SA4101A South African Micro-Electronic Systems, SA4101A Datasheet - Page 10

• Manufacturer Part Number: SA4101A
• Description: Single Phase KWH Metering ic With Pulse Output
• Manufacturer: South African Micro-Electronic Systems

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.
MOP
MON
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.
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.
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.
http://www.sames.co.za
SA4101A
Vss
Vdd
Figure 8: LED pulse output in STANDARD mode
VDD
VSS
VDD
VSS
Figure 7: Motor output MON and MOP
t1
t1
t2
t4
t3
t2
10/16
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
Direction Indicator Output (DIRO)
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.
In FAST mode the LED pulse output is set at a high frequency
of 1160Hz at I
calibration and can be used to interface to a micro-controller.
Figure 9 indicates the LED output signal in FAST mode.
Pulse stability
enabled
Pulse stability
disabled
Frequency (pulses per second) = P/kWh
P/kWh = frequency x
POWER
0V
Figure 9: LED pulse output in fast mode
Voltage
MAX
and V
Current
NOM
)
NOM.
Instantaneous Power
(
3600
1000
I x V
This mode is useful for fast
67 - 70 µS
67 - 70 µS
)
sames
sames
(
3600
1000
I x V
Time
)