SA9603C
PRELIMINARY
sames
SA9603C
SINGLE PHASE BIDIRECTIONAL POWER/ENERGY
METERING IC WITH SERIAL INTERFACE
FEATURES
■
Performs bidirectional active and
reactive power/energy, frequency and
voltage measurement
■
Meets the IEC 521/1036 Specification
requirements for Class 1 AC Watt hour
meters
■
Protected against ESD
■
Total power consumption rating below
25mW
DESCRIPTION
The SAMES SA9603C bidirectional single
phase power/energy metering integrated
circuit has a serial interface with a RS232
protocol, ideal for use with a µ-Controller.
The SA9603C performs the calculation for
active and reactive power.
The SA9603C is a direct replacement for
the SA9103C with additional features for
the fast reading of all register values.
The integrated values for active and
reactive energy as well as the mains
frequency and voltage information are
accessable through the serial interface as
16 bit values.
This universal single phase power/energy
metering integrated circuit is ideally suited
for energy calculations in applications such
as electricity dispensing systems (ED's),
residential municipal metering and factory
energy metering and control.
The SA9603C integrated circuit is available
in both 14 and 20 pin dual-in-line plastic
7133
sames
■
Adaptable to different current sensor
technologies
■
Operates over a wide temperature
range
■
Serial interface having a RS232
protocol
■
Precision voltage reference on-chip
Tri-state output to allow parallel
connection of devices
■
(DIP-14/DIP-20), as well as 20 pin small
outline (SOIC-20) package types.
PIN CONNECTIONS
IIN
1
14
GND
IIP
2
13
IVP
VR EF
3
12
T P12
T EST
4
11
FM O
VDD
5
10
V SS
OSC2
6
9
SIN
OSC1
7
8
SOUT
DR-01088
Package: DIP-14
1/18
1/16
PDS039-SA9603C-001
REV. A 19-09-97
SA9603C
PIN CONNECTIONS
IIN
1
20
GND
IVP
IIP
2
19
VREF
3
18
TP18
TP4
4
17
TP17
TP5
5
16
TP16
TP6
6
15
TEST
V DD
7
14
FMO
V SS
8
13
SIN
TP9
9
12
SOUT
OSC2 10
11 OSC1
D R-00829
Package: DIP-20
SOIC-20
BLOCK DIAGRAM
VDD
T E ST
IIP
A C TIV E
E N E R GY
IIN
R E A C TIV E
E N E R GY
ANALOG
V SS
S IN
SERIAL
FR E QU E N CY
SO U T
IN TER FACE
V OLTA GE
SIGNAL
FM O
PROCEVOLTAGE
REF.
SSING
IVP
GND
OSC
D R - 00830
2/18
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VR EF
O SC 1
TIMING
O SC 2
SA9603C
ABSOLUTE MAXIMUM RATINGS*
Parameter
Supply Voltage
Symbol
VDD -VSS
Min
-0.3
Max
6.0
Current on any pin
IPIN
-150
+150
Storage Temperature
TSTG
-40
+125
°C
TO
-10
+70
°C
Operating Temperature
Unit
V
mA
* 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 condition 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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3/18
SA9603C
ELECTRICAL CHARACTERISTICS
(VDD = 2.5V, VSS = -2.5V, over the temperature range -10°C to +70°C #, unless otherwise
specified.)
Parameter
Symbol Min
Typ
Max
Unit Condition
Supply Voltage: Positive
VDD
2.25
2.75
V
Supply Voltage: Negative
VSS
-2.75
-2.25
V
Supply Current: Positive
IDD
5
6
mA
Supply Current: Negative
ISS
5
6
mA
-25
+25
µA
Peak value
IIV
-25
+25
µA
Peak value
Pin FMO
Output Low Voltage
Output High Voltage
VOL
VOH
VSS+1
VDD-1
V
V
IOL = 5mA
IOH = -2mA
Pin SIN
Input High Voltage
Input Low Voltage
Pull-up Current
VIH
VIL
-II
V
V
µA
VIN = VSS
Current Sensor Inputs (Differential)
Input Current Range
III
Voltage Sensor Input (Asymetrical)
Input Current Range
VDD-1
VSS+1
150
50
Pin SOUT
Tri-state
Output Low Voltage
VOL
Output High Voltage
VOH
Oscillator
VDD-1
V
V
Recommended crystal:
TV colour burst crystal f = 3.5795 MHz
Pin VREF
Ref. Current
Ref. Voltage
#
VSS+1
-IR
VR
45
1.1
50
55
1.3
µA
V
Extended Operating Temperature Range available on request.
4/18
sames
With R = 24kΩ
connected to VSS
Referred to VSS
SA9603C
PIN DESCRIPTION
Description
Ground
14 Pin
14
20 Pin
20
Designation
GND
5
10
8
14
VDD
VSS
Positive Supply Voltage
Negative Supply Voltage
13
1
19
1
IVP
IIN
Analog input for mains voltage
Inputs for current sensor
2
7
2
11
IIP
OSC1
Connections for crystal or ceramic resonator
6
8
10
12
OSC2
SOUT
(OSC1 = Input ; OSC2 = Output)
Serial Interface Out
9
3
13
3
SIN
VREF
Serial Interface In
Connection for current setting resistor
4
11
7
15
TEST
FMO
Test Pin. Must be connected to VSS
Mains frequency zero-crossing indication
4
5
TP4
TP5
6
9
TP6
TP9
16
TP12
TP16
17
18
TP17
TP18
12
Test Pins (Leave unconnected)
FUNCTIONAL DESCRIPTION
The SA9603C is a CMOS mixed signal Analog/Digital integrated circuit, which performs
power/energy calculations across a power range of 1000:1, to an overall accurancy of
better than Class 1.
The integrated circuit includes all the required functions for 1-phase power and energy
measurement, such as two oversampling A/D converters for the voltage and current
sense inputs, power calculation and energy integration. Internal offsets are eliminated
through the use of cancellation procedures. The SA9603C integrates the measured
active and reactive power consumption into 22 bit integrators, which are accessable via
a serial port having a RS232 protocol. Two additional on-chip registers exist: one register
contains the mains frequency information; and the other the voltage information.
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SA9603C
1.
Power Calculation
In the Application Circuit (Figure 1), the voltage drop across the shunt will be
between 0 and 16mVRMS (0 to 80A through a shunt resistor of 200µΩ). This voltage
is converted to a current of between 0 and 16µARMS, by means of resistors R1 and
R2.
The current sense input saturates at an input current of ±25µA peak.
For the voltage sensor input, the mains voltage (230V AC) is divided down through
a divider to 14VRMS. The resulting current into the A/D converter input is 14µARMS
at nominal voltage, via resistor R4 (1MΩ).
In this configuration, with a mains voltage of 230V and a current of 80A, the
SA9603C functions at its optimum conditions, having a margin of 3dB for overload
available.
2.
Analog Input Configuration
The input circuitry of the current and voltage sensor inputs are illustrated below.
These inputs are protected against electrostatic discharge through clamping
diodes.
The feedback loops from the outputs of the amplifiers AI and AV generate virtual
shorts on the signal inputs. Exact duplications of the input currents are generated
for the analog signal processing circuitry.
V DD
IIP
CURRENT
S E N S OR
IN P U TS
VSS
AI
VD D
IIN
VS S
VD D
IV P
V O LTA G E
S E N S OR
IN P U T
D R -00831
6/18
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VSS
AV
GN D
SA9603C
3.
Electrostatic Discharge (ESD) Protection
The SA9603C integrated circuit's inputs/outputs are protected against ESD .
4.
Power Consumption
The power consumption rating of the SA9603C integrated circuit is less than
25mW.
5.
Serial Interface
Reading and resetting of the SA9603C's on-chip integrators, is performed via the
serial interface.
The settings are:
19 200 Baud
1 Start bit (S)
1 Stop bit (E)
No parity bits
The serial interface, having a RS232 protocol, has been designed to operate directly
with a PC (Personal Computer).
The serial interface allows for the following operations:
Read Integrator (RD): The SA9603C integrated circuit transmits the integrator
status to the controller, after the current measurement cycle has been completed
(8 mains periods maximum).
The register containing the mains frequency information is read only.
Reset Integrator (RES): The SA9603C integrator is reset, without transmitting the
integrator status.
Read/Reset Integrator (RD/RES): The SA9603C transmits the integrator status
and resets the integrator after the current measurement cycle has been completed.
In a typical application, the system controller monitors the status of the SA9603C's
integrator using the "Read" command. At rated load conditions, the capacity of the
22 bit integrator allows for an integration time of 2 seconds, prior to integrator
overflow.
If after a "Read" command, the integrator value is sufficently high, a "Read/Reset"
command from the controller causes the SA9603C integrated circuit to complete
the existing measurement cycle, transmit the most significant bits of the 22 bit
integrator via the Serial Output (SOUT) to the controller and restart the integrator.
In order to ensure correct measurements, the integrator commands ("Read" and
"Read/Reset") are only executed after completion of the internal offset calibration
cycle. The cycle length is 8 mains periods.
Thus, for power calculations, the time value should be taken from the difference in
time from the previously received energy value to the currently received value.
By adapting the "Read/Reset" rate to the line current, the accuracy of the
measurement can be achieved down to lowest signal levels.
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7/18
SA9603C
Dump register values: The content of the individual registers are transmitted
sequentially, at the 'Dump' command. Transmission of the first register value will
start with the completion of the current measurement cycle (Maximum 8 mains
cycles). The sequence of the registers is always as follows: Mains voltage, mains
frequency, reactive energy register followed by the active energy register value. By
specifying the register in the DUMP command, register values are transmitted
starting with the specified register and stopping with the active energy register.
Commands for the active energy integrator
RD
RD
RES
RES
RD
RD/
RES
RES
DUMP
D R -0 08 32
DUMP
START
BIT
STOP
BIT
Commands for the reactive energy integrator
RD
RD
RES
RES
RD
RD/
RES
DUM P
DR- 0 08 33
RES
DUM P
STA RT
BIT
STOP
BIT
Commands for the frequency register
RD
RD
DUMP
DUMP
START
BIT
DR-0083 4
8/18
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STOP
BIT
SA9603C
Commands for the voltage integrator
RD
RD
RES
RES
RD /
RES
RD
RES
D UM P
D UM P
S TO P
BIT
S TA RT
BIT
DR-01362
The register access codes which may be written to the SA9603C via the serial
communications port, are shown in the table below:
READ
$01
$81
$41
$C1
RESET
$02
$82
$C2
READ-RESET
$03
$83
$C3
DUMP
$05#
$84
$44
$C4
<
<
<
REGISTER
ACTIVE
RE-ACTIVE
FREQUENCY
VOLTAGE
#
Note: The Dump Active ($04) and Read Active ($01) commands have the same
effect.
Data on SOUT
8
9
10
F IR S T
11
12
13
B Y T E
14
15
0
1
2
3
S E C O N D
4
5
6
7
B Y T E
D R -0 0 8 3 5
From the two bytes of data output by the device, the value for the register can
be derived as shown:
Register value =
(First Byte * 256) + Second Byte
The register value is represented in two's compliment in order to provide for
positive and negative register values.
The most significant bit of the 16 bit energy register (active or reactive) may be
used as an indication of the direction of the energy flow (0 = positive, 1 =
negative).
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9/18
SA9603C
6.
Register Values
a.
The active and reactive energy measured per count, may be calculated by
applying the following formula:
V*I
Watt seconds
K
Rated Voltage
Rated Current
9281
for Active Energy
Energy per Count
Where
V
I
K
=
=
=
=
9281 * 2 for Reactive Energy
π
b.
The mains frequency may be calculated as follows:
Crystal frequency
Frequency =
Register Value * 8
c.
To calculate the measured voltage, the following formula may be used:
V*n
Vmeasured = 14000
*t
Where
7.
10/18
V
t
n
=
=
=
rated mains voltage
time difference between successive reads
difference in register values between
successive reads
Software Flow
The SA9603C is able to execute code written for the SA9103C without any
modifications. (Ensure that only bits of the serial command to the device is set that
need to be set.)
It is suggested that the DUMP command is used in cases where more than one
register is continuously read. The DUMP command initiates a serial transmission
of successive register values, starting with the specified register. The Dump
command does not reset the register values.
New software should be developed in such a way that registers are never resettled
and must allow for register overflow. Register overflow is easily taken into account
by software running on a controlling microcontroller. The software subtracts the
previous register value from the current register value in order to determine the
actual change in register value. Note that the mains frequency register value only
needs to be scaled, in order to calculate the true mains frequency in Hertz.
The SA9603C integrated circuit only transmits the register values after completion
of the current measurement cycle (8 mains periods maximum).
The delay of 8 mains periods may be calculated from the period value of the
frequency returned by the initial read, and updated with each subsequent frequency
reading.
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SA9603C
8.
Calibration
For calibration of the SA9603C, the following procedure is recommended:
a. Establish the calibration factor for active energy (Ka) at power factor (PF)
close to 1.
Active (Measured) = register_value (Active) * Ka.
1
b. The factor for reactive (Kr) is typically Ka * PI/2.
For higher accuracy of Kr, establish Kr at PF close to 0.
Reactive (Measured) = register_value (Reactive) * Kr
2
c. At PF close to 1, establish error for reactive (Er)
Er = (Reactive (Measured) - Reactive (True)) / Active (Measured)
3
Reactive (Corrected) = Reactive (Measured) - Er * Active (Measured)
3b
Measurement
Having determined the scaling factors (Ka & Kr) and error correction constant (Er)
the measurement cycle consists of the following steps:
Step 1
Read active register
Step 2
∨
Calculate Active (Measured) as per 1
Step 3
∨
Read reactive register
Step 4
∨
Calculate Reactive (Measured) as per 2
Step 5
∨
Perform error correction
Calculate Reactive (Corrected) as per 3b
⇒
Active energy
⇒
Reactive energy
The above five steps must be performed for each measurement cycle.
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11/18
SA9603C
TYPICAL APPLICATIONS
In the Application Circuits (Figures 1 and 2), the components required for power metering
applications, are shown.
In Figure 1, a shunt resistor is used for current sensing. In this application, the circuitry
requires a +2.5V, 0V, -2.5V DC supply.
In the case of Figure 2, when using a current transformer for current sensing, a +5V, 0V
DC supply is sufficient for the circuit.
R1, R2 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 SA9603C at rated
line current.
Values for RSH of less than 200µΩ should be avoided.
R1 = R2 = (IL/16µARMS) * RSH/2
Where IL
= Line current
RSH = Shunt resistor/termination resistor
R3, 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 14µARMS.
R7 defines all on-chip bias and reference currents. With R7 = 24kΩ, optimum conditions
are set.
XTAL is a colour burst TV crystal (f = 3.5795MHz) for the oscillator. The oscillator
frequency is divided down to 1.7897MHz on-chip to supply the A/D converters and digital
circuitry.
12/18
sames
L OA D
SUPPL Y
RS H
sames
D R -0 0 8 3 6
R5
C1 1
D2
D1
+
+
R1 0
C1 4
C1 3
R9
ZD2
ZD1
R7
IC-1
C9
C1 5
12
9
C1 0
XT AL
11
13
10
14
8
15
7
6
16
17
4
5
19
18
3
20
2
1
R4
R6
C1 2
3
2
1
R1 5
6
5
4
IC-3
IC-2
4
5
6
1
2
3
I S OL A T E D P C IN T E R F A C E
R1 4
R1 3
D3
R1 2
RT S
RX D
DS R
DT R
S E R IA L
INT E RF ACE
TXD
GN D
SA9603C
Figure 1: Application Circuit using a Shunt Resistor for current sensing,
having a PC (Personal Computer) Interface.
13/18
SA9603C
Part List for Application Circuit: Figure 1
Item
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
Symbol
IC-1
IC-2
IC-3
D1
D2
D3
ZD1
ZD2
XTAL
R1
R2
R3
R4
R5
R6
R7
R8
R9
R10
R11
R12
R13
R14
R15
C9
C10
C11
C12
C13
C14
C15
RSH
Description
SA9603C
Opto Coupler 4N35
Opto Coupler 4N35
Diode, Silicon, 1N4148
Diode, Silicon, 1N4148
Diode, Silicon, 1N4148
Diode, Zener, 2.4V, 200mW
Diode, Zener, 2.4V, 200mW
Crystal, 3.5795MHz
Resistor, 1% metal
Resistor, 1% metal
Resistor, 390k, (230VAC), 1% metal
Resistor, 1M, 1/4W, 1% metal
Resitor, 470Ω, 2W, 5%, carbon
Resistor, 24k, 1/4W, 1%, metal
Resistor, 24k, 1/4W, 1%, metal
Resistor, 680Ω, 1/4W, 5%
Resistor, 680Ω, 1/4W, 5%
Resistor, 680Ω, 1/4W, 5%
Resistor, 100k, 1/4W, 5%
Resistor, 120Ω, 1/4W, 5%
Resistor, 1/4W, 5%, 47k
Resistor, 1/4W, 5%, 1.6k
Resistor, 120Ω, 1/4W, 5%
Capacitor, 100nF
Capacitor, 100nF
Capacitor, 0.47µF, 250VAC, polyester
Capacitor, 100nF
Capacitor, 100µF
Capacitor, 100µF
Capacitor, 820nF
Shunt Resistor
Detail
DIP-20/SOIC-20
DIP-6
DIP-6
Colour burst TV
Note 1
Note 1
Note 2
Note 1: Resistor (R1 and R2) values are dependant upon the selected value of RSH.
Note 2: See TYPICAL APPLICATIONS when selecting the value for RSH.
14/18
sames
L
N
SUPPL Y
L OA D
D R -0 0 8 3 7
CT
5V
sames
R9
R8
R2
R3
C1 0
R7
RSH
R1
I C -1
10
9
7
8
5
6
C9
18
XTAL
11
13
12
15
14
17
16
3
4
2
20
19
1
R4
C1 1
R6
0V
S IN
S E RIA L INT E RF A CE
S OU T
FM 0
SA9603C
Figure 2: Application Circuit using a Current Transformer for current sensing.
15/18
SA9603C
Parts List for Application Circuit: Figure 2
Item
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Note 1:
Note 2:
Note 3:
Note 4:
Symbol
IC-1
XTAL
RSH
R1
R2
R3
R4
R6
R7
R8
R9
C9
C10
C11
CT
Description
SA9603C
Crystal, 3.5795MHz
Resistor
Resistor, 1%, metal
Resistor, 1%, metal
Resistor, 390k, (230VAC) 1%, metal
Resistor, 1M, 1/4W, metal
Resistor, 24k, 1/4W, metal
Resistor, 24k, 1/4W, metal
Resistor, 2.2k, 1/4W, 5%
Resistor, 2.2k, 1/4W, 5%
Capacitor, 820nF
Capacitor, 100nF
Capacitor
Current Transformer
Package
SA9603CPA
DIP-14
SA9603CPA
SA9603CSA
DIP-20
SOIC-20
16/18
Note 3
Note 4
See TYPICAL APPLICATIONS when selecting the value of RSH.
Resistor (R1and R2) values are dependant upon the selected value of
RSH.
Capacitor (C9) to be positioned as close to IC-1, as possible.
Capacitor (C11) selected for DC blocking and to minimize phase error
introduced by the current transformer.
Part Number
Note:
Detail
DIP-20/SOIC-20
Colour burst TV
Note 1
Note 2
Note 2
When ordering, the package option must be specified along with the part
number.
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SA9603C
Note:
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17/18
SA9603C
Disclaimer:
The information contained in this document is confidential and proprietary to South African MicroElectronic 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,
Koedoespoort Industrial Area,
0039
Pretoria,
Republic of South Africa,
Republic of South Africa
Tel:
Fax:
18/18
012 333-6021
012 333-8071
sames
Tel:
Fax:
Int +27 12 333-6021
Int +27 12 333-8071