SINGLE PHASE POWER/ENERGY METERING MODULE

PULSE OUTPUT

sames

PM9102AP

SA9102 / SA9602 APPLICATION NOTE

4308

PDS038-SA9102-001

REV.C

06-08-98

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FEATURES

Performs both power and energy
measurement

Meets the accuracy requirements for
Class 1 AC Watt hour meters

Protected against ESD

Total power consumption rating below
500mW (excluding current sensing)

Uses a shunt resistor for current sensing

Operates over a wide temperature range

DESCRIPTION
The SAMES single phase power/energy metering module, the PM9102AP, provides two
pulse rate output options, the frequency of which are proportional to the active power
consumption.

Energy consumption is determined by the power measurement being integrated over
time.

The method of calculation takes the power factor into account.

The output of this innovative universal power/energy metering circuit is ideally suited for
energy calculations in applications using a µ-controller or mechanical counter.

The application utilises the SAMES SA9102CP, SA9102FP, SA9102HP, SA9602EP
(DIP-20), SA9602HP (DIP-20) or SA9602MP power metering integrated circuits for
power measurement.

As a safety measure, this application shows the current sensor connected to the neutral
line. In practice, the live line may be used for current sensing, provided that the supply
connections (MAINS) are reversed on the module.

BLOCK DIAGRAM

SA9102
SA9602

POWER

METER

OCTO
COUPLER

SHUNT

POWER
SUPPLY

OUT

NEUTRAL

LIVE

VOLTAGE SENSE

POWER OUTPUT

DR-01447

PM9102AP

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Parameter

Symbol

Min

Max

Unit

Supply Voltage (Note 1)

540

Current Sense Input (Note 1)

-2.5

+2.5

Storage Temperature

STG

-25

+125

°C

Operating Temperature (Note2)

-10

+70

°C

Max Current

MAX

800 (Note 3)

through Sensor

MAX

2000 (Note 4)

Note 1:

Voltages are specified with reference to Live.

Note 2:

The SA9102 and SA9602 integrated circuits are specified to operate over the
temperature range -10°C to +70°C. The module functionality will however
depend upon the external components used.

Note 3:

t = 500ms

Note 4:

t = 1ms

Stresses above those listed under "Absolute Maximum Ratings" may cause permanent damage

to the device. This is a stress rating only. Functional operation of the device at these or any other
conditions above those indicated in the operational sections of this specification, is not implied.
Exposure to Absolute Maximum Ratings for extended periods may affect device reliability.

ELECTRICAL CHARACTERISTICS
(Over the temperature range -10°C to +70°C, unless otherwise specified. Power
consumption figures are applicable to the PM9102APE only.)

Parameter

Symbol

Min

Typ

Max

Unit

Condition

Supply voltage

180

230

265

PM9102APE

(Continuous)

115

135

PM9102APA

Frequency output

FOUTX

Refer to applicable IC data sheet

Power consumption

800

m W

= 230V

Supply direct
from mains

200

m W

5VAC supply

Isolation voltage

2500

Continuous

Output transistor
collector current

=1V

Note 1: Power consumption specifications exclude power consumed by the current

sensor.

ABSOLUTE MAXIMUM RATINGS*

PM9102AP

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Note 2: Isolation voltage may be specified, depending on customer requirements.

CONNECTION DESCRIPTION

Designation

Description

MAINS

Voltage supply connection to Neutral line
Voltage supply connection to Live line

Neutral In

Connection to positive side of current sensor

Neutral Out

Connection to negative side of current sensor

JP1

SA9102/SA9602 output pin selector (Jumper)

SK1

Power measurement output

FUNCTIONAL DESCRIPTION
1.

Power Calculation
In the Application Circuit (Figure 2), the output current from the current sensor will
be between 0 and 16µA (0 to 80A through a shunt resistor of 625µ

). The current

input stage saturates at input currents greater than18µA

RMS

. The mains voltage

(230V + 15% -20%) is used to supply the circuitry with power and for the power
calculation, together with the current information from the current sensor (shunt
resistor).

The SA9102CP, SA9602EP (DIP-20), SA9602HP (DIP-20) and SA9602MP
integrated circuits may be adjusted to accommodate any voltage or current values.
The method of calculating external component values is described in paragraph 5
(Circuit Description).

SAMES offers evaluation module options, namely 230V/80A and 115V/80A.

The calculated power is integrated over time and converted into a corresponding
frequency. The frequency is transmitted as a pulse rate through an opto-coupler.

Electrostatic Discharge (ESD) Protection
The device's inputs/outputs are protected against ESD according to Mil-Std 883C,
method 3015. The modules resistance to transients will be dependant upon the
protection components used.

Power Consumption
The overall power consumption rating for this power metering application (Figure
2), is under 500mW, excluding the current sensor, if a supply is taken directly from
the mains.

Isolation
The pulse output is isolated from the module, which is at mains potential, via an
opto-coupler. (In the event of the use of a current transformer for current sensing,
an opto-coupler would not be required.)

PM9102AP

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Circuit Description
The Application Circuit (Figure 2) details the components required for the power
metering module, using a shunt resistor for current sensing.

In this application the device requires +2,5V, 0V, -2,5V DC supply.

The most important external components are:

and C

are the outer loop capacitors for the two integrated oversampling A/D

converters. The value of these capacitors is 560pF. The actual values determine
signal to noise and stability performance. The tolerance should be within ± 10%.

and C

are the inner loop capacitors of the A/D converters. The optimum value

is 3.3nF. The actual values are uncritical. Values smaller than 0.5nF and larger
than 5nF should be avoided.

, R

and RSH are the resistors defining the current level into the current sense

input. The values should be selected for an input current of 16µA

RMS

into the SA9102

/ SA9602 at maximum line current.

Values for RSH of less than 200µ

should be avoided.

= R

= (I

/16µA

RMS

) * RSH/2

Where

Line current

RSH =

Shunt resistor/termination resistor

, R

and R

set the current for the voltage sense input. The values should be

selected so that the input current into the voltage sense input (virtual ground) is set
to 14µA

RMS

and P

defines all on-chip bias and reference currents. With R

+ P

= 24k

optimum conditions are set. R

+ P

may be varied by ±10% for calibration

purposes. Any change to R

+ P

will affect the output quadratically.

XTAL is a colour burst TV crystal (f = 3.5795MHz) for the oscillator. The oscillator
frequency is divided down to 1.7897MHz on-chip and supplies the A/D converters
and the digital circuitry.

PM9102AP

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Parts List for Application Circuit: Figure 2

Item

Symbol

Description

Detail

IC-1

SA9102CP/EP/FP/HP / SA9602EP/HP/MP DIP-20

IC-2

Optocoupler, 4N35

DIP-6

Diode, Silicon, 1N4148

ZD1

Diode, Zener, 2.4V, 200mW

ZD2

Diode, Zener, 2.4V, 200mW

XTAL

Crystal, 3.5795MHz

Colour burst TV

Resistor, 1.6k

, 1%, metal

Note 1

Resistor, 1.6k

, 1%, metal

Note 1

R3A

Resistor, 1%, metal

Note 2

R3B

Resistor, 1%, metal

Note 2

Resistor, 1M

, ¼W, 1%, metal

Resistor, 470

, 2W, 5%, carbon

Resistor, 24k, ¼W, 1%, metal

Resistor, 22k, ¼W, 1%, metal

Trimpot, 5k

Multi turn

Resistor, 680

, ¼W, 5%

Resistor, 680

, ¼W, 5%

R10

Resistor, 680

, ¼W, 5%

Capacitor, 560pF

Capacitor, 3.3nF

Capacitor, 100nF

C10

Capacitor, 100nF

C11

Capacitor, polyester

Note 2

C13

Capacitor, 100µF, 16V

C14

Capacitor, 100µF, 16V

C15

Capacitor, 820nF

Note 3

JP1

Jumper

RSH

Shunt Resistor, 80A, 50mV (625µ

)

Note 1

Note 1 : Resistor (R1 and R2) values are dependant upon the selected value of R

See paragraph 5 (Circuit Description) when selecting the value for R

Note 2 : See the table below, detailing the component values for the selected voltage

standard.

Note 3 : Capacitor (C15) to be positioned as close as possible to Supply Pins

& V

) of IC-1.

PM9102AP

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Disclaimer:

The information contained in this document is confidential and proprietary to South African Micro-

Electronic Systems (Pty) Ltd ("SAMES") and may not be copied or disclosed to a third party, in whole or in part,
without the express written consent of SAMES. The information contained herein is current as of the date of
publication; however, delivery of this document shall not under any circumstances create any implication that the
information contained herein is correct as of any time subsequent to such date. SAMES does not undertake to inform
any recipient of this document of any changes in the information contained herein, and SAMES expressly reserves
the right to make changes in such information, without notification,even if such changes would render information
contained herein inaccurate or incomplete. SAMES makes no representation or warranty that any circuit designed
by reference to the information contained herein, will function without errors and as intended by the designer.

Any Sales or technical questions may be posted to our e-mail address below:
energy@sames.co.za

For the latest updates on datasheets, please visit out web site:
http://www.sames.co.za

South African Micro-Electronic Systems (Pty) Ltd
P O Box 15888,

33 Eland Street,

Lynn East,

Koedoespoort Industrial Area,

0039

Pretoria,

Republic of South Africa,

Republic of South Africa

Tel:

012 333-6021

Tel:

Int +27 12 333-6021

Fax:

012 333-8071

Fax:

Int +27 12 333-8071

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