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sames

sames

SA2007P

http://www.sames.co.za

INPUT SIGNALS

VREF

A bias resistor of 24kW set optimum bias and reference

conditions on chip. Calibration of the SA2007P should be done

as described in the Device Configuration section.

Serial Data (SDA)

The SDA pin connects directly to the SDA pin of an external

EEPROM. The pin is used to transfer data between the

EEPROM to the SA2007P. An external pull up resistor in not

needed.

Serial Clock (SCL)

The SCL pin connects directly to the SCL pin of an external

EEPROM. The SCL output is used to strobe data at a rate of

50kHz out of the EEPROM. An external pull up resistor in not

needed.

Configuration Reload (RLOAD)

A falling edge on the RLOAD pin, will trigger a register update

from the external EEPROM. This feature may be used during

calibration to load updated register data in the SA2007P. For

normal operation of the SA2007P the RLOAD pin may be left

floating.

OUTPUT SIGNALS

Motor output (MOP, MON)

The motor pulse width is programmable for 71ms and 142ms.

The MON pulse will follow the MOP pulse within the selected

pulse width time. This prevents that the motor armature is in

the wrong position after a power failure. Both MOP and MON

outputs are active high. One energy pulse is represented by a

MOP pulse followed by a MON pulse. The motor drive wave

forms are shown in figure 4.

LED output (LED)

Three options for the LED output pulse rate are available, 6400

and 3200 pulses per kWh, as well as a pulse rate of 1252

pulses per second at rated conditions. At 1252 pulse per

second t

is 71µs, for the other options t

is 10ms. The LED

LED

LED

output is active low as in figure 5.

An integrated anti-creep function prevents any output pulses if

the measured power is less than 0.02% of the meters rated

current.

Figure 4: Motor drive on MON and MOP pins

Figure 5: LED pulse output

Selected Input Indicator (SEL1)

The SA2007P continuously compares the power

consumptions on current channel 1 inputs and current channel

2 inputs. The larger of the two measurements is used for

metering. The SEL1 output pin indicates which channel is

currently being used for the pulse output.

Signal

Output

Value

Description

SEL 1

0

1

Channel 1 selected (IIN1/IIP1)

Channel 2 selected (IIN2/IIP2)

Switching between channels will not be faster than once per

second in case both channels are balanced.

Earth Loop Tamper Indication (ELT)

In case the power measurements from both current channels

differ by more than 12.5%, (indicating a earth loop tamper

condition), the ELT output is set to zero. The SA2007P

continues to generate output pulses from the larger of the two

measured powers in this condition. The ELT output is active low.

Direction Indication (DIRO)

The SA2007P provides information about the energy flow

direction of both current channels on pin DIRO .

A logic 1 on pin DIRO indicates reverse energy flow of both

current channels. Reverse energy flow is defined as the

condition where the voltage sense input and current sense

input are out of phase (greater than 90 degrees). Positive

energy flow, when voltage sense and both current sense input

are in phase, is indicated on pin DIRO as a logic 0.

The DIRO output will toggle between 1 and 0 a rate of 1Hz in

case one of the current channels measure positive energy and

the other negative energy. The condition may accure with a

improper installed or tampered meter.

The DIRO pin may be used to drive a LED in order to indicate

reverse energy.

VDD

VDD

VSS

VSS

MON

MOP

t

m

t

m

t

m

DR-01559

LED

t

LED

DR-01332

VDD

VSS

Signal

Output

Value

Description

DIRO

1

0

Reverse energy flow

Forward energy flow

1Hz

Out of phase current channels

PRELIMINARY