Manual

Chapter 2 Operating the EM920
Communicating with the EM920
28 EM920 Power Quality and Revenue Meter
You can check the Ethernet port MAC address and present IP
address setting via the Device Info display (see Device Info
Display in Chapter 3).
See Setting Up the Ethernet
in Chapter 5 on how to configure
your Ethernet port.
The meter provides two TCP servers configured for the
Modbus/TCP (port 502) and DNP3.0/TCP (port 20000)
protocols.
The TCP servers support 5 simultaneous Internet connections
with client applications. Connection through the Ethernet port
does not require device identification. The meter responds to
any device address and returns the received address in the
response message.
The meter also provides three TCP clients:
• SNTP client for periodic synchronization of the meter
clock with a publicly available SNTP server (see
Setting-Up SNTP Client
)
• eXpertPower
TM
client for communications with the
proprietary eXpertPower
TM
server (see Setting-Up
eXpertPower Client)
• TCP notification client that can establish connections
with a remote Modbus/TCP server and send
notification messages either on events, or periodically
on a time basis (see Setting-Up TCP Notification Client)
GSM/GPRS Wireless Communication
An optional GSM/GPRS modem can be provided with the
EM920 for wireless communications via a cellular GPRS
network. It is identified by the EM920 as port COM2.
The module has two indication LEDs that operate as follows:
LED Color Status Description
LINK Green Flashes/Lights Flashes while the modem is registering
on the GPRS network and is lit up after
the meter has logged on the network
RSSI Yellow Flashes Received signal strength indicator -
shows the quality of the received signal
as follows:
Flashes once a second – good quality –
the signal strength is above -109 dBm.
Flashes twice a second – bad quality –
the signal strength is less than -109
dBm.
Shut off – the signal strength is not
known or not detected.
See Setting-Up Dial-Up GPRS Network in Chapter 5 on how to
configure the GPRS modem and how to check a dynamically
assigned IP address the meter got from the GPRS network.
You can also check the meter IP address and the quality of
the received signal via the Device Info display (see Device
Info Display in Chapter 3).
The EM920 eXpertPower
TM
client and TCP notification client
can establish connections with remote servers via a GPRS