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User Guide SL7000 IEC7
64
Note:
Earlier versions of the meter have these port assignments reversed.
Modem power supply
The RJ45 connectors can provide a DC supply voltage (VMDM) suitable for powering an external modem.
10VDC -10/+20% at 300mA (3W max).
Modem powering restriction
The meter is able to start if at least one phase or the APS is present. All functions are available if :
-
APS is present and APS>100V
-
or if at least 2 phases are present.
If APS is not present, and meter is powered on 1 phase only, the modem power supply is inhibited.
If meter is powered with APS and APS <100VDC or APS<100VAC, the modem power supply is inhibited.
If meter is powered with 2 phases (modem power is so available) and one phase is lost, then modem power
supply is cut immediately.
If meter is powered with more than 2 phases or switch to the APS, the modem power supply management is then
authorized.
7.3.
Real-time data
The meter can be configured to transmit real-time read-only data in accordance with IEC62056-21 through one of
the serial communication ports. This allows an external device or a SCADA (Supervisory Control And Data
Acquisition) system to collect and process the pre-defined metering data as and when it is required.
7.4.
Modem connection
The meter supports HAYES™ command-set compatible modems that conform to the following CCITT protocol
standards:
Standard
Effective transfer speed
V.22
1200bps
V.22bis
2400bps
V.32
9600bps
V.32bis
14400bps
The meter can perform bi-directional communication with the attached modem to initialise and control its
functions. The modem would normally operate in auto-answer mode.
The meter has several modem-management modes:
•
Device dedicated line on utility port
A modem connected to the port is fully managed and controlled by the meter. In order to improve modem
communication the meter will periodically switch off the modem power supply signal (VMDM) to reinitialise
the modem.
•
Direct line no modem control
Even if a modem is connected to the port, it is not managed by the meter. Always select this mode when
connecting meters together on a communication bus using RS485 daisy-chaining techniques.
•
Power supply on
The modem power supply signal (VMDM) is permanently enabled. Any modem connected to the port will not
be managed but will be powered by the meter.