sames
SA9105 APPLICATION NOTE
PM9105AP
THREE PHASE POWER/ENERGY METERING MODULE
PULSE OUTPUT
FEATURES
n
Performs one, two or three phase power
and energy measurement
n
Uses current transformers for current
sensing
n
Meets the accuracy requirements for
Class 1 AC Watt hour meters
n
Three pulse rate outputs available
n
Protected agianst ESD
n
Operates over a wide Temperature
Range
DESCRIPTION
The SAMES three phase power/energy metering module, the PM9105AP provides three
pulse rate output options, the frequency of which are proportional to the active power
consumption.
Energy consumption can be 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 three phase power/energy metering circuit is
ideally suited for energy calculations in applications using a µ-controller or mechanical
counter.
The application utilises the SAMES SA9105APA, SA9105EPA or SA9105FPA three
phase power metering integrated circuits for power measurement.
The module is supplied configured to operate on 3 x 230V, 3 x 80A mains system. This
can be adapted to operate on 3 x 115V, 3 x 80A mains system. Please refer to the resistor
selection table shown at the end of the Application Circuit parts list.
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7184
PDS038-SA9105-002
Rev. A
07-01-97
PM9105AP
BLOCK DIAGRAM
ABSOLUTE MAXIMUM RATINGS *
Parameter
Symbol
Supply Voltage (Note 1)
VAC
Storage Temperature
Operating Temperature (Note 2)
TSTG
TO
Min
Max
Unit
-25
-10
540
+125
+70
V
°C
°C
Note 1:
Voltages are specified with reference to Neutral.
Note 2:
The SA9105 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.
* 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 operation sections of this
specification, is not implied. Exposure to Absolute Maximum Ratings for extended
periods may affect device reliability.
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PM9105AP
ELECTRICAL CHARACTERISTICS
(Over the temperature range -10°C to +70°C, unless otherwise specified.
Parameter
Supply Voltage (x3 Phases)
(Continuous)
Frequency Output
Power Consumption1
Note 1:
Symbol Min Typ Max Unit
VAC
180 230 265
V
FOUTX
Condition
PM9105APE
Refer to applicable IC data sheet
100 m W VDD = 5V
Power consumption specifications exclude power consumed by the current
sensors.
CONNECTION DESCRIPTION
Designation
Description
PL5
Voltage Supply connected to Phase 1
Voltage Supply connected to Phase 2
Voltage Supply connected to Phase 3
Voltage Supply connected to Neutral Line (Common)
PL6
Power Output: 4Hz at rated current
Power Output: 290 Hz at rated current
Power Output: 1160 Hz at rated current
0V (Common)
PL4
5V DC Supply Voltage
0V DC Supply Voltage
CT1
Phase 1 (Direction indicated on PCB)
CT2
Phase 2 (Direction indicated on PCB)
CT3
Phase 3 (Direction indicated on PCB)
FUNCTIONAL DESCRIPTION
1. Power Calculation
In the Application Circuit (see Figure 2), the output currents from the current sensors
will be between 0 and 16µA. The current input stages saturate at input currents
greater than 18µARMS. The mains voltage (mains voltage + 15% - 20%) is used for
the power calculation, together with the current information from the current sensors
(current transformers).
The calculated power for the 3 phases is integrated over time and converted into a
corresponding frequency.
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PM9105AP
For rated conditions, the signals into the current and voltage sensor inputs are set
as follows:
Current sensor input currents: 16µ A RMS
Voltage sensor input currents: 14µ A RMS
Under these conditions, the device generates a pulse rate of 1.16kHz at output
FOUT1.
2.
Electrostatic Discharge (ESD) Protection
The device's inputs/outputs are protected against ESD. 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 500mW, excluding the current sensors.
4.
Isolation
The reference for the unit is connected to neutral.
5.
Circuit Description
The module is supplied from an external 5V DC supply.
The Application Circuit (figure 2), details the components required for a three phase
power metering module. Terminated current transformers are used as current
sensors.
The most important external components are:
C7, C9, C 10 and C11 are the outer loop capacitors for the integrated oversampling
A/D converters. The typical value of C7 is 2.2nF and the value of C9, C10 and C 11 is
560pF.
The actual values determine the signal to noise and stability performance. The
tolerances should be within ± 10%.
C4, C5, C6 and C8 are the inner loop capacitors for the integrated oversampling
A/D converters. The typical value of C4, C5, C6 and C8 is 3.3nF. Values smaller than
0.5nF and larger than 5nF should be avoided.
Terminated current sensors (current transformers) are connected to the current
sensor inputs of the SA9105 through current setting resistors (R8 ..R 13).
The resistor values should be selected for an input current of 16µA into the SA9105
at the rated line current.
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PM9105AP
The values of these resistors should be calculated as follows:
Phase 1:
R8 = R9 = (IL1/16µA) x R18/2
Phase 2:
R10 = R11 = (I L2/16µA) x R19/2
Phase 3:
R12 = R13 = (I L3/16µA) x R20/2
Where ILX
=
Secondary CT current at rated conditions.
R18, R19 and R20 =
Termination resistors of the three current transformers.
R1 + R1A, R4 and R15 set the current for the phase 1 voltage sense input. R2 + R2A,
R5 + P5 and R16 set the current for phase 2 and R3 + R3A, R 6 + P6 and R17 set the current
for Phase 3. The values should be selected so that the input currents into the voltage
sense inputs (virtual ground) is set to 14µA at nominal line voltage. Capacitors C1,
C2 and C3 are for decoupling and phase compensation.
R14 + P14 defines all on-chip bias and reference currents. With R14 + P14 = 24kΩ,
optimum conditions are set. P14 may be varied within ± 10% for calibration purposes.
Any changes to R14 will affect the output quadratically (i.e: ∆R = +5%, ∆FOUT =
+10%).
XTAL is a colour burst TV crystal (f = 3.5795 MHz) for the oscillator. The oscillator
frequency is divided down to 1.7897 MHz on-chip to supply the digital circuitry and
the A/D converters.
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PM9105AP
Figure 1: Connection Diagram
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P L3
P L2
P L1
S
P L1
CT
2 -P IN
2 -P IN
2 -P IN
2 -P IN
0V
C 12
R 20
R 19
R 18
C 13
D R -0 1 30 2
R 13
R 12
R 11
R 10
R9
R8
0V
P 14
R 14
19
11
10
9
8
7
6
14
4
15
5
2
40
1
VDD
OS C1
IIP 3
IIN 3
IIP 2
IIN 2
IIP 1
C IP P
IIN 1
C IP 3
C IN P
C IP 2
C IN 3
C IP 1
C IN 2
C IN 1
28
19 O S C 2
C8
C8
C6
C5
3
C4
VREF
29
S A 9 1 1 0 5 AP A
0V
VS S
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16
GND
35
FO U T1
FO U T2
FO U T3
TP 17
TP 18
TP 24
TP 25
TP 26
TP 27
IVP 3
IVP 2
COP P
IVP 1
COP 3
CONP
COP 2
CON3
COP 1
CON2
CON1
23
17
22
21
32
33
34
12
31
13
27
25
26
C7
C 11
30
36
18
24
C9
C 10
37
39
38
R 17
R 16
R 15
C 14
0V
R3
+C 1
R 3A
5V
+C 2
+C 3
R 21
R7
P 14
R 2A
R2
0V
P 14
R 1A
R1
0V
0V
P L5
M AI NS
V O L T AG E
P L5
4 -P IN
IC - 1
+ 5V S UP P L Y
PM9105AP
Figure 2: Application for Three Phase Power/Energy Measurement.
4 -P IN
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XT A L
PM9105AP
Parts List for Application Circuit: Figure 2
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
33
34
35
36
37
38
39
40
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Symbol
IC-1
XTAL
R1
R1A
R2
R2A
R3
R3A
R4
R5
R6
R7
R8
R9
R10
R11
R12
R13
R14
R15
R16
R17
R18
R19
R20
R21
P5
P6
P14
C1
C2
C3
C4
C5
C6
C7
C8
C9
C10
C11
Description
SA9105APA/SA9105EPA/SA9105FPA
Crystal, 3.5795 MHz
Resistor, 1%, ¼W, Metal
Resistor, 1%, ¼W, Metal
Resistor, 1%, ¼W, Metal
Resistor, 1%, ¼W, Metal
Resistor, 1%, ¼W, Metal
Resistor, 1%, ¼W, Metal
Resistor, 24k, 1%, ¼W, Metal
Resistor, 22k, 1%, ¼W, Metal
Resistor, 22k, 1%, ¼W, Metal
Resistor, 820Ω, 1%, ¼W, Metal
Resistor, 2.7k, 1%, ¼W, Metal
Resistor, 2.7k, 1%, ¼W, Metal
Resistor, 2.7k, 1%, ¼W, Metal
Resistor, 2.7k, 1%, ¼W, Metal
Resistor, 2.7k, 1%, ¼W, Metal
Resistor, 2.7k, 1%, ¼W, Metal
Resistor, 22k, 1%, ¼W, Metal
Resistor, 1M, 1%, ¼W, Metal
Resistor, 1M, 1%, ¼W, Metal
Resistor, 1M, 1%, ¼W, Metal
Resistor, 2.7Ω, 1%, ¼W, Metal
Resistor, 2.7Ω, 1%, ¼W, Metal
Resistor, 2.7Ω, 1%, ¼W, Metal
Resistor, 820Ω, 1%, ¼W, Metal
Potentiometer, 4.7k
Potentiometer, 4.7k
Potentiometer, 4.7k
Capacitor, electrolytic, 1µF, 16V
Capacitor, electrolytic, 1µF, 16V
Capacitor, electrolytic, 1µF, 16V
Capacitor, ceramic, 3.3nF
Capacitor, ceramic, 3.3nF
Capacitor, ceramic, 3.3nF
Capacitor, ceramic, 2.2nF
Capacitor, ceramic, 3.3nF
Capacitor, ceramic, 560pF
Capacitor, ceramic, 560pF
Capacitor, ceramic, 560pF
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Detail
DIP-40
TV Crystal
Note 4
Note 4
Note 4
Note 4
Note 4
Note 4
Note 1
Note 1
Note 1
Note 1
Note 1
Note 1
Note 1
Note 1
Note 1
Multi turn
Multi turn
Multi turn
Note 2
Note 2
Note 2
PM9105AP
Parts List for Application Circuit: Figure 2 (Continued)
Item
41
42
43
Symbol
C12
C13
C14
Description
Capacitor, ceramic, 100nF
Capacitor, ceramic, 820nF
Capacitor, ceramic, 100nF
Detail
Note 3
Note 1: Resistor (R8, R9, R10, R11, R12 and R13) values are dependant upon the selected
values of the current transformer termination resistors R18, R19 and R20.
Note 2: Capacitor values may be selected to compensate for phase errors caused by the
current transformers
Note 3: Capacitor (C13) to be positioned as close to Supply Pins (VDD & VSS) of IC-1, as
possible.
Note 4: See the table below detailing the component values for the selected voltage
standard.
*
Description
Item
Symbol
Detail
230V
115V *
3
R1
200kΩ
120kΩ
4
R1A
180kΩ
82kΩ
5
R2
200kΩ
120kΩ
6
R2A
180kΩ
82kΩ
7
R3
200kΩ
120kΩ
8
R3A
180kΩ
82kΩ
If module is required for 115V operation, the resistors in the above table must be
changed to the values shown.
ORDERING INFORMATION
Part Number
PM9105AP
Description
3 X 230V, 3 X 80A Module
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PM9105AP
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.
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
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
Tel:
Fax:
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