MPG-1 Advanced Settings (cont)
Bi-Directional Energy Flow (Signed Mode)
If you have energy flowing in both directions in the case of distributed energy resourses (solar, wind, etc), the MPG-1 can
provide both positive and negative pulses. This is known as the
Signed
mode, meaning that "kWh Delivered" (
from
the
utility
to
the customer) is positive or forward flow, and "kWh Received" (
from
the customer
to
the utility) is negative or
reverse flow.
The Pulse Value Setting (set by dip switches S1.1-S1.3) is the same for both positive and negative values.
To enter the functional or operational mode into the MPG-1, use the S and N commands. Press N <Enter> to set the
MPG-1 in the Normal mode. Press S <Enter> to set the MPG-1 in the Signed mode. The serial link to the MPG-1 will
return "Output Mode: Signed". To read what mode the MPG-1 is currently in, press R <Enter>. The serial link will return
the mode stored in the MPG-1. For example, "Output Mode: Normal" will be returned. Case does not matter.
Form C Signed mode - A positive energy value received from the meter is added to the positive Accumulated Energy
ReAER). Negative energy values received are ignored. Only Form C toggle pulses are generated on the KYZ
output for Positive energy flow. See Figure 3 below.
Form A Signed mode - A positive energy value received is added to the positive Accumulated Energy ReAER).
A negative energy value received is added to the negative Accumulated Energy Register(-AER). When either register
equals or exceeds the Pulse Value setting, a pulse of the corresponding sign is outputted on the correct line. Pulses in
this mode are Form A (2-wire) "Fixed" only. K-Y pulses are Positive pulses and K-Z pulses are negative pulses. They
share a common K terminal on the output. Set the pulse value with dip switches S1.1 thru S1.3. Set the pulse width
using dip switches S1.5 and S1.6. See Figure 4 below.
T1
Figure 4: 2-Wire (FORM A) FIXED Output Operation
K-Y Out
Open
Closed
Open
Closed
K-Z Out
KY closure time
In Signed mode, with a Form A output mode selected, the K-Y output pulse represents
positive (or kWh delivered) energy; K-Z output pulse represents negative (or kWh received)
energy.
(Positive)
(Negative)
Figure 3: 3-Wire (FORM C) TOGGLE Output Operation
K-Z Out
K-Y Out
Open
Open
Closed
Closed
Positive Energy Pulse Outputs Only
Positive and Negative Energy Pulse Outputs
In Signed mode, with a Form C output mode selected, the K-Y and K-Z output pulses
represent positive (or kWh delivered) energy; Negative (or kWh received) energy is ignored.
Positive Flow
Positive Flow
Negative Flow
Positive Flow
Positive Flow
Negative Flow
