APPENDIX A: APPLICATION NOTES
PULSE TOTALIZER APPLICATION
PQM POWER QUALITY METER – INSTRUCTION MANUAL
A–25
Configuring the PQM to Totalize Energy From Multiple Metering Locations:
FIGURE A–4: Multiple Metering Locations
The diagram above shows an example of a PQM being used to totalize the energy from 4
other PQMs. PQMs 1 through 4 have each of their respective AUX1 relays configured for
Pulse Output functionality (refer to the Pulse Output PQM Application note for details, or
the PQM manual). The Switch Common output from PQM#4 is fed to the common contact
of the AUX1 relays on PQMs 1 through 4. The N/O contact of AUX1 for PQMs 1 through 4
will operate based upon the setup as described in the Pulse Output functionality section of
the PQM manual. The Totalized Pulse Input register of PQM#4 can be set to sum the counts
from Switch Inputs 1 through 4, thus giving a total energy representation for the 4
metering locations. The count value for each Pulse Input on PQM#4 can be set to match
the Pulse Output Interval as programmed on each PQM. For example, if PQM#1 had a
Pulse Output Interval = 100 kWhr, and PQM#2 had a Pulse Output Interval = 10 kWhr, then
Pulse Input 1 on PQM#4 would have the Pulse Input Value set for 100 and Pulse Input 2 on
PQM#4 would have the Pulse Input Value set for 10.
Various operating parameters with regard to the PQM Switch Inputs must be taken into
account. The PQM Switch Inputs require a minimum 100 ms operation time to be detected.
Therefore the Pulse Output Width should be equal to or greater than 100 ms. The duration
of the contact operation can be indefinite. The internal Switch Input circuit of the PQM is
itself switched on and off at the times when the PQM is reading the status of the Switch
Inputs. Monitoring the input to one of the PQM Switch Inputs will reveal a pulsed 24 V DC
waveform, not a constant signal. Standard wiring practice should be adhered to when
making connections to the PQM Switch Inputs, i.e. avoiding long runs of cable along
current carrying conductors or any other source of EMI. An induced voltage on the Switch
Input can cause malfunction of the Switch Input.
M
L
L
PQM
#1
PQM
#2
PQM
#3
F1
F2
F3
M
F4
AUX1
AUX1
AUX1
COM
COM
COM
41
41
41
42
42
42
N/O
N/O
N/O
AUX1
COM
41
42
N/O
PQM
#4
+24VDC
SW1
SW2
SW3
SW4
33 32 31 30 29
Содержание Multilin PQM
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