Satec expertmeter EM720 Operation Manual page 72

Chapter 5 Configuring the EM720
72
volts, and THD < 10% for currents. In networks with
high harmonics, the following method is preferable.
3. When the non-active power calculation mode is
selected, active power is measured directly, apparent
power is taken as product S = V x I, where V and I are
the RMS volts and amps, and reactive power (called
non-active power) is calculated as:
2 2
N = S − P
Tariff Control
The EM720 provides three options for switching tariff rates:
• automatic via a programmable TOU calendar schedule
(see Configuring the Daily Tariff Schedule
information on configuring tariff change points)
• external via communications by writing a tariff number
to the meter tariff register (see the EM720 Modbus
Reference Guide for information on the active tariff
register location)
• external via digital inputs by providing a tariff code on
the meter tariff inputs
If a digital input option is selected, you can use 1 to 3
consequent digital inputs as tariff inputs. The following table
shows the number of inputs required depending on the
maximum number of used tariff rates.
Number of tariffs
The following table shows code combinations that should be
provided on the tariff inputs to indicate an active tariff rate.
Tariff rate
number
1
2
3
4
5
6
7
8
EM720 Power Quality and Revenue Meter
General Meter Setup
Number of tariff inputs
2
3
4
5
6
7
8
Tariff code
Tariff Tariff
input 1 input 2
Open Open
Closed Open
Open Closed
Closed Closed
Open Open
Closed Open
Open Closed
Closed Closed
for
1
2
2
3
3
3
3
Tariff
input 3
Open
Open
Open
Open
Closed
Closed
Closed
Closed