Mitsubishi Electric MELSEC iQ-R - Page 284

282
APPX
Appendix 6 BACnet Detail Setting List
When a PulseDirectInput is 0
Set '0' to a PulseDirectInput when adding the amount of electric energy.
In a PresentValue property, the value calculated with the following formula is stored.
• PresentValue property= Previous PresentValue property value + Calculation result of Prescale
*1
*1 Calculation result of Prescale = Differential value of pulse counter/ModuloDivide*Multiplier
Page 282 Differential value of a pulse counter
Page 283 Setting method of the values of a Multiplier and ModuloDivide
Ex.
When '1' is set to "ModuloDivide" and '10' is set to "Multiplier", 10 is added to the PresentValue property value every time the
number of pulses increases.
■ Differential value of a pulse counter
The differential value of a pulse counter
*1
can be calculated from the value of a pulse input in the buffer memory
*2
(b15: reset
flag, b14 to b0: CTA).
*1 For an Accumulator object, the differential value of a pulse counter is stored to a Pulse_Rate property within the time period specified to
a Limit_Monitoring_Interval property. (Page 268 Properties of an Accumulator object)
*2 For pulse input in the buffer memory, refer to the following sections.
Accumulator objectPage 79 Pulse input
Keiryo objectPage 83 Pulse input
When resetting a pulse counter using a program, write '8000h' (reset flag: 1, CTA: 0) to the pulse input in the buffer memory.
After the value is written, do not change the value of the reset flag (1) until the CTA reaches '7FFFh'. When the CTA reached
'7FFFh', the reset flag should be changed to '0' to initialize the CTA.
Precautions
• The previous CTA value is preset to '0' at the startup of a BACnet module.
This should be taken into consideration when creating a program.
Present reset
flag
Previous reset
flag
Description Differential value of a pulse
counter
1 0 Since the counter value was initialized, the differential value is a present
CTA.
Present CTA
1 • Previous CTA > Present CTA
Since the CTA was reset again before it became '7FFFh' after the CTA
was reset, the differential value is a present CTA.
Present CTA
• Previous CTA  Present CTA Present CTA - Previous CTA
0 0 • Previous CTA > Present CTA
Since the CTA reached '7FFFh' and was counted from '0' again, the value
of a present CTA is smaller than that of a previous CTA.
8000h - Previous CTA + Present CTA
• Previous CTA  Present CTA Present CTA - Previous CTA
1 Since the CTA reached '7FFFh', reset to 0, and counted up, the reset flag
became '0'.
8000h - Previous CTA + Present CTA