Obvius A7801 - Manual (Page 13)

Pulse Input
Click the “Configure Point” button to the right of the pulse input consumption point as shown in the previous image.
In this configuration page, you may set the name of the pulse input. This will allow you to give the data point a name that
represents the function of the meter. “Main Building Power” for example.
The multiplier is used to convert the pulses to engineering unit data. For example, if your meter provides one pulse per
0.01KWH, then a multiplier of 0.01 is required. Each model of power meter is different and has a different multiplier.
You must obtain the correct pulse multiplier from the meter manufacturer prior to configuring the AcquiLite.
Some power meters have an option to configure the multiplier. Options often include 1, 0.1, 0.01, kwh per pulse. The best
method to configure the pulse is to select the smallest multiplier available, considering the maximum load and pulse rate. To
calculate the pulse rate,use the following formula:
pulses per second = KW ÷ 3600 ÷ multiplier.
For example, if you have a meter on a 100KW load and a multiplier of 0.01kwh/p
100KW ÷ 3600 ÷ 0.01 = 2.7 pulses per second.
The AcquiLite can count pulses at speeds of 10 pulses per second, however it is best to scale the pulse multiplier to that one
pulse per second is the maximum rate. Counting pulses at a higher rate than 10 pulses per second will cause the AcquiLite
to miss pulses.
The AcquiLite can count a maximum of 2^32 (4.295 billion) pulses. At a rate of 5 pulses per second, the AcquiLite counter
will roll over in approximately 27 years. Needless to say, rollover should never be an issue.
The KYZ option, when checked, will cause the AcquiLite to count both the leading and trailing edge of the pulse. By
default, this option is unchecked, and only contact closures are counted. (not contact openings). If you have a true KYZ
meter, each opening is counted as a pulse, and each closure is another pulse. For further details on KYZ meters, please
review the technote on the topic at
www.obvius.com .
The Units field is used to configure the engineering units for this input. e.g. KWH, Gallons, Cubic Feet, etc.
Pulse Input Rate configuration
A second “Config Point” button is present next to the pulse rate data point. This option will allow you to configure the unit
of measure for the Rate point, as it pertains to the consumption point. For most units of measure, the rate is automatically
calculated and this option will not be present. For example, if the consumption is measured in KWH, the rate will be KW.
To configure this option, click the Config Point button. You may select a rate “per minute” or “per hour” to correctly scale
the measure. Thus, if your consumption units are “gallons”, the rate will be “gallons per minute”.
Page 13 A7801 AcquiLite – Data Acquisition Server