sames
SA9105 APPLICATION NOTE
PM9105AF
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 PM9105AF 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 SA9105AF, SA9105EF or SA9105FF three phase
power metering integrated circuits for power measurement.
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PDS038-SA9105-001
Rev. B
13-09-95
PM9105AF
BLOCK DIAGRAM
ABSOLUTE MAXIMUM RATINGS *
Parameter
Symbol
Supply Voltage (Note 1)
VAC
Storage Temperature
TSTG
Operating Temperature (Note 2)
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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PM9105AF
ELECTRICAL CHARACTERISTICS
(Over the temperature range -10°C to +70°C, unless otherwise specified. Power
consumption figures are applicable to the PM9105AFE only.)
Parameter
Supply Voltage (x3 Phases)
(Continuous)
Frequency Output
Power Consumption1
Note 1:
Symbol Min Typ Max Unit Condition
VAC
180 230 265
V
PM9105AFE
90 115 138
V
PM9105AFA
FOUTX Refer to applicable IC data sheet
100 mW 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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PM9105AF
For rated conditions, the signals into the current and voltage sensor inputs are set
as follows:
Current sensor input currents:
Voltage sensor input currents:
16µ ARMS
14µ ARMS
Under these conditions, the device generates a pulse rate of 1,16kHz at output
FOUT1.
The output frequency at FOUT2 is FOUT1/4. At FOUT3 the output frequency is
FOUT1/290.
2.
Electrostatic Discharge (ESD) Protection
The device's inputs/outputs are protected against ESD according to 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 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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PM9105AF
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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PM9105AF
Figure 1: Connection Diagram
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PM9105AF
Figure 2: Application for Three Phase Power/Energy Measurement.
MAINS VOLTAGES
R1
R1A
R2
R2A
R3
R3A
PH1
PH2
PH3
N
0V
C4
34
24
44
12
11
10
13
9
14
8
5V
C9
R7
C5
C10
15
7
16
C6
17
R18
R8
CT1
18
R9
19
R19
R10
CT2
R11
R20
R12
CT3
6
SA9105
4
PLCC-44
20
21
R15
+ C1
R16
+ C2
R17
+ C3
5
3
R6
2
IC-1
2.5V
C7
22
43
23
42
25
41
26
40
27
39
C8
0V
XTAL
5V
R4
R21
C14
5V
P6
P5
C13
0V
28
38
29
37
FOUT3
32
36
FOUT2
33
35
FOUT1
30
31
C12
R5
C11
1
R13
2.5V
2.5V
0V
0V
0V
R14
DR-00882
P14
OV
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PM9105AF
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
SA9105AF/SA9105EF
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
PLCC-44
TV Crystal
Note 4
Note 4
Note 4
Note 4
Note 4
Note 4
Note
Note
Note
Note
Note
Note
1
1
1
1
1
1
Note 1
Note 1
Note 1
Multi
Multi
Multi
Note
Note
Note
turn
turn
turn
2
2
2
PM9105AF
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.
Item
Symbol
3
4
5
6
7
8
R1
R1A
R2
R2A
R3
R3A
Description
PM9105AFA
PM9105AFE
115V
230V
200kΩ
120kΩ
180kΩ
82kΩ
200kΩ
120kΩ
180kΩ
82kΩ
200kΩ
120kΩ
180kΩ
82kΩ
Detail
ORDERING INFORMATION
Part Number
PM9105AFA
PM9105AFE
Description
3 X 115V, 3 X 80A Module
3 X 230V, 3 X 80A Module
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PM9105AF
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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:
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012 333-6021
012 333-8071
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Tel:
Fax:
Int +27 12 333-6021
Int +27 12 333-8071