sames

SA2002D

6/10

http://www.sames.co.za

Direction input (DIRI)

Energy Direction Selection

The DIRI input pin allows the representation of the measured

energy to be selected. The representation can be of any three

types:

Pulses are generated on the output if the energy flow is

positive. Any negative energy (reverse energy) flow is

disregarded.

Pulses are generated on the output if the energy flow is

negative. Any positive energy flow is disregarded. Negative

energy flow is defined as the condition where the voltage

sense input and current sense input are out of phase (greater

than 90 degrees).

Pulses are generated on the output if the energy flow is

positive or negative. The energy direction may be ascertained

by monitoring the DIRO pin.

Positive Energy

Negative Energy

Bi-direct

OUTPUT SIGNALS

Motor Pulse Output (MOP, MON)

These outputs can be used to drive an electromechanical

counter directly at 100 (200) impulses per kWh. See table 1.

DIRI

Direction

1

0

DIRO

Positive

Negative

Bi-direct

Fast Calibration (FAST)

The SA2002D may be put in a fast calibration mode by setting

FAST to V . In this mode the pulse rate is 1252Hz on the LED

output at rated conditions.

DD

Figure 5: Motor output MON and MOP

VDD

VDD

VSS

VSS

MON

MOP

t

m

t

m

t

m

DR-01559

t = 230ms

m

LED Output (LED)

The LED pulse output follows the average power consumption

measured and is intended for calibration purposes. The pulse

rate is dependant on the settings of pins R0, R1 and R2 (see

rated conditions select). The LED output is active low. The LED

waveform is shown below:

Figure 6: LED pulse output

LED

t

LED

DR-01332

VDD

VSS

An integrated anti-creep function prevents any output pulses if

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

current.

The SA2002D provides information about the energy flow

direction on pin DIRO. A logic 0 on pin DIRO indicates reverse

energy flow. Reverse energy flow is defined as the condition

where the voltage sense input and current sense input are out

of phase (90..270 degrees).

Positive energy flow, when voltage sense and current sense

input are in phase, is indicated on pin DIRO as a logic 1.

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

reverse energy.

Direction Indication (DIRO)

T

= 10ms

LED