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SA9109B APPLICATION NOTE
PM9109BF
MONOCHIP SINGLE PHASE BIDIRECTIONAL
KILOWATT HOUR METERING MODULE
FEATURES
!
!
!
!
!
Performs bidirectional energy metering 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
!
!
!
!
!
Pulse output for calibration
Total power consumption rating below
600mW
Uses a shunt resistor for current sensing
Operates over a wide temperature
range
Demonstration software included
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.
1/12
PM9109BFX
PDS038-SA9109-001
REV. 3
28-06-00
PM9109BF
BLOCK DIAGRAM
LOAD
DIS PLAY
SCROLL
RE S E T
CLK
DTA
PGM
SHUNT
T AR IF F
S E L E CT
ISOLATED
CALIBRATION
INTERFAC E
SA9 109 B
PULSE
OUTPUT
PO W ER
S UP P L Y
L
OPTICAL
POR T
BAT T E RY
BAC KUP
DR-00995
N
ABSOLUTE MAXIMUM RATINGS*
Parameter
Symbol
Supply Voltage (Note 1)
V AC
Current Sense Input (Note 1)
VIV
Storage Temperature
TSTG
Operating Temperature
TO
Max Current
IMAX
through sensor
IMAX
Note 1:
Note 2:
Min
-2.5
-25
-10
Max
540
V
+125
+70 (Note 2)
800 (Note 3)
2000 (Note 4)
Unit
V
°C
°C
A
A
Voltages are specified with reference to Live.
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.
2/18
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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
VAC
180
230
265
V
PM9109BFE
(Continues)
Power Consumption 1
500
mW
VAC = 230V
Supply direct
from mains
2
Isolation Voltage
VIS
2500
V
Continuous
Opto-coupler Output
IO
10
mA
VOL = 1V
Current
Opto-coupler Input
II
10
mA
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
MAINS
NEUTRAL IN
NEUTRAL OUT
SK1
5-Pin
Header
connector
SK2
2-Pin
Header
connector
Description
Voltage supply connection to Neutral line
Voltage supply connection to Live line
Connection to positive side of current sensor
Connection to negative side of current sensor
Isolated programming interface
Isolated pulse output
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3/18
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.
3.
4.
5.
4/18
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.
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PM9109BF
The designation of the pins on connector SK1 are given below:
PM9109B
Pin
Description
1
GND
2
PB
3
PCLK
4
PDTA
5
PGM
PC Parallel Connectors (Suggested)
Pin
Description
18
GND
2
D1
4
D3
5
D4
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
In order to maximise the intensity of the element, it is suggested that only one of
the outputs be used at any one time.
7.
Jumper
Element
J5
J6
J7
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.
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5/18
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
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= (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 * EkWh) / (VLR * ILR)
(6)
where
ILR
VLR
Ews
E kWh
is
is
is
is
rated line current
rated line voltage
energy for one Display increment in Ws
energy for one Display increment in 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 V LR (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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PM9109BF
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.
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 C 4 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 16µARMS into the
SA9109B, at rated line current.
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9/18
PM9109BF
Values for RSH of less than 200µΩ should be avoided.
R1 = R2 = (IL/16µA RMS) * RSH/2
Where
IL
=
RSH =
Line current
Shunt resistor
R3A, R 3B , 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 R7 = 24kΩ, optimum
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.
10/18
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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 accumulation 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/
I.D. sys
Numeric code to allow the supplier to individually attach a reference 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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11/18
PM9109BF
Slope
The output frequency at SDO (fp) may be adjusted during cali
bration according to the formula:
fp = 11.16 x
FOSC
I I
40062.5
x I V x
2
3.5795E6
IR
Ks
where
FOSC =
Oscillator frequency (2MHz --- 4MHz)
II
=
IV
=
IR
=
Input current for current sensor input
(16µA at rated line current)
Input current for voltage sensor input
(14µA at rated line voltage)
Reference current (Typically 50µA)
KS
=
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.
40062.5*
Pulses / s
1/K s
1 / 64
Display
Increment
fp
DR-00938
USEFUL NOTES:
12/18
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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PM9109BF
Figure 1: Connection Diagram
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13/18
RSH
L
N
SUPPL Y
L OAD
Z D3
D R -0 0 9 9 7
D2
D1
R5
C5
R6
R3 a
C1 1 R1 0
C1 0
R9
Z D2
Z D1
R3 b
C8 C9
C7
+5V
R1
R2
GND
R8
C6
D4
+5V
BAT .
D3
R7
R4
C 1 2C 1 3
2
3
11
17
12
8
9
10
X1
R E SE T
VBA
VS S
GND
VD D
VREF
IV N
IIP
IIN
R1 5
J10
1
C4
2
SK1
8
J8
R1 6
J9
SA9109B
C2
Q1
12 14 13 15 16 10
3
C1
CIN
5
R1 4
11
+5V
4
COP
6
38
6
CON
7
C3
U1
U2
C O F F 22
C [0 ] 2 3
C [1 ] 2 4
C [2 ] 2 5
C [3 ] 2 6
C [4 ] 2 7
C [5 ] 2 8
C [6 ] 2 9
C [7 ] 3 0
C [8 ] 3 1
C [9 ] 3 2
C [ 1 0 ]3 3
34
C [1 1 ]
C [ 1 2 ]3 5
C [ 1 3 ]3 6
R [0 ] 1 8
R [1 ] 1 9
R [2 ] 2 0
21
R [3 ]
9
7
2
1
R1 3
R E D_ L E D
R1 1
U3
R1 2
1
5 6
SK2
I R_ L E D
4
T AR
T1
T2
T3
T4
.
.
C OS T
TOT AL
C OM
C OS T
.
J7
J6
J5
VS S
+5V
T1
.
.
.
T2
.
.
.
T3
.
.
.
.
Total
.
T4
.
26
25
24
5
40
CP ON
13
OS CI
37
OS CO
CIP
4
42
P GM
41
PDT A
CP OP
14
36
35
34
33
32
1
2
3
4
5
6
PCL K
43
PB
S O U T 39
S R [0 ] 44
S R [1 ] 1
CP IP
16
CP IN
15
31
30
29
28
27
7
8
9
10
23
22
14
15
11
12
13
sames
.
J4
J1
J2
% E rro r
im p/k W h
Hz 32 1
kWsh
W h /im p
LCD
J3
21
20
19
14/18
16
17
18
1
PM9109BF
Figure 2: Application Circuit
S CROL L
PM9109BF
Parts List for Application circuit: Figure 2
Item Symbol
1
U-1
2
U-2
3
U-3
4
XTAL
5
R1
6
R2
7
R3A
8
R3B
9
R4
10
R5
11
R6
12
R7
13
R8
14
R9
15
R10
16
R11
17
R12
18
R13
19
R14
20
R15
21
R16
22
RSH
23
C1
24
C2
25
C3
26
C4
27
C5
28
C6
29
C7
30
C8
31
C9
32
C10
33
C11
34
C12
35
C13
36
BAT
37
IR LED
38 RED LED
39
Q1
40
D1
41
D2
42
D3
Description
SA9109BF
ILQ74 (Quad opto-coupler)
4N35 (opto-coupler)
Crystal 3.5795MHz
Resistor, 1.6kΩ, 1%, metal
Resistor, 1.6kΩ, 1%, metal
Resistor, 180kΩ, 1%, metal
Resistor, 200kΩ, 1%, metal
Resistor, 24kΩ, 1%, metal
Resistor, 470kΩ, 2W, 5%
Resistor, 24kΩ, 1%, metal
Resistor, 24kΩ, 1%, metal
Resistor, 2MΩ, 1%, metal
Resistor, 680Ω, 1%, metal
Resistor, 680Ω, 1%, metal
Resistor, 680Ω, 1%, metal
Resistor, 2.2kΩ, 1%, metal
Resistor, 2.2kΩ, 1%, metal
Resistor, 2.2kΩ, 1%, metal
Resistor, 2.2kΩ, 1%, metal
Resistor, 2.2kΩ, 1%, metal
Shunt resistor, 80A, 50mV (625µΩ)
Capacitor, 560pF
Capacitor, 560pF
Capacitor, 3.3nF
Capacitor, 3.3nF
Capacitor, 470nF, polyester, 250VAC
Capacitor, 1µF, 16V
Capacitor, 100nF
Capacitor, 100nF
Capacitor, 820nF
Capacitor, 100µF, 16V
Capacitor, 100µF, 16V
Capacitor, 820nF
Capacitor, 100nF
Battery, 1.2V
Infrared light emitting diode
Red light emitting diode
Photo transistor
Diode, 1N4148
Diode, 1N4148
Diode, 1N4148
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Detail
PLCC-44
DIP-16
DIP-6
Colour burst TV
Note 1
Note 1
Note 2
Note 2
Note 2
Note 2
Note 1
15/18
PM9109BF
Parts List for Application circuit: Figure 2 (continued)
Item Symbol
43
D4
44
ZD1
45
ZD2
46
ZD3
47 SCROLL
48
RESET
49
TARIFF
50
LCD
Description
Diode 1N4148
Zener Diode, 2.4V
Zener Diode, 2.4V
Zener Diode, 47V
NO, push button
NO, push button
DIP switch, 2 pole
OEL-7678*
Detail
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.
Item
7
8
27
Symbol
R3A
R3B
C5
Description
115V/80A
120kΩ
82kΩ
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
16/18
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Detail
PM9109BF
Note:
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17/18
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:
[email protected]
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:
Fax:
18/18
012 333-6021
012 333-8071
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