Rockwell Automation Energy Management Accelerator Toolkit Quick Start - Manual (Page 431)

Rockwell Automation Publication IASIMP-QS016C-EN-P - October 2014 431
Appendix
C
Energy Electric Add-On Instructions
This appendix describes the behavior of the Energy_Electric_Digital, Energy_Electric_Analog, and
Energy_Electric_PM_Status Add-On Instructions. It is provided to help you understand the output values and calculations
methods. It also provides information you need to adjust consumption rollover values, and interval timer presets. Tag names
for end of demand intervals from a utility meter or central controller are also included.
The Add-On Instructions perform four functions.
• Calculate the total electric consumption, kWh, for the metered input. This value is stored is the in Add-On
Instruction output, Val_Total_kWh.
• Calculate the demand for the metered input over a user-defined interval.
• Provide the Equipment Status Faceplate, total Val_Total_kWh, Val_Demand_Electric, and
Demand_Interval_PLC_Timer.ACC values with the predefined device status information.
• Provide the Alarm History Faceplate information needed to display predefined alarm messages based on the device
status.
CompactLogix Digital Input Logic
The following logic is included in the Energy_Electric_Digital Add-On Instructions to calculate the total kWh electric
consumption from a CompactLogix digital input.
The Inp_Pulse tag initiates a total kWh computation. Every time a pulse is triggered, the logic adds the value of the
Set_Meter_Pulse_Factor tag to the Val_Total_kWh (total consumption) tag. The Inp_Pulse tag is assigned to a
CompactLogix digital input and the Set_Meter_Pulse_Factor is entered when the Add-On Instruction is added to your
program.
When the total kWh value reaches 10 million, the rollover rung resets the Val_Total_kWh value.