SATEC EM720 Operation Manual - Manual (Page 29)

Chapter 2 Operating the EM720
Auxiliary AC/DC Backup Power Supplies
EM720 Power Quality and Revenue Meter 29
USB Communications
An optional Ethernet/USB module provides a full speed 12-
Mbit USB 1.1 port for local communications with the support
PAS software. The USB module can be installed in the
expansion slot 1 or 2.
USB communications does not require any settings. Just
connect your PC to the EM720 USB port using the supplied
USB cable with a mini-USB connector and install the USB
driver provided on the CD with your meter (see
Installing the
USB Driver in Chapter 4).
To prevent potential differences between the PC USB
port and the EM720 USB device port, it is
recommended to use a galvanically isolated USB
adaptor before connecting the EM720 USB port to a
PC, or to use a battery powered PC.
Auxiliary AC/DC Backup Power Supplies
An auxiliary 24VDC or 85-265VAC/90-290VDC backup power
supply module can be provided for powering the meter from
an external power source, like a station battery, in the event
of power outages. It can be used either as a replacement for
the internal auxiliary backup battery, or as an additional
backup source for maintaining continuous uninterrupted
operation of the meter.
The module can be installed into any expansion slot.
See the EM720 Installation Manual for the power supply
ratings and connection diagrams.
The 24VDC supply module has two indication LEDs that
operate as follows:
LED Color Status Description
VIN Green Lights External DC voltage is applied to the input
terminals
VOUT Green Lights/
Shut off
Lights- the module supplies the power to
the meter while the AC voltages are not
available on any reason
Shut off – the module is in standby while
the meter is powered from the AC inputs
The AC/DC supply module is provided with a green LED that
lights when the external voltage is applied to the input
terminals.