sames

FEATURES

Performs bidirectional energy meter-
ing and includes a 7 digit LCD driver
with announciators

4 externally selectable on-chip tariff
registers

An additional total energy register

Meets the accuracy requirements for
Class 1 AC Watt hour meters

Optical interface for electronic reading
according to IEC1107 Mode D

1/12

Pulse output for calibration

Total power consumption rating below
600mW

Uses a shunt resistor for current sens-
ing

Operates over a wide temperature
range

Demonstration software included

MONOCHIP SINGLE PHASE BIDIRECTIONAL

KILOWATT HOUR METERING MODULE

PM9109BFX

PDS038-SA9109-001

REV. 3

28-06-00

SA9109B APPLICATION NOTE

PM9109BF

DESCRIPTION

The SAMES monochip single phase bidirectional kilowatt hour metering module, the

PM9109BF, provides all the required metering functions including energy measure-
ment, a 7 digit LCD driver, a tariff selection facility, an optical port as well as a pulse
output for calibration purposes.

Energy consumption is determined by the power measurement being integrated over

time.

This method of calculation takes the power factor into account.
This application utilises the SAMES SA9109BFA monochip single phase bidirectional

kilowatt hour metering IC for energy 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.

PM9109BF

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ABSOLUTE MAXIMUM RATINGS*

Parameter

Symbol

Min

Max

Unit

Supply Voltage (Note 1)

540

Current Sense Input (Note 1)

-2.5

Storage Temperature

STG

-25

+125

癈

Operating Temperature

-10

+70 (Note 2)

癈

Max Current

MAX

800 (Note 3)

through sensor

MAX

2000 (Note 4)

Note 1:

Voltages are specified with reference to Live.

Note 2:

The SA9109B integrated circuit is specified to operate over the temperature
range -10癈 to +70癈. 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.

BLOCK DIAGRAM

SCROLL

SA9109B

SHUNT

PO W ER

SUP PL Y

BAT T ERY

BAC KUP

LOAD

DIS PLAY

DR-00995

OPTICAL

PORT

PULSE

OUTPUT

ISOLATED

CALIBRATION

INTERFACE

PGM

DTA

CLK

RES ET

T AR IF F

SEL ECT

PM9109BF

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3/18

ELECTRICAL CHARACTERISTICS
(Over the temperature range -10癈 to +70癈, unless otherwise specified. Power
consumption figures are applicable to the PM9109BFE only.)

Parameter

Symbol

Min

Typ

Max

Unit

Condition

Supply Voltage

180

230

265

PM9109BFE

(Continues)
Power Consumption

500

= 230V

Supply direct
from mains

Isolation Voltage

2500

Continuous

Opto-coupler Output
Current

= 1V

Opto-coupler Input
Current

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

sensor.

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

PIN 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

SK1

Isolated programming interface

5-Pin

Header

connector

SK2

Isolated pulse output

2-Pin

Header

connector

PM9109BF

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FUNCTIONAL DESCRIPTION

Energy Calculation
This Application Note should be read in conjunction with the SA9109B Data Sheet.

In the Application Circuit (see Figure 2), the output current from the current sensor
will be between 0 and 16

�

A (0 to 80A through a shunt resistor of 625

�

The

current input stage of the module saturates at input currents greater than
18礎RMS. The mains voltage + 15% - 20%) is used to supply the circuitry with
power and to perform the energy calculation, together with the current information
from the current sensor (shunt resistor).

The SA9109BF integrated circuit may be adjusted to accommodate any voltage or
current values. The method for calculating external component values is described
in paragraph 9 (Circuit Description).

The accumulated energy is directly displayed on a 7 digit LCD. This unique
application offers a host of additional features, which are dealt with below.

Electrostatic Discharge (ESD) Protection
The device's inputs/outputs are protected against ESD according to the 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 600mW, excluding the current sensor, when the supply is taken directly
from the mains.

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

Isolated Programming Interface
This isolated interface is provided to allow the user to programme the tariff register
values, calibration constants and manufacturer/meter identification codes. This
port is enabled by inserting the jumpers J8, J9 and J10. The programming may be
performed via the parallel port of a personal computer.

PM9109BF

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The designation of the pins on connector SK1 are given below:

PM9109B

PC Parallel Connectors (Suggested)

Pin

Description

Pin

Description

GND

PCLK

PDTA

PGM

Note: The recommended connections above are applicable for the demonstration
software provided with the PM9109BF.

Optical Port
The optical port has been designed to meet the IEC1107 Mode D specification.
This facility offers a pulse output as well as a serial data meter reading facility.

Three types of interfacing elements from the PM9109BF are available:

a) Infra-red optical port

b) Red LED

c) Opto-coupler

In order to maximise the intensity of the element, it is suggested that only one of
the outputs be used at any one time.

Jumper

Element

Opto Coupler

Infra Red LED

Red LED

Liquid Crystal Display (LCD)
The PM9109BF includes a LCD comprising of seven digits with announciators.

To cater for compatibility with future devices, four jumpers are provided for
backplane driving configurations. The PM9109BF boards are shipped to the
customer with jumpers in a default configuration.

This note refers to the SA9109B data sheet throughout the text and it is
recommended that a copy of the data sheet of the SA9109B is on hand when reading
through this description.

PM9109BF

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The SA9109B data sheet uses 80A and 230V for rated current and rated voltage
when explaining functionality of the device. This is just for example and any other
rated values may be used. All AC voltages and currents are RMS values unless
otherwise specified.

Let us assume that we want to measure the energy for current range 0 ... 200A
and voltage range 0 ... 120V. In this case I

=200A is a rated line current and

=120V is a rated line voltage. Rated line power is 200A * 120V = 24kW.

Three simple steps must now be followed:

STEP 1

Select the shunt resistor RSH value and adjust the values of resistors R1, R2 in
such a way that current flowing into the device's current sense input (pins 9 and
10) is 16礎 for rated line current (200A). This should be simple and straightforward
task because current sense input of the device (pins 9 and 10) behaves as a
virtual short. For this example a shunt resistor with a value of 625�

is selected.

This will result in the current sense input resistors having a value of R1=R2=1.6k

It is important to ensure that the voltage drop across the shunt resistor is not too
low as the precision may suffer.

STEP 2

Choose resistors R3, R6 and R4 such that current flowing into the voltage sense
input (pin 8) is 14礎 for rated line voltage (120V). R3 and R4 forms a voltage
divider from line voltage to approx. 10-20V and R4 is a serial resistor for setting
the required voltage sense current of 14礎. Input to the device again behaves as
a virtual short (with respect to GND - pin 11).

The value of capacitor C5 introduces a phase shift which can be used to
compensate for current transformers, it is chosen to ensure that it forms a short
with respect to R4 for typical mains frequency.

For this example R3 = 106K, R6 = 14K and R4 = 1M.

STEP 3

To calculate how much energy is represented by one pulse on output SDO (pin
39) and one Display increment, the following is now performed:

PM9109BF

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7/18

The formula for f

as shown in the data sheet can be simplified if:

FOSC = 3.5795MHz

recommended crystal with this frequency is used

= 16礎

by choice of correct values for RSH, R1 and R2 (STEP 1)

= 14礎

by choice of correct values for R3, R6 and R4 (STEP 2)

= 50礎

recommended reference setting with value of 24K for

resistor R7

If these values are substituted into the original formula:

= 40062.5/Ks

(1)

Ks is an integer constant which can be programmed into the device.
Range is 1025 ... 16384.

Display increment frequency is 64 times lower (refer to diagram "Programmable
slope divider" in the datasheet).

Display increment = 40062.5/(Ks*64) = 626/Ks

(2)

Substituting Ks into each of these two formulae gives ranges for f

and Display

increment:

= 39.0854Hz ... 3.6659Hz

(3)

Display increment = 0.6107Hz ... 0.0573Hz (4)

These values are min and max for f

at all rated conditions because of properly

adjusted resistor values (chosen in STEP 1 and STEP 2) to ensure that I

= 16礎

and I

= 14礎.

How much energy is now represented by one pulse on SDO?

In this example the rated power is 24000W which gives energy 24000Ws for 1
second. Energy for 1 pulse on SDO is then 24000Ws/f

. Now substitute ranges

given in statement (3) above:

Energy for 1 pulse on SDO

= (24000/39.0854)Ws ... (24000/3.6659)Ws
= 614.04Ws ... 6546.82Ws

PM9109BF

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Similarly by using (4)

Energy for 1 Display increment

= (24000/0.6107)Ws ... (24000/0.0573)Ws
= 39299.2Ws ... 418848.2Ws
= 0.0109kWh ... 0.1164kWh

Any value in this range can be chosen by programming Ks into the device.

How is the calibration factor, Ks, derived?

Ks =

(626 * E

) / (V

* I

)

(5)

or Ks = (626 * 3600 * 1000 * E

kWh

) / (V

* I

) (6)

where

is rated line current

is rated line voltage

is energy for one Display increment in Ws

kWh

is energy for one Display increment in kWh

This formula is valid only if 16礎 flows into current sense input for rated line
current I

and 14礎 flows into voltage sense input for rated line voltage V

(in

other words - resistor adjustments as shown as example in STEP 1 and STEP 2
must be carried out).

For practical reasons it is standard to use 0.1kWh for 1 Display increment.

Using formula (6) :

Ks = (626 * 3600 * 1000 * 0.1) / (120 * 200) = 9390

It can be derived that a value of Ks=9390 must be programmed into the device for
0.1kWh for one Display increment, if I

=200A and V

=120V. This constant

may vary �10% for calibration purposes.

Using this approach it is shown that:

1) the SA9109B device can be adjusted to any rated values (even orders of

magnitude higher or lower than in this example);

2) ranges for energy per Display increment can be calculated.

This approach also applies to the SA9110A.

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Tariff, Scroll and Reset Functions
Tariff Selection
A dual DIP switch provides the user with the facility to set the active tariff register
in which consumption will be accumulated.
The active register is indicated on the LCD.

Scroll Facility
The 4 registers may be sequentially displayed by activating the scroll button. The
contents of the register selected for display is retained on the display for a period
of 10 seconds, provided that the push button is not activated during this period.
After the 10 seconds has elapsed, the display defaults to the "active" register
defined by the status of the tariff DIP switches.

The register selected for display via the scroll button is indicated by the relevant
announciators.

Reset Function
By pressing the Reset button the contents of the RAM of the SA9109B device is
set to the default conditions.

Jumpers J8, J9 and J10 must be removed to use this feature.

It is strongly recommended that the provision of this facility is not made available
on production meters.

Circuit Description
The Application Circuit (Figure 2) shows the components required for a power
metering application, using a shunt resistor for current sensing. In this application
the circuitry requires a +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
tolerances 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 R

are the resistors defining the current level into the current sense

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

�

RMS

into the

SA9109B, at rated line current.

PM9109BF

10/18

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Values for RSH of less than 200

�

should be avoided.

= R

= (I

/16

�

RMS

) * R

Where

Line current

Shunt 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 14

�

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

= 24k

, optimum

conditions are set. R

may be varied within �10% for calibration purposes. Any

change to R

will affect the energy calculation 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.

10. Demonstration Software

The accompanying diskette requires an IBM or compatible PC with MS-DOS
installed. This software, supplied on a 1.4M 3�" disk, will allow the user to read and
write settings from/to the demonstration unit.

Context sensitive help screen for each input field or command prompt are available
by invoking [alt] H or [F1] key.

An introduction is available by pressing the [F1] key immediately after installation.

INSTALLATION

1. Copy the file SA9109.exe to the directory from which to operate.
2. Connect the demonstration board to either COM1 or COM2 (default) of the

PC.

3. The demonstration board may now be connected to the load and the mains

supply attached as suggested in the Functional Description section of the
appropriate Application Note.

4. At the DOS prompt type SA9109 and carriage return [CR] to invoke the

programme.

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RUNNING THE PROGRAMME
On entering the programme, the user will be offered a selection of fields to
choose from. A brief description of each field is given below:
Comms

Selection of serial communication port connecting the

demoboard containing the SA9109B to the PC.

Read

Start task of reading from attached SA9109B device.

Write

Data stored in the input boxes displayed on the right hand
side of the screen will be written via the parallel port connected
on SK1.

Capture boxes with a .............. on display will write the value
displayed in the Read section for that parameter.

Help

Screen of useful keystrokes used in the programme.

A number of input boxes are available to the user to enter register start values,
identity numbers, and the slope factor for the output frequency. Input boxes
are:

TARIFF 1

Initial value from which the device must start accumulation of
data of chosen as "Active" tariff register

TARIFF 4

Sign +/-

The register value input for Tariff 1 -- Tariff 4 may be either a
positive (+) or negative (-) value.

Total

As with the tariff registers, an initial value from which accumu-
lation of registers totals will begin may be entered. This regis-
ter, in practice, will contain the sum of the four tariff registers.
Updating of this register takes place automatically when either
of the tariff registers increment during power consumption.

I.D. man/

Numeric code to allow the supplier to individually attach a ref-

I.D. sys

erence identifier to a metering unit.

Type

This field should remain as per default (SA9109B selected).
The SA9109B will increment irrespective of energy direction.

PM9109BF

12/18

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Slope

The output frequency at SDO (f

) may be adjusted during cali

bration according to the formula:

= 11.16 x

FOSC

40062.5

3.5795E6 I

where

FOSC =

Oscillator frequency (2MHz --- 4MHz)

Input current for current sensor input
(16礎 at rated line current)

Input current for voltage sensor input
(14礎 at rated line voltage)

Reference current (Typically 50礎)

Slope constant (1025 --- 16384)

(Default 11389)

For default rated conditions the output frequency on SDO will be 3.5Hz. The
display is incremented after every 64th pulse on SDO as shown in the block
diagram below.

USEFUL NOTES:
1.

A context sensitive help screen is available throughout the programme
and is invoked by using [F1] or [ALT]-H.

Hot key features are available for a number of functions and can be
identi

fied

for use by the highlighted character of the field. For example,

[ALT]C for COMMS field.

To exit from the programme [Esc] or [Alt]-X

40062.5*

Pulses / s

DR-00938

1 / K

Display

Increment

1 / 64

PM9109BF

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Figure 2: Application Circuit

S
A

9109

PPL

DR-

BAT

2
C

CIN

CIP

V DD

IIP

IIN

S
E

J10

]

O
S

O
M

O
S

33
34
35
36

31
32

/im

p/k

rro

LC
D

Tot

a
l

24
25
26
27
28

19
20
21
22

U
2

D
_

L
E

U
1

12
38

S
K
1

U
3

S
K
2

SSV

PM9109BF

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15/18

Parts List for Application circuit: Figure 2

Item Symbol

Description

Detail

U-1

SA9109BF

PLCC-44

U-2

ILQ74 (Quad opto-coupler)

DIP-16

U-3

4N35 (opto-coupler)

DIP-6

XTAL

Crystal 3.5795MHz

Colour burst TV

Resistor, 1.6k

, 1%, metal

Note 1

Resistor, 1.6k

, 1%, metal

Note 1

R3A

Resistor, 180k

, 1%, metal

Note 2

R3B

Resistor, 200k

, 1%, metal

Note 2

Resistor, 24k

, 1%, metal

Note 2

Resistor, 470k

, 2W, 5%

Resistor, 24k

, 1%, metal

Note 2

Resistor, 24k

, 1%, metal

Resistor, 2M

, 1%, metal

Resistor, 680

, 1%, metal

R10

Resistor, 680

, 1%, metal

R11

Resistor, 680

, 1%, metal

R12

Resistor, 2.2k

, 1%, metal

R13

Resistor, 2.2k

, 1%, metal

R14

Resistor, 2.2k

, 1%, metal

R15

Resistor, 2.2k

, 1%, metal

R16

Resistor, 2.2k

, 1%, metal

RSH

Shunt resistor, 80A, 50mV (625

�

)

Note 1

Capacitor, 560pF

Capacitor, 3.3nF

Capacitor, 470nF, polyester, 250VAC

Capacitor, 1

�

F, 16V

Capacitor, 100nF

Capacitor, 820nF

C10

Capacitor, 100

�

F, 16V

C11

Capacitor, 100

礔

, 16V

C12

Capacitor, 820nF

C13

Capacitor, 100nF

BAT

Battery, 1.2V

IR LED

Infrared light emitting diode

RED LED Red light emitting diode

Photo transistor

Diode, 1N4148

PM9109BF

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Parts List for Application circuit: Figure 2 (continued)

Item Symbol Description

Detail

Diode 1N4148

ZD1

Zener Diode, 2.4V

ZD2

Zener Diode, 2.4V

ZD3

Zener Diode, 47V

SCROLL NO, push button

RESET

NO, push button

TARIFF

DIP switch, 2 pole

LCD

OEL-7678*

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

See paragraph 9 (Circuit Description) when selecting the value of RSH.

Note 2: See the table below for resistor values, assuming a 115V/80V metering

application is required.

Description

Item

Symbol

115V/80A

Detail

R3A

120k

R3B

82k

�

ORDERING INFORMATION

Part Number

Description

PM9109BFE

230V, 80A Module

PM9109BFA 115V, 80A Module

*The LCD display is available from:
JEBON CORPORATION
Unit 709, Poongsan Factoria Town,
1141-2, Baegsok-Dong, Ilsan-District,
Koyangcity, Kyonggi-Do, 411-360, Korea
Tel: +82-31-902-9161 (12 lines)
Fax: +82-31-902-7775/7776

Web site: http://www.jebon.com

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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, 0039

Koedoespoort Industrial Area,

Republic of South Africa,

Pretoria,

Republic of South Africa

Tel:

012 333-6021

Tel:

Int +27 12 333-6021

Fax:

012 333-8071

Fax:

Int +27 12 333-8071

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.

协谢械泻褌褉芯薪薪褘泄 泻芯屑锌芯薪械薪褌: PM9109BFA

协谢械泻褌褉芯薪薪褘泄泻芯屑锌芯薪械薪褌: PM9109BFA