Pulse Scaling

Solution

By default, the pulse value is 1Wh / pulse, but you need to include the CT multiplier.

The CT multiplier is typically calculated as the full scale of the meter divided by 5.

For example:
WattsOn-1100-MSCT1-200A , the pulse value is 40 Wh/pulse
WattsOn-1100-MSCT3-800A , the pulse value is 160 Wh/pulse

For a WattsOn-1100-5A, used with 100:5A CTs, the pulse value is 20Wh/pulse

Please note that this is assuming the value is not changed from factory defaults. This is also always included on the calibration sheets shipped with the meters.

Note: the Pulse value can also be software adjusted using the Pulse Value Register.  This register is described on page 17 of the manual (http://www.elkor.net/pdfs/WattsOn_Manual.pdf)

Pulse Value Register:
Configures the number of Wh / VARh required to generate one pulse on the Wh or VARh pulse outputs. ie: if this register is set to 10, ten Wh must accumulate before a pulse is triggered. In this case the pulse value would be 10 Wh / VARh per "click". As with the current and power registers, the proper PT/CT ratio must be applied to the pulse outputs for proper engineering units. Ie: if the meter is designed to output 1 pulse per 10Wh, and the CT ratio is 800:5, the value of one click becomes 10 * 80 0/5 = 1600 Wh (1.6kWh)

Setting the Pulse Value Register to a value of “0” sets the output pulse value to 0.1 Wh/VARh ( x CT/PT ratios) per pulse. Ie: with a CT ratio of 800:5, the pulse is 16 Wh/pulse.  At settings of “1” or higher (>=1Wh/pulse), the pulse output is a 100ms contact closure. At a setting of “0” (0.1Wh/pulse) the pulse duration is 50ms with a minimum 50ms interval between pulses. This may have a bearing on PLC/DDC systems, as some are incapable of detecting short pulse durations.

Article details

Article ID: 2

Category: WattsOn

Date added: 2011-05-10 15:13:24

Views: 913

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