market. The modules are designed to be plugged in easily at the customer site, without taking the base unit out of service. In this way the SE-240 resolves ownership and stranded asset problems, since the base unit can be owned by the regulated utility while the module can be owned by other entities.

The SE-240’s modularity also makes it AMR-ready. As a replacement for the electromechanical meter, it will never become obsolete; its modifiable nature makes it able to accommodate new functions as they are developed.

Modules offer flexibility to utilities by providing a choice of different communications media – radio frequency, telephone modem, cellular phone and power line carrier. With this capability, energy companies can use the most appropriate communications media.

The modules also make possible a range of customer energy services, including energy management, remote diagnostics, outage location, appliance monitoring, disaggregated billing, prepayment and power quality.


Thus far 19 module vendors have committed to developing modules that meet the open specification of the SE-240, and negotiations are ongoing with others. Here is a summary of work to date.

Table 1
Vendors with Modules Under Development for the SE-240
Vendor  Service
Cannon Technologies  Two-way communications
Cellemetry  Wireless communications
CIC Systems  Communications, billing, and payment services
DATAcquisition Technologies  GE Opticom compatible port
DBS Industries  Satellite communications
Domosys Corp.  CEBus, power line networking
Energy Information Tech  Itron-compatible module
eT Communications  Phone and wireless two-way communications
Gateway Technologies  Low-cost wireless
Hunt Technologies  Ultra-narrow bandwidth PLC
Innovatec  Two-way fixed network, LAN/ WAN/PLC
ISCDatacom  CATV/telephone
LaBarge  Wireless solutions
Leach Industries  Outage detection
Moore Diversified Products  CATV module + appliance control
Nexsys  Two-way wireless
nVision  Wireless technologies
Ohm Tech Labs  Modem-based solutions
Williams Telemetry  Telemetry Interface Modules (TIM) RF

Cellemetry Data Services uses the control channel of the cellular network, which is greatly under-utilised, to send and receive short bursts of data for AMR. This economical, two-way form of messaging can handle up to 32 bits of data, and offers on-demand meter reading using existing infrastructure. An inexpensive cellular radio that sends and receives data instead of voice is used. The cellular spectrum is also safe, and has been allocated by the FCC specifically for that purpose.

DBS Industries (DBSI) in an alliance with Alcatel, is developing an AMR system that employs Low Earth Oribiting (LEO) satellites. The company has obtained a licence to construct and launch six LEO satellites, able to monitor fixed assets and collect data from any location worldwide. The satellite-based system is ideal for AMR applications where metering sites are hard to access or where logistical issues (such as significant travel time, rugged terrain or safety risk) contribute to much higher meter reading costs.

The hard-to-access meter segment has been estimated at 17 million meters in the US, and 30 million meters worldwide. Combining the DBSI two-way communication device with the SE-240 meter provides a low-cost AMR solution. DBSI is planning to launch its LEO satellites in the second quarter of 2001.

Domosys Corporation, a leading provider of power line transceivers for control networks, is developing a LAN communication module for the SE-240 meter, which will create seamless, low-cost two-way communication between the transformer on the pole and multiple appliances in the home. Domosys selected the CEBus® standard; as it is robust and open, CEBus is a rapidly emerging standard for power line carrier (PLC) in residential and commercial environments.

The SE-240 with a CEBus module offers several benefits. From the collection centre, the utility benefits from low-cost meter reading, outage detection and meter tampering. At the home or building level, benefits include the two-way communication link between the meter and any device with a CEBus compliant power line transceiver, allowing for time-of-use energy pricing, selective load shedding, appliance monitoring and preventive maintenance, customer profiling and energy management. 

Hunt Technologies, makers of the Turtle energy management system/AMR, has developed a prototype AMR single-phase transmitter module to interface with the SE-240. The prototype has all the functionality of existing Turtle transmitters, and utilises Hunt’s standard ultra-narrow bandwidth technology to transmit meter data to the utility substation over power lines.

The Hunt prototype module uses the available option slot EPRI has provided to read the pulses through an electrical interface. Hunt engineering leaders say this technology has distinct advantages because it removes opportunities for error in encoding consumption. The company has confirmed it will support EPRI and all meter manufacturers when they begin volume production of solid state meters.

Fig 3: Innovatics network provides full two-way
Innovatec’s network is a flexible, two-way communications system that provides communication between the meter and the utility, both on Wide Area Network and Local Area Network (see figure 3). Communications can be initiated in real time at any point on the network – head-end, gateway or meter. The network provides transmission of summarised usage information, not constant flow of data. It offers the ability to program remote devices over the network and has Java-enabled remote programming.

ISC Datacom is developing a module to provide AMR over CATV and broadband cable. The data systems are polled systems in which a computer speaks through a modem to field units one at a time. The 19.2 kbps data rate and the small amount of data being sent allow the poll times to be very rapid.

Nexsys is working closely with EPRI to incorporate its Home Area Network (HAN) board into the new meter. Nexsys is piloting the beta version of the HAN to several sites, and will soon begin to cost and reduce the size of the communication module to fit into the EPRI meter. The Nexsys system provides a full two-way communication network both inside and outside the premises. The EPRI meter houses the Nexsys home gateway board, which collects electric, water and gas consumption data, as well as receiving and processing emergency signals from smoke detectors and other peripheral devices. Data is routed to the appropriate host computer via a public WAN.

Williams Telemetry is developing a module that will operate as part of the information-gathering equipment, wireless networks and information-processing services that the company offers to energy distributors, merchants and users. The company bundles sensor/control devices with on-site network gateways that act as both local area servers and wide area clients communicating over a variety of nationwide and worldwide commercial networks.


The SE-240’s open architecture design is unique. A thorough examination of meters being offered for sale reveals no other open architecture, hot swap, residential electricity meter.

As a not-for-profit institute, EPRI is in a unique position to support the open architecture approach, and EPRI’s utility membership involvement in the development ensures market acceptance of the product. To encourage the participation of module vendors – and thereby establish the greatest degree of customer choice – EPRI has made the details of the interface for the SE-240 publicly available on the web at https://www.se-240.com.

This open architecture system provides market access for AMR vendors who might otherwise be denied it. New non-energy services that will use the AMR communications system, such as home security, can also be implemented through this open platform. Services that do not involve energy or an AMR system, such as a wireless home number module that provides emergency information to police, ambulance and fire personnel, can also be installed in the SE-240.


EPRI is also developing two other electronic meters. One of these is a version of the SE-240 that incorporates an internal 200 Amp disconnect switch (see figure 4). When interfaced with a two-way communications system, this new version will provide a remote disconnect capability. This meter can also be an integral part of a prepayment system.

Fig4: A new version of Epri's SE-240 meter features a 200 Amp disconnect switch

The other meter under development is for commercial and industrial applications. EPRI is preparing a specification for an open architecture interface for the meter, and this interface will be posted on the Internet for public viewing and comments shortly. Meter development to meet this specification will begin in early 2000. The meter will be developed as an open ‘front end’ with current and voltage sensors, A/D converter and processing. All data will be available to modules through a communications interface.


EPRI has conducted three surveys in the United States to determine what features utilities and their customers require. The first of these focused on the needs of 61 member utilities, selected to represent a wide range of company sizes across the U.S.A. This survey revealed a variety of specific plans for retail competition, including innovative rates, energy information and management services, and power quality services.

Results of the first survey were complemented by two surveys of customers – seeking, respectively, the viewpoint from corporate headquarters and from the field – to determine which of the value-added services might be of interest to customers. A survey of 21 national account customers focused on the advanced metering needs of major retail, supermarket, restaurant, health care, lodging and convenience store chains, as well as industrial customers and government agencies.