sames

SA2102D

10/16

http://www.sames.co.za

POWER

Time

Voltage

Instantaneous Power

0V

67 - 70 µS

67 - 70 µS

Pulse stability

disabled

Pulse stability

enabled

Current

LED Output (LED)

The LED output pin provides a pulse output with a frequency

proportional to the average energy when in STANDARD mode

and

the instantaneous energy when in FAST mode. This

output is primarily used for calibration purposes. The Rated

Conditions Select pins (R0, R1, R2) allow different frequencies

to be selected. The LED output is active low. Figure 8 shows

the LED waveform when in STANDARD mode.

Vss

Vdd

t1

t2

OUTPUT SIGNALS

Motor pulse output (MOP, MON)

The MOP and MON pins are complimentary outputs with a

frequency proportional to the average power consumption

measured. These outputs can be used to either directly drive a

stepper motor counter or an electro mechanical impulse

counter. The Rated Conditions Select pins (R0, R1, R2) allows

the selection of different output frequencies corresponding to

different Meter Constants. Figure 7 indicates the timing of

these signals.

3600

IxV

1000

()

Frequency (pulses per second) = P/kWh

P/kWh = frequency x

3600

IxV

1000

()

t1 = t2 = t3 = 213ms

t4 is proportional to the average power and can be calculated

using Equation 2 and the Motor Output Constants in Table 2.

Figure 7: Motor output MON and MOP

VDD

VDD

VSS

VSS

MON

MOP

t3

t1

t2

t4

t1 = 90ms

t2 is proportional to the average power and can be calculated

using Equation 1 along with the appropriate LED Output

Constant in Table 1.

Figure 8: LED pulse output in STANDARD mode

In FAST mode the LED pulse output is set at a high frequency

of 1160Hz at I

and V

This mode is useful for fast

calibration and can be used to interface to a micro-controller.

Figure 9 indicates the LED output signal in FAST mode.

MAX

NOM.

Figure 9: LED pulse output in fast mode

To convert pulses per kilowatt-hour to frequency (in Hz ) or vice

versa the following equations can be used:

where:

P/kWh = LED or MON/MOP pulse constant

I = current in amperes

V = voltage (normally V

)

The direction energy flow may be ascertained by monitoring

the DIRO pin. A logic 0 on this pin indicates negative energy

flow. Positive energy flow, is indicated on pin DIRO as a logic 1.

The DIRO pin may be used to drive a LED.

NOM

Direction Indicator Output (DIRO)