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FEATURES
SA9109B APPLICATION NOTE
PM9109BF
MONOCHIP SINGLE PHASE BIDIRECTIONAL
KILOWATT HOUR METERING MODULE
! 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
DESCRIPTION
The SAMES monochip single phase bidirectional kilowatt hour metering module, the
PM9109BF, provides all the required metering functions including energy measurement, 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.
! 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
PM9109BFX PDS038-SA9109-001 REV. 3 28-06-00
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PM9109BF
BLOCK DIAGRAM
LOAD
DISPLAY
SHUN T
NL
SA9109B
POW ER
SUPPLY
SCROLL
BAT T ERY
BACKUP
RES E T
CL K
DT A
PGM
TARIFF
SEL ECT
ISOLATED
CALIBRATION
INTERFACE
PULSE
OUT P UT
OPTICAL
PORT
DR-00995
ABSOLUTE MAXIMUM RATINGS*
Parameter Symbol Min Max Unit
Supply Voltage (Note 1) V
Current Sense Input (Note 1) V
Storage Temperature T
Operating Temperature T
Max Current I
through sensor I
STG
MAX
MAX
AC
IV
-2.5 V
-25 +125 °C
O
-10 +70 (Note 2) °C
540 V
800 (Note 3) A
2000 (Note 4) A
Note 1: Voltages are specified with reference to Live.
Note 2: The SA9109B integrated circuit is 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.
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PM9109BF
ELECTRICAL CHARACTERISTICS
(Over the temperature range -10°C to +70°C, unless otherwise specified. Power
consumption figures are applicable to the PM9109BFE only.)
Parameter Symbol Min Typ Max Unit Condition
Supply Voltage
(Continues)
Power Consumption
V
AC
1
180 230 265 V PM9109BFE
500 mW VAC = 230V
Supply direct
from mains
Isolation Voltage
Opto-coupler Output
Current
Opto-coupler Input
Current
2
V
IS
I
O
I
I
2500 V Continuous
10 mA VOL = 1V
10 mA
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
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PM9109BF
FUNCTIONAL DESCRIPTION
1. 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 16µA (0 to 80A through a shunt resistor of 625µΩ). The
current input stage of the module saturates at input currents greater than
18µARMS. 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.
2. 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.
3. 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.
4. 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).
5. 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.
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The designation of the pins on connector SK1 are given below:
PM9109B PC Parallel Connectors (Suggested)
Pin Description Pin Description
1 GND 18 GND
2PB2D1
3 PCLK 4 D3
4 PDTA 5 D4
5 PGM 3 D2
Note: The recommended connections above are applicable for the demonstration
software provided with the PM9109BF.
6. 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
PM9109BF
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
J5 Opto Coupler
J6 Infra Red LED
J7 Red LED
7. 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.
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PM9109BF
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 ILR=200A is a rated line current and
VLR=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 16µA 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 625µΩ is selected.
This will result in the current sense input resistors having a value of R1=R2=1.6kΩ.
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 14µA 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 14µA. 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:
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PM9109BF
The formula for fP, as shown in the data sheet can be simplified if:
FOSC = 3.5795MHz recommended crystal with this frequency is used
II = 16µA by choice of correct values for RSH, R1 and R2 (STEP 1)
IV = 14µA by choice of correct values for R3, R6 and R4 (STEP 2)
IR = 50µA recommended reference setting with value of 24K for
resistor R7
If these values are substituted into the original formula:
fP = 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 fP and Display
increment:
fP = 39.0854Hz ... 3.6659Hz (3)
Display increment = 0.6107Hz ... 0.0573Hz (4)
These values are min and max for fp at all rated conditions because of properly
adjusted resistor values (chosen in STEP 1 and STEP 2) to ensure that II= 16µA
and IV = 14µA.
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/fP. 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
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PM9109BF
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 * EWs) / (VLR * ILR) (5)
or Ks = (626 * 3600 * 1000 * E
where I
LR
V
E
E
is rated line current
is rated line voltage
LR
is energy for one Display increment in Ws
ws
is energy for one Display increment in kWh
kWh
) / (VLR * ILR) (6)
kWh
This formula is valid only if 16µA flows into current sense input for rated line
current ILR and 14µA flows into voltage sense input for rated line voltage VLR (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 ILR =200A and VLR =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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8. 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.
PM9109BF
9. 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:
C1 and C2 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%.
C3 and C4 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.
R2, R1 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
SA9109B, at rated line current.
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into the
RMS
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PM9109BF
Values for RSH of less than 200µΩ should be avoided.
R1 = R2 = (IL/16µA
Where I
) * RSH/2
RMS
= Line current
L
RSH= Shunt resistor
R3A, R3B , R6 and R4 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.
R7 defines all on-chip bias and reference currents. With R
= 24kΩ, optimum
7
conditions are set. R7 may be varied within ±10% for calibration purposes. Any
change to R7 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 3½" 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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PM9109BF
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 register, 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.
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PM9109BF
Slope The output frequency at SDO (fp) may be adjusted during cali
fp = 11.16
where
FOSC = Oscillator frequency (2MHz --- 4MHz)
bration according to the formula:
FOSC x II IV x 40062.5
x
3.5795E6 I
2
K
R
s
I
I
= Input current for current sensor input
(16µA at rated line current)
I
V
= Input current for voltage sensor input
(14µA at rated line voltage)
I
R
K
= Reference current (Typically 50µA)
= Slope constant (1025 --- 16384)
S
(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.
40062.5*
Pulses / s
DR-00938
1 / K
s
1 / 64
Di sp la y
Increment
f
p
USEFUL NOTES:
1. A context sensitive help screen is available throughout the programme
and is invoked by using [F1] or [ALT]-H.
2. Hot key features are available for a number of functions and can be
identified for use by the highlighted character of the field. For example,
[ALT]C for COMMS field.
3. To exit from the programme [Esc] or [Alt]-X
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Figure 1: Connection Diagram
PM9109BF
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PM9109BF
Figure 2: Application Circuit
+5V
J7
J6
J5
R1 3
R1 2
R1 1
U3
12387
564
12
RED_ LED
IR_ LE D
U2
13 15 1016 9
R1 6
14
R1 5R1 4
11 12
+5V
56
SK2
4
1
SK1
1
J4
LCD
19
J3
20
% E rro r
21
22
23
24
25
PB
26
27
28
29
30
31
32
33
34
35
36
242322
SR[1 ]
C[3 ]
C[0 ]
C[1 ]
COFF
SR[0 ]
SOUT
PCLK
PDTA
PGM
OSC O
OSC I
IIP
IIN
9
10
R2
SS
V
TAR
SCROLL
U1
X1
1
44
39
43
40
41
42
37
38
Q1
J9
J8
J10
RESE T
R4
im p/kW h
C[4 ]
C6
R1
18
17
J1
kWshJ2W h /im p
Hz 32 1
16
15
14
. . .
Tot al
13
12
11
10
9
8
T2 T3 T4
. . . . . . . .
7
6
T1
5
. . . .
4
3
2
T4 COST
1
T3 COM.T1 COST
T2 TOTAL
30
31
29
282726
C[7 ]
C[9 ]
C[8 ]
C[10 ]
C[6 ]
C[5 ]25C[2 ]
SA9109B
IVN
VREF
V
12
17
8
R7
+5V
343332
DD
21
20
19
35
36
18
R[1 ]
R[3 ]
R[2 ]
C[12 ]
R[0 ]
C[13 ]
C[11 ]
GND
11
CPIP
16
CPIN
15
CPOP
14
CPON
C1 C3
13
CON
7
COP
6
CIN
5
CIP
C4 C2
SS
V
3
D3
4
VBA
2
C1 2C1 3
D4
R8
C7
+5V
BAT.
GND
C9
C8
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ZD1
R3 b
R6
R3 a
RSH
LOAD
C5
R5
R9
D1
ZD2
R1 0
C1 0
C1 1
ZD3
D2
DR-009 9 7
N
L
SUPPLY
PM9109BF
Parts List for Application circuit: Figure 2
Item Symbol Description Detail
1 U-1 SA9109BF PLCC-44
2 U-2 ILQ74 (Quad opto-coupler) DIP-16
3 U-3 4N35 (opto-coupler) DIP-6
4 XTAL Crystal 3.5795MHz Colour burst TV
5 R1 Resistor, 1.6kΩ, 1%, metal Note 1
6 R2 Resistor, 1.6kΩ, 1%, metal Note 1
7 R3A Resistor, 180kΩ, 1%, metal Note 2
8 R3B Resistor, 200kΩ, 1%, metal Note 2
9 R4 Resistor, 24kΩ, 1%, metal Note 2
10 R5 Resistor, 470kΩ, 2W, 5%
11 R6 Resistor, 24kΩ, 1%, metal Note 2
12 R7 Resistor, 24kΩ, 1%, metal
13 R8 Resistor, 2MΩ, 1%, metal
14 R9 Resistor, 680Ω, 1%, metal
15 R10 Resistor, 680Ω, 1%, metal
16 R11 Resistor, 680Ω, 1%, metal
17 R12 Resistor, 2.2kΩ, 1%, metal
18 R13 Resistor, 2.2kΩ, 1%, metal
19 R14 Resistor, 2.2kΩ, 1%, metal
20 R15 Resistor, 2.2kΩ, 1%, metal
21 R16 Resistor, 2.2kΩ, 1%, metal
22 RSH Shunt resistor, 80A, 50mV (625µΩ) Note 1
23 C1 Capacitor, 560pF
24 C2 Capacitor, 560pF
25 C3 Capacitor, 3.3nF
26 C4 Capacitor, 3.3nF
27 C5 Capacitor, 470nF, polyester, 250VAC
28 C6 Capacitor, 1µF, 16V
29 C7 Capacitor, 100nF
30 C8 Capacitor, 100nF
31 C9 Capacitor, 820nF
32 C10 Capacitor, 100µF, 16V
33 C11 Capacitor, 100µF, 16V
34 C12 Capacitor, 820nF
35 C13 Capacitor, 100nF
36 BAT Battery, 1.2V
37 IR LED Infrared light emitting diode
38 RED LED Red light emitting diode
39 Q1 Photo transistor
40 D1 Diode, 1N4148
41 D2 Diode, 1N4148
42 D3 Diode, 1N4148
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PM9109BF
Parts List for Application circuit: Figure 2 (continued)
Item Symbol Description Detail
43 D4 Diode 1N4148
44 ZD1 Zener Diode, 2.4V
45 ZD2 Zener Diode, 2.4V
46 ZD3 Zener Diode, 47V
47 SCROLL NO, push button
48 RESET NO, push button
49 TARIFF DIP switch, 2 pole
50 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
7 R3A 120kΩ
8 R3B 82kΩ
27 C5 1µF
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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Note:
PM9109BF
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PM9109BF
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, 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
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