78M6612-IMSLASHFSLASHP datasheet(87/111 Pages) TERIDIAN

87 / 111 page

DS_6612_001

78M6612 Data Sheet

Rev. 1.2

4.4.7.3 Other Measurement Parameters

MAINEDGE_X is useful for implementing a real-time clock based on the input AC signal. MAINEDGE_X is

the number of half-cycles accounted for in the last accumulated interval for the AC signal.

TEMP_RAW may be used by the MPU to monitor chip temperature or to implement temperature

compensation.

Address

Name

Default

Description

0x73

MAINEDGE_X

N/A

The number of zero crossings of the selected voltage in

the previous accumulation interval. Zero crossings are

either direction and are debounced.

0x71

TEMP_RAW_X

N/A

Filtered, unscaled reading from the temperature sensor.

0x19

GAIN_ADJ

16384

Scales all voltage and current inputs. 16384 provides unity

gain.

0x11

SAG_THR

313000

The threshold for sag warnings. The default value is

equivalent to 80V RMS if VMAX = 600V. The LSB value is

VMAX * 4.255*10

-7V (peak).

GAIN_ADJ is a scaling factor for measurements based on the temperature. GAIN_ADJ is controlled by

the MPU for temperature compensation.

4.4.7.4 Pulse Generation

Address

Name

Default

Description

0x0F

WRATE

486

Kh = VMAX *IMAX * 47.1132 / (WRATE * NACC * X)

Wh/pulse. The default value results in a Kh of 3.2 Wh/pulse

when 2520 samples are taken in each accumulation interval

(and VMAX=600, IMAX = 52, X = 6).

The maximum value for WRATE is 2

WRATE controls the number of pulses that are generated per measured Wh and VARh quantities. The

lower WRATE is the slower the pulse rate for measured energy quantity. The measurement constant Kh

is derived from WRATE as the amount of energy measured for each pulse. That is, if Kh = 1Wh/pulse, a

power applied to the measurement unit of 120 V and 30 A results in one pulse per second. If the load is

240 V at 150 A, ten pulses per second will be generated.

The maximum pulse rate is 7.5 kHz.

The maximum time jitter is 67 µs and is independent of the number of pulses measured. Thus, if the

pulse generator is monitored for 1 second, the peak jitter is 67 ppm. After 10 seconds, the peak jitter is

6.7 ppm.

The average jitter is always zero. If it is attempted to drive either pulse generator faster than its maximum

rate, it will simply output at its maximum rate without exhibiting any rollover characteristics. The actual

pulse rate, using WSUM as an example, is:

– 1.

WSUM

WRATE

RATE

⋅

where FS = sampling frequency (2520.6 Hz), X = Pulse speed factor.

78M6612-IM/F/P Datasheet(PDF) 87 Page - Teridian Semiconductor Corporation

78M6612-IM/F/P Datasheet(HTML) 87 Page - Teridian Semiconductor Corporation

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