Schneider Electric 4000 manual Input Pulse Demand Metering

Chapter 4—Metering Capabilities	63230-300-212
Demand Readings	April 2001
Input Pulse Demand Metering	The circuit monitor has ten input pulse metering channels. The channels
	count pulses received from one or more digital inputs assigned to that
	channel. Each channel requires a consumption pulse weight, consumption
	scale factor, demand pulse weight, and demand scale factor. The
	consumption pulse weight is the number of watt-hours or kilowatt-hours per
	pulse. The consumption scale factor is a factor of 10 multiplier that
	determines the format of the value. For example, if each incoming pulse
	represents 125 Wh, and you want consumption data in watt-hours, the
	consumption pulse weight is 125 and the consumption scale factor is zero.
	The resulting calculation is 125 x 100, which equals 125 watt-hours per pulse.
	If you want the consumption data in kilowatt-hours, the calculation is 125 x
	10-3, which equals 0.125 kilowatt-hours per pulse.
	Time must be taken into account for demand data so you begin by calculating
	demand pulse weight using the following formula:

watts =	watt-hours x	3600 seconds x	pulse
	per pulse	per hour	per second

If each incoming pulse represents 125 Wh, using the formula above you get 450,000 watts. If you want demand data in watts, the demand pulse weight is 450 and the demand scale factor is three. The calculation is 450 x 103, which equals 450,000 watts. If you want the demand data in kilowatts, the calculation is 450 x 100, which equals 450 kilowatts.

The circuit monitor counts each input transition as a pulse. Therefore, for an input transition of OFF-to-ON and ON-to-OFF will be counted as two pulses. For each channel, the circuit monitor maintains the following information:

•Total consumption

•Last completed interval demand—calculated demand for the last completed interval.

•Partial interval demand—demand calculation up to the present point during the interval.

•Peak demand—highest demand value since the last reset of the input pulse demand. The date and time of the peak demand is also saved.

•Minimum demand—lowest demand value since the last reset of the input pulse demand. The date and time of the minimum demand is also saved.

For example, you can use channels to verify utility charges. In Figure 4–6,Channel 1 is adding demand from two utility feeders to track total consumption and demand for the building. This information could be viewed in SMS and compared against the utility charges.

To use the channels feature, first set up the digital inputs from the display or from SMS. See “Setting Up I/Os” on page 23 in Chapter 3—Operationfor instructions. Then using SMS, you must set the I/O operating mode to Normal and set up the channels. The demand method and interval that you select applies to all channels. See the SMS online help for instructions on device set up of the CM4000 Circuit Monitor.

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