MPG-2ES Wireless Meter Pulse Generator
6.0 Operation
6.1
Communication LEDs
Upon power-up, the yellow COM LED should light indicating that the Zigbee dongle is enumerated, correctly initialized and
communicating with the MPG-2ES's processor. Within approximately 45 - 60 seconds, the green COM LED will blink each
time a valid transmission is received from the meter. As long as valid transmissions are received by the RAVEn dongle and
successfully relayed by the MPG-2ES's processor, the green COM LED will blink about once every 8-9 seconds. If the
green COM LED does not blink, that is an indication that the data transmissions from the meter are not being received, may
be corrupted, or in some manner are not valid transmissions. If the green COM LED has been blinking reliably for some
time, then stops for a while and then restarts again, this indicates that transmissions are intermittent and sporadic, or
generally means there is a problem in the dongle's ability to receive data reliably from the meter. To correct this, move the
MPG-2ES closer to the meter if possible and eliminate any metalic obstructions between the meter and the MPG-2ES. For
the longest distances you must have line-of-sight.
6.2
Pulse Outputs
Output can be configured to be in the
Toggle
(Form C) mode or the
Fixed
(Form A) mode. Generally speaking, the Form C
mode can be used with either 2-Wire or 3-Wire pulse receiving devices, while the Form A mode uses only a 2-Wire interface
to the downstream (receiving) pulse device. The choice would depend on the pulse format that is most compatible with the
application of the receiving device. The MPG-2ES uses only two output wires so the HARDWARE is FORM A only.
However, it can be operated in either the Toggle or Fixed mode.
If the pulse output value is too high and pulses are too slow, then select a lower pulse value using the programming port and
a terminal program (See Page 6).
If pulses are being generated too rapidly, select a higher pulse output value. The maximum number of pulses per second is
approximately 10, which means that the output's open and closed times are about 50 mS each in Toggle mode. If the
calculation by the MPG-2ES's processor for pulse output timing exceeds 15 pulses per second, the MPG-2ES will light the
red COM LED, indicating an overflow error, and that the pulse value is too small. The LED is "latched" on so that the next
time you look at it this red LED will be lit, and you will have an indication that an error has occurred. The operation of the
MPG-2ES will continue even though some pulses were lost. In this way, you can quickly determine if a pulse output value is
too small, and thus pulses too fast at a high demand. However, in the optimum application, pulses would not exceed more
than one pulse every 2 seconds, with a 1 pulse per second maximum. This allows a very even and "normal" pulse rate that
resembles an actual KYZ pulse output from the meter as closely as possible.
The MPG-2ES will spread out the pulses over the next 7-second period if a high enough watt-hour value is received in a
transmission to require that more than one pulse is generated. For example, suppose you have the output pulse value of 10
Wh selected. The next 8-second transmission indicates 24 Wh have been used. Since 24 watt-hours exceeds the 10 watt-
hour setting, two pulses must be generated. The first 10 Wh pulse will be generated immediately. About three seconds
later the second 10 Wh pulse will be generated. The remainder of four watt-hours stays in the accumulated energy register
(AER) awaiting the next transmission and the energy value of that transmission will be added to the contents of the AER.
Another example: Assume 25 Wh/p output pulse value. Let's say the next transmission is for 130 watt-hours. 130 is greater
than 25, so 5 pulses will need to be generated over the next 7 seconds, approximately one each 1.4 seconds (7 seconds / 5
= 1.4 seconds). The remainder of 5 Wh will stay in the AER awaiting the next transmission. Some trial and error may have
to be done for any particular building since pulse rates will change depending on maximum load. The larger you can make
the pulse value the more regular the output pulses from the MPG-2ES will be.
5.3
Overranging the Output
As mentioned above, if there are too many pulses calculated to be generated in a 7-second interval than the MPG-2ES can
generate given the timing constraints, the MPG-2ES will light the red COM LED. In this situation, simply increase the Pulse
Output Value using the programming port, and cycle power to the MPG-2ES to reset the red COM LED. This is intended to
notify the user that a higher pulse value is needed. As load is added to a building over time, there is some likelihood that
this will occur so be sure to consider this if/when you add load to the building. If an error condition occurs, set the pulse
value to a higher, for example double the current value. Remember to change the pulse constant of your receiving device
as well, since pulses will now be worth a higher watt-hour value. Cycle power to the MPG-2ES to reset the red COM LED
after increasing the pulse value.
