CS11-L Current Transformer
12/13
Copyright © 2001-2013
Campbell Scientific, Inc.
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Table of Contents
PDF viewers: These page numbers refer to the printed version of this document. Use the
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1. General Description....................................................1
2. Specifications .............................................................1
3. Installation...................................................................2
4. Wiring........................................................................... 3
5. ACPower Instruction ..................................................3
5.1 Using the ACPower Instruction with the CS11-L ................................3
5.2 ACPower (from CRBasic Help)...........................................................4
6. Programming ............................................................10
6.1 CR800, CR850, CR1000, or CR3000 Programming .........................11
6.1.1 Example CR1000 Program .........................................................12
6.2 CR200X-series Dataloggers ...............................................................12
6.2.1 CR200(X) Program for 60 Hz.....................................................13
6.2.2 CR200(X) Program for 50 Hz.....................................................14
6.3 CR510, CR10X, CR23X Dataloggers................................................14
6.3.1 Example CR10X Program ..........................................................15
6.4 21X, CR7 Dataloggers .......................................................................16
6.4.1 Example CR21X Program ..........................................................17
6.5 CR1000 with Multiplexer Sample Program .......................................18
6.5.1 Example CR1000 program reading 32 CS11-L Current
Tranformers.............................................................................18
6.6 CR10X with Multiplexer Sample Program ........................................18
6.6.1 Example CR10X program reading 32 CS11-L Current
Transformers ...........................................................................19
Appendix
A.
Theory of Operation................................................ A-1
A.1 Typical Electrical Circuit ................................................................ A-1
A.2 Current Transformer Description.................................................... A-2
A.3 Converting a Milliamp Signal to a Millivolt Signal ........................ A-3
A.4 Multiplier ........................................................................................ A-4
A.5 CS11-L Details................................................................................ A-4
A.6 Multiple Passes Through the Sensor ............................................... A-5
i
Table of Contents
Figures
1-1. CS11-L Current Transformer .............................................................. 1
3-1. AC load wire installed in CS11-L (color of ac load wire can vary) .... 2
4-1. CS11-L schematic ............................................................................... 3
5-1. ACPower Configuration 1................................................................... 5
5-2. ACPower Configuration 2................................................................... 6
5-3. ACPower Configuration 3................................................................... 7
6-1. Graph of a CS11-L waveform ........................................................... 13
6-2. Graph of CS11-L waveform using burst mode.................................. 15
6-3. Graph of a CS11-L waveform using 90 samples of amperage .......... 16
A-1. Generator schematic........................................................................ A-1
A-2. Schematic of generator with current transformer ............................ A-1
A-3. Schematic of current transformer with the wire ..............................A-2
A-4. CS11-L with the wire ...................................................................... A-2
A-5. Magnetic flux schematic.................................................................. A-2
A-6. Windings schematic......................................................................... A-3
A-7. CS11-L schematic ........................................................................... A-4
A-8. Adding 1250 mV creates positive output ........................................ A-5
A-9. CS11-L measurement range ............................................................ A-5
A-10. CS11-L with a wire making two passes through the sensor............ A-6
Table
6-1. Max Amps on Each of the Range Codes in the Datalogger (one
pass only). ...................................................................................... 11
ii
CS11-L Current Transformer
1. General Description
Campbell Scientific’s CS11-L (FIGURE 1-1) detects and measures the AC
current along an electrical wire using the magnetic field that is generated by
that current. The CS11-L does not have direct electrical connection to the
system. The sensor outputs a millivolt signal allowing it to be directly
connected to our dataloggers.
The CS11-L is compatible with our CR200X, CR800, CR850, CR1000,
CR3000, CR500, CR510, CR10(X),CR21X, and CR23X dataloggers. It uses
CR Magnetic’s CR8459 Current Transducer to measure the approximate
current over a range of 0 to 200 A.
The CS11-L has been developed in such a way that it can be used on most of
the datalogger models past and present, including the CR200(X). However, the
CR200(X) datalogger requires slightly different wiring than the other
dataloggers and requires derating of the maximum amperage to 125 amps.
FIGURE 1-1. CS11-L Current Transformer
2. Specifications
Example Applications:
• Motor or generator load conditions
• Efficiency studies
• Intermittent fault detection
• Submetering
1
CS11-L Current Transformer
Measurement Ranges: 0.15 to 200 A (0.15 to 125 A for CR200X)
Frequency: 50 and 60 Hz
Insulation Resistance: 100 M ohm @ 500 Vdc
High Potential: 2000 volts
Rated Current: 200 A, 125 A (CR200X)
Storage Temperature: –25º to 70ºC
Operating Temperature: –25º to 55ºC
Case Material: Polypropylene Resin
Construction: Epoxy Encapsulated
Accuracy with 10 ohm
Burden Max. (resistive): Typically ±1 percent of actual value with
provided multiplier
3. Installation
Dimensions
Outer Diameter: 4.8 cm (1.89 in)
Inner Diameter: 1.9 cm (0.75 in)
Height: 1.7 cm (0.67 in)
Multiplier: i
Place one AC wire through the hole of the CS11-L (see FIGURE 3-1). The
sensor may be placed on either the hot or neutral AC wire.
Mult
=200 A/1000mV=0.2
2
FIGURE 3-1. AC load wire installed in CS11-L (color of ac load wire
can vary)
4. Wiring
CS11-L Current Transformer
The CS11-L uses a single-ended analog channel as follows:
Wire Color Terminal
RED
or AG (VX on CR200X)
WHITE SE
BLACK
Shield
or AG
or AG
CS11-L
Cable
WHITE
RED
BLACK
CLEAR
FIGURE 4-1. CS11-L schematic
If multiple wire passes are needed, see the end of the first paragraph in
Appendix A.6, Multiple Passes Through the Sensor.
5. ACPower Instruction
5.1 Using the ACPower Instruction with the CS11-L
The CS11-L can be measured by programming the datalogger using the
ACPower Instruction (found in the CR8X0, CR1000, CR3000 dataloggers).
The ACPower instruction is designed to measure the voltage, frequency and
amperage of an AC load, then calculate the phase angle, harmonic distortion of
both the voltage and the current, as well as the real power of the load. In order
to obtain all of these measurements and values, another sensor, a potential
transformer, is required in addition to the CS11-L sensor. The datalogger will
measure voltage signal and frequency of the potential transformer. It will also
measure the current of the CS11-L.
1250 mV offset
Wire Color
WHITE
RED
BLACK
CLEAR
CR200X
Datalogger
SE
VX (EX)
All Other
Dataloggers
SE
3
CS11-L Current Transformer
'CR1000 Series Datalogger
' CS11-L_with_ACPower_AmpsOnly.CR1
'date: June 24, 2013
'
' Wiring:
' SE2 White CS11-L
' AG Black CS11-L
' AG Clear CS11-L
' AG Red CS11-L
PipeLineMode ' must be pipeline mode
Public Batt_volt
Public Amp_Mult
Public Amperage
Dim Array1(10)
PreserveVariables ' to store values between power cycles
DataTable (AmpTable,True,-1)
DataInterval (0,1,Min,10)
Average (1,Amperage,FP2,False)
Maximum (1,Amperage,FP2,False,False)
EndTable
BeginProg
Amp_Mult = 200/1000 ' 0.2 multiplier for the CS11-L (200Amps/1000mV=0.2)
Scan (500,mSec,0,0)
Battery (Batt_volt)
ACPower (Array1(),1,60,1,0.345345,120,2,.2,200,1)
Amperage=Array1(4)
' If Amperage <= 0.15 Then Amperage = 0
CallTable (AmpTable)
NextScan
EndProg
If no potential transformer will be used, the CS11-L and the ACPower
instruction will give you amperage, but not the other values, so you should
ignore all of the other values returned from the ACPower instruction. Most of
these other values will show up as NAN (not a number) when no potential
transformer is used.
5.2 ACPower (from CRBasic Help)
The ACPower instruction measures real AC power and a number of power
quality parameters for single-phase, split-phase, and three-phase ‘Y’
configurations.
Syntax
ACPower ( DestAC, ConfigAC, LineFrq, ChanV, VMult, MaxVrms, ChanI,
IMult, MaxIrms, RepsI )
The ACPower instruction is suitable for net-metering applications, as well as
variable-frequency (wild AC) applications. Potential and current transformers
must be used to measure the voltage and current using the datalogger.
4
CS11-L Current Transformer
WARNING
Working with live electrical equipment is dangerous!
The user is responsible for ensuring all wiring
conforms to local safety regulations and that the
enclosure is labeled accordingly.
DestAC The DestAC parameter is a variable or variable array in
which to store the measurement results. The number of
values returned depends upon the option chosen for the
configuration parameter. If DestAC is not dimensioned large
enough to hold all values, only those values that will fit into
the array will be stored.
ConfigAC The ConfigAC parameter is used to determine the type of
measurement that will be made.
Option Description
1 Single-phase with one voltage measurement and the number
of current measurements specified by the RepsI parameter.
This configuration monitors a single load with one voltage
and one current measurement, or multiple loads in sub-panel
applications with one voltage and multiple current
measurements. See FIGURE 5-1.
FIGURE 5-1. ACPower Configuration 1
5
CS11-L Current Transformer
Option Description
2 Split-phase with one voltage measurement and two current
measurements. This configuration is typical of residential
service-entry panels, as well as residential and commercial
distribution panels. Split-phase configurations have two line
(or “hot”) conductors plus a neutral conductor. See
FIGURE 5-2.
6
FIGURE 5-2. ACPower Configuration 2
CS11-L Current Transformer
Option Description
3 Three-phase ‘Y’, four-conductor, configurations with three
voltage measurements and three current measurements. This
configuration is typical of commercial entry panels and
commercial distribution panels. The four conductors are
three line (or “hot”) conductors plus a neutral conductor.
See FIGURE 5-3.
FIGURE 5-3. ACPower Configuration 3
LineFrq The LineFrq parameter is the expected line frequency in
hertz. Valid entries are 60, 50, or a value between 2 and 20.
A value between 2 and 20 indicates measurements from
variable-frequency power, where LineFrq is the minimum
frequency to be measured. Note that smaller values for
LineFrq increase the measurement and processing time for
this instruction.
ChanV The ChanV parameter is the single-ended channel for the
voltage measurement. For single- and split-phase
configurations (ConfigAC = 1 or 2), the datalogger makes a
voltage measurement at ChanV. For three-phase
configurations (ConfigAC = 3), the datalogger makes three
voltage measurements on increasing consecutive channels
starting at ChanV.
VMult The VMult parameter is the potential transformer multiplier
represented as input volts per output mV. A typical value is
115 V/333 mV (or 0.345345).
7
CS11-L Current Transformer
MaxVrms The MaxVrms parameter is the expected maximum rms
(root mean square) voltage to measure. MaxVrms is
specified at the primary of the potential transformer, or
equivalently, the non-datalogger side of the potential
transformer. Typical values are 120 or 240. The datalogger
uses VMult and MaxVrms to calculate which input range to
use for the voltage measurement.
ChanI The ChanI parameter is the single-ended channel for the
current measurement. For single-phase configurations
(ConfigAC = 1) with RepsI greater than 1, the datalogger
makes multiple current measurements on increasing
consecutive channels starting at ChanI. For split-phase
configurations (ConfigAC = 2), the datalogger makes two
current measurements on increasing consecutive channels
starting at ChanI. For three-phase configurations
(ConfigAC = 3), the datalogger makes three current
measurements on increasing consecutive channels starting at
ChanV.
IMult The IMult parameter is the current transformer multiplier as
input amps per output mV. A typical value is 15 amps/333
mV (or 0.045045).
MaxIrms The MaxIrms parameter is the expected maximum rms
current to measure. MaxIrms is specified at the primary of
the current transformer, or equivalently, the non-datalogger
side of the current transformer. The datalogger uses Imult
and MaxIrms to calculate which input range to use for the
current measurement(s).
RepsI The RepsI parameter is the number of current measurements
to make on consecutive single-ended input channels. This
parameter is used only in configuration 1 and is ignored by
the datalogger for configurations 2 and 3.
Results Returned
In each of the three configurations, DestAC may be a single-element variable
or a dimensioned variable array. The ACPower instruction will store as many
results as will fit in DestAC.
If the LineFrq value is between 2 and 20, inclusive, (for example, the expected
frequency is not known or “wild”), the phase (VPhaseI) and harmonic ratio
(VHarmRatio) will not be included in the results.
ConfigAC = 1 Returns a maximum of 3 + 4•RepsI values in the following
order:
Power(RepsI). The real power in Watts measured by the
voltage and each current measurement, repeated to give
RepsI values.
MeasFrq. The measured voltage frequency in Hz.
Voltage. The measured voltage in Volts rms.
8
CS11-L Current Transformer
Current(RepsI). The measured current in amps rms,
repeated to give RepsI values.
VPhaseI(RepsI). The measured phase angle in radians that
the voltage leads the current, repeated to give RepsI values.
The cosine of VPhaseI is the power factor.
VHarmRatio. The measured voltage harmonic distortion
ratio given as the total harmonic content divided by the
fundamental content at LineFrq Hz. VHarmRatio is unitless.
IHarmRatio(RepsI). The measured current harmonic
distortion ratio given as the total harmonic content divided
by the fundamental content at LineFrq Hz, repeated to give
RepsI values. IHarmRatio is unitless.
ConfigAC = 2 Returns a maximum of 12 values in the following order:
TotPower. The total real power in watts.
Power(2). The real power in watts measured by the voltage
and each of two current measurements.
MeasFrq. The measured voltage frequency in Hz.
Voltage. The measured voltage in volts rms.
Current(2). The measured current in amps rms, repeated to
give two values.
VPhaseI(2). The measured phase angle in radians that the
voltage leads the current, repeated to give two values. The
cosine of VPhaseI is the power factor.
VHarmRatio. The measured voltage harmonic distortion
ratio given as the total harmonic content divided by the
fundamental content at LineFrq Hz. VHarmRatio is unitless.
HarmRatio(2). The measured current harmonic distortion
ratio given as the total harmonic content divided by the
fundamental content at LineFrq Hz, repeated to give two
values. IHarmRatio is unitless.
ConfigAC = 3 Returns a maximum of 20 values in the following order:
TotPower. The total real power in watts.
Power(3). The real power in watts measured for each of the
three line conductors.
MeasFrq. The measured voltage frequency in Hz.
Voltage(3). The measured voltage in volts rms for each of
the three line conductors.
9
CS11-L Current Transformer
6. Programming
Current(3). The measured current in Amps rms for each of
the three line conductors.
VphaseI(3). The measured phase angle in radians that the
voltage leads the current for each of the three line
conductors. The cosine of VphaseI is the power factor.
VHarmRatio(3). The measured voltage harmonic distortion
ratio given as the total harmonic content divided by the
fundamental content at LineFrq Hz for each of the three line
conductors. VHarmRatio is unitless.
IHarmRatio(3). The measured current harmonic distortion
ratio given as the total harmonic content divided by the
fundamental content at LineFrq Hz for each of the three line
conductors. IHarmRatio is unitless.
NOTE
SCWin users: This manual was written primarily for those whose
needs are not met by SCWin. Your procedure is much simpler:
just add the CS11-L (in the Miscellaneous Sensors folder), save
your program, and follow the wiring shown in Step 2 of SCWin.
The datalogger is programmed using either CRBasic or Edlog. Dataloggers
that use CRBasic include our CR200(X)-series, CR800, CR850, CR1000, and
CR3000. Dataloggers that use Edlog include our CR500, CR510, CR10(X),
CR21X and CR23X. In CRBasic, the VoltSE instruction is used to measure
the sensor. In Edlog, a P1 instruction is used.
In order to monitor the amperage of an alternating current circuit, the program
must take many samples from the CS11-L sensor to capture the waveform over
a specified time, and then calculate the average energy under the curve. There
are many methods to do this, depending on the datalogger, the untapped
programming capacity, and other factors.
TABLE 6-1 shows the maximum amperage for each datalogger, depending on
the range code.
10
CS11-L Current Transformer
TABLE 6-1. Max Amps on Each of the Range Codes in the Datalogger (one pass only).
Datalogger >>>
Range Codes
(mV)
CR200(X)
Series
CR10X
CR500
CR510
CR1000
CR800
CR850
CR21X CR23X CR3000
Amperage
Resolution
2.5 0.5 0.5 0.000133
5 1 0.000067
7.5 1.5 1.5 0.000400
10 2 0.000133
15 3 0.000200
20 4 0.000134
25 5 5 0.001334
50 10 10 10 0.000666
200 40 40 0.002660
250 50 50 0.013340
500 100 0.006660
1000 200 200 0.013320
2500 125 200 200 0.133400
5000 200 200 200 200 0.066600
6.1 CR800, CR850, CR1000, or CR3000 Programming
With these dataloggers, the best method for monitoring amperage is to make
millivolt burst measurements, and then calculate rms. The millivolt burst
measurements are made by using the VoltSE instruction with multiple reps on
the same channel (for example, negative value for channel number). The
SpaDevSpa instruction calculates rms.
NOTE
CAUTION
Program must be run in the pipeline mode on CRBasic
dataloggers.
It is important to measure complete cycles. If 100 measurements are taken
during a 0.1 second time period, the result will be five complete cycles for a 50
Hz waveform or six complete cycles for a 60 Hz waveform.
Do not average the waveform reading in the data table nor
use the 60 Hz or 50 Hz noise rejection in the measurement
instructions in the program. Doing so would result in an
incorrect zero amperage reading.
11
CS11-L Current Transformer
6.1.1 Example CR1000 Program
'CR1000 Series Datalogger
' CS11-L_with_ACPower_Instruction.CR1
'date: June 12, 2013
'
' Wiring:
' SE1 PT Potential Transformer Signal
' AG PT reference
' SE2 White CS11-L
' AG Black CS11-L
' AG Clear CS11-L
' AG Red CS11-L
PipeLineMode ' must be pipeline mode
Public Batt_volt
Public Amp_Mult
Public Array1(10)
Alias Array1(1) = Real_Power
Alias Array1(2) = Frequency
Alias Array1(3) = Voltage
Alias Array1(4) = Amperage
Alias Array1(5) = Phase_Angle
Alias Array1(6) = V_Harm_Ratio
Alias Array1(7) = I_Harm_Ratio
PreserveVariables ' to store values between power cycles
DataTable (AmpTable,True,-1)
DataInterval (0,1,Min,10)
Totalize (1,Real_Power,IEEE4,False)
Average (1,Frequency,FP2,False)
Average (1,Voltage,FP2,False)
Average (1,Amperage,FP2,False)
Maximum (1,Phase_Angle,FP2,False,False)
Maximum (1,V_Harm_Ratio,FP2,False,False)
Maximum (1,I_Harm_Ratio,FP2,False,False)
EndTable
BeginProg
Amp_mult = 0.2 ' 0.2 multiplier for the CS11-L (200Amps/1000mV=0.2)
Scan (500,mSec,0,0)
Battery (Batt_volt)
ACPower (Array1(),1,60,1,0.345345,120,2,.2,200,1)
CallTable (AmpTable)
NextScan
EndProg
Below is an example CR1000 program. In the program, a multiplier of 0.2 is
applied to the rms value; see Appendix A.4, Multiplier, for more information.
12
6.2 CR200X-series Dataloggers
The CS11-L is compatible with the CR200X-series dataloggers, with slightly
different wiring. The RED wire is connected to a VX terminal and requires an
ExciteV instruction in the program. The voltage excitation creates a positive
reference output that the CR200X-series can measure.
The recommended programming method for CR200X-series dataloggers
(where the scan interval is limited to once per second) is to place the VoltSE
instruction within a loop. The first CR200X example program has a loop that
CS11-L Current Transformer
r
V
samples 25 times, and the second CR200X example program has a loop that
samples 30 times. A 25-sample loop produces almost two cycles of a 60 Hz
waveform, and a 30-sample loop produces almost two cycles of a 50 Hz
waveform (see FIGURE 6-1). The average energy under the curve is
calculated using the RMSSpa instruction. A multiplier of 0.2 is applied to the
rms value; see Appendix A.4, Multiplier, for more information.
25 Samples of Amperage on CR200X Datalogger (60 Hz)
or 30 Samples of Amperage on CR200X Datalogger (50 Hz)
25 samples of Amperage on CR200 datalogge
80
60
40
20
m
0
135 7 9 11 13 15 17 19 21 23 25
-20
-40
-60
-80
Instanteneous Amps
CS11-L waveform
FIGURE 6-1. Graph of a CS11-L waveform
6.2.1 CR200(X) Program for 60 Hz
'CR200 Series Datalogger
' Program name: CS11-LManual60Hz.cr2
'date: Jun 2013
Const Samples = 25 ' 25 samples for 2 waves of 60 Hz.
'Const Samples = 30 ' 30 samples for 2 waves of 50 Hz.
Public Crnt_A
Public mV(Samples)
Dim Counter
DataTable (Amp,1,-1)
DataInterval (0,1,min)
Average (1,Crnt_A,False)
Maximum (1,Crnt_A,False,0)
EndTable
BeginProg
Scan (1,Sec)
ExciteV (Ex1,mV2500)
For Counter = 1 To Samples
VoltSe (mV(Counter),1,1,1.0,-1250)
Next
ExciteV (Ex1,mV0)
RMSSpa (Crnt_A,(Samples-0),mV(1))
Crnt_A=Crnt_A*0.2 ' Multiplier for sensor
If Crnt_A<0.15 Then ' Eliminate noise below 0.15 amps.
Crnt_A = 0
13
CS11-L Current Transformer
EndIf
CallTable Amp
NextScan
EndProg
6.2.2 CR200(X) Program for 50 Hz
'CR200 Series Datalogger
' Program name: CS11-LManual50Hz.cr2
'date: Jun 2013
Const Samples = 30 ' 25 samples for 2 waves of 60 Hz, and 30 samples for 2 waves
of 50 Hz.
Public Crnt_A
Public mV(Samples)
Dim Counter
DataTable (Amps,1,-1)
DataInterval (0,1,min)
Average (1,Crnt_A,False)
Maximum (1,Crnt_A,False,0)
EndTable
BeginProg
Scan (1,Sec)
ExciteV (Ex1,mV2500)
For Counter = 1 To Samples
VoltSe (mV(Counter),1,1,1.0,-1250)
Next
ExciteV (Ex1,mV0)
RMSSpa (Crnt_A,(Samples-0),mV(1))
Crnt_A=Crnt_A*0.2 ' Multiplier for sensor
CallTable Amps
NextScan
EndProg
14
6.3 CR510, CR10X, CR23X Dataloggers
With these dataloggers, the best method for monitoring amperage is to make
millivolt burst measurements using Instruction 23 and then calculate rms
using Instruction 82. For Instruction 23, the entry for parameter 4 needs to
be 0001. This triggers on the first channel, triggers immediately, stores data in
input locations, and makes single-ended measurements.
Remember that it is important to measure complete cycles. For Instruction
23, if parameters 5 and 6 are 2.0 and 0.05, respectively, you get five complete
cycles for a 50 Hz waveform, and six complete cycles for a 60-Hz waveform
(see FIGURE 6-2). The multiplier for the CS11-L is 0.2; see Appendix A.4,
Multiplier, for more information.
CS11-L Current Transformer
Six Cycles at 60 Hz Burst CR10X
I Instanteneous
FIGURE 6-2. Graph of CS11-L waveform using burst mode
The following CR10X program generates the waveforms shown in FIGURE
6-2.
NOTE
The instructions listed below do not store data in final storage.
P92, P77, and output processing instructions such as P70 are
required to store the data permanently.
6.3.1 Example CR10X Program
; Parameter 2 should be 2500 mV for 50-200 amps
; should be 250 mV for 5-49 amps
; should be 25 mV for 0-4.9 amps
; Parameter 5 should be 2.0 msec for 50 Hz or 60 Hz
; Parameter 6 should be 0.05 thousand scans for 50 Hz or 60 Hz
; if parameter 5 & 6 are 2.0 and 0.05, then you have 5 complete cycles at 50 Hz
; or 6 complete cycles at 60 Hz.
;
1: Burst Measurement (P23)
1: 1 Input Channels per Scan ; Should always be 1
2: 15 2500 mV Fast Range ; Change according to expected Amperage
3: 1 In Chan ; Change according to Wiring
4: 0001 Trig/Trig/Dest/Meas Options ; Should always be 0001
5: 2.0 Time per Scan (msec) ; Must be 2.0
6: .05 Scans (in thousands) ; Must be 0.05 (for 50 measurements • 2.0 msec = 100 mS)
7: 0 Samples before Trigger ; Should always be 0
8: 0.0 mV Limit ; Should always be 0
9: 0000 mV Excitation ; Should always be 0
10: 4 Loc [ Amps_1 ] ; First location of Block (array)
11: .2 Multiplier ; Match Multiplier of CT:0.2 for CS11-L with 10 ohm shunt
12: 0.0 Offset
2: Z=F x 10^n (P30)
1: 0.0 F
2: 00 n, Exponent of 10
3: 1 Z Loc [ Counter ]
; This part of the program will calculate the rms Amperage
; Standard Deviation in this part of the code works mathematically the same
; as rmscalculation, and it is easier to program this way. The rms
; value is calculated and stored back into an input location for further
; processing if needed.
15
CS11-L Current Transformer
3: Beginning of Loop (P87)
1: 0 Delay
2: 50 Loop Count
4: Z=Z+1 (P32)
1: 1 Z Loc [ Counter ]
5: If (X<=>F) (P89)
1: 1 X Loc [ Counter ]
2: 1 =
3: 50 F
4: 10 Set Output Flag High (Flag 0)
6: Set Active Storage Area (P80)
1: 3 Input Storage Area
2: 2 Loc [ BurstAmps ]
7: Standard Deviation (P82)^3012
1: 1 Reps
2: 4 -- Sample Loc [ Amps_1 ]
8: End (P95)
6.4 21X, CR7 Dataloggers
Some Edlog dataloggers such as the 21X and CR7 do not have a burst mode.
For those dataloggers, you can use a “Loop Measurement Method” similar to
the method used with the CR200X. This method is also an option for our
CR510, CR10X, and CR23X, but only three measurements per period will be
made. FIGURE 6-3 shows a graph produced by a CR10X program with a loop
that samples 90 times. A portion of this program is shown below.
FIGURE 6-3. Graph of a CS11-L waveform using 90 samples of
amperage
16
CS11-L Current Transformer
NOTE
The instructions listed below do not store data in final storage.
P92, P77, and output processing instructions such as P70 are
required to store the data permanently.
6.4.1 Example CR21X Program
3: Z=F (P30)
1: 0.0 F
2: 4 Z Loc [ Counter ]
4: Beginning of Loop (P87)
1: 0000 Delay
2: 90 Loop Count
5: Z=Z+1 (P32)
1: 4 Z Loc [ Counter ]
6: Volt (SE) (P1)
1: 1 Reps
2: 14 500 mV Fast Range
3: 1 SE Channel
4: 57 -- Loc [ LoopAmp_1 ] ; Use F4 to get indexing - 5: .2 Multiplier
6: 0.0 Offset
7: If (X<=>F) (P89)
1: 4 X Loc [ Counter ]
2: 1 =
3: 90 F
4: 10 Set Output Flag High
8: Z=X (P31)
1: 57 -- X Loc [ LoopAmp_1 ] ; Use F4 to get indexing - 2: 3 Z Loc [ Sensor ]
9: Set Active Storage Area (P80)
1: 3 Input Storage
2: 2 Loc [ Amp ]
10: Standard Deviation (P82)^15810
1: 1 Reps
2: 3 Sample Loc [ Sensor ]
11: End (P95)
The above CR21X program may provide an adequate waveform because the
program makes more than two measurements per period (Nyquist Frequency)
and samples many periods. However, if the datalogger’s Burst Measurement
Instruction is used with specific settings, the program will make more
measurements per cycle assuring that complete periods for both 50 and 60 Hz
(5 at 50 Hz and 6 at 60 Hz) will be monitored (see FIGURE 6-2).
17
CS11-L Current Transformer
6.5 CR1000 with Multiplexer Sample Program
6.5.1 Example CR1000 program reading 32 CS11-L Current Tranformers
'CR1000 program to measure rms current
PipeLineMode 'must be pipeline mode
Const num_samples = 100 '6 waveforms for 60 Hz, 5 waveforms for 50 Hz
Const NumSensors=32 'Number of Sensors on the Mux MUX in 2X32 Mode *****
'Sensor wired to Low on each of the 32 channels.
'Odd Low on Mux wired to SE2 on Datalogger
Public Amps(NumSensors), i, Batt_Volt 'the line current
Public Amp_mult, TempAmps
Dim i_sig (num_samples) 'to hold the burst measurements, each 100 samples long
PreserveVariables 'to store values between power cycles
DataTable (AmpTable,True,-1)
DataInterval (0,1,Min,10)
Maximum (NumSensors,Amps,IEEE4,False,False)
Average (NumSensors,Amps,FP2,False)
EndTable
BeginProg
Amp_mult = 0.2 '0.2 multiplier for the CS11-L
Scan (10,Sec,0,0)
Battery (Batt_volt)
'Turn AM16/32 Multiplexor On
PortSet(4,1)
i=0
SubScan(0,uSec,NumSensors)
'Switch to next AM16/32 Multiplexer Channel
PulsePort(5,10000)
i=i+1
VoltSe (i_sig (1), num_samples, mV2500,-2, True, 1000, 0, 1.0, 0)
StdDevSpa (Amps(i), num_samples, i_sig (1))
Amps(i) = Amps(i) * Amp_mult 'put in amps
If Amps(i) <= 0.15 Then Amps(i) = 0
NextSubScan
'Turn AM16/32 Multiplexer Off
PortSet(4,0)
CallTable (AmpTable)
NextScan
EndProg
This program uses the CR1000 and an AM16/32-series multiplexer to read 32
CS11-L Current Transformers.
18
6.6 CR10X with Multiplexer Sample Program
This program uses the CR10X and an AM16/32-series multiplexer to read 32
CS11-L current transformers.
CS11-L Current Transformer
6.6.1 Example CR10X program reading 32 CS11-L Current Transformers
;{CR10X}
; Example program for CS11-L
;
; Program to test the CS11-L sensor on a CR10X datalogger
; and AM1632 Multiplexer.
;
*Table 1 Program
01: 30 Execution Interval (seconds)
; Turn on the multiplexer
1: Do (P86)
1: 41 Set Port 1 High
2: Excitation with Delay (P22)
1: 1 Ex Channel
2: 0 Delay W/Ex (0.01 sec units)
3: 15 Delay After Ex (0.01 sec units)
4: 0 mV Excitation
3: Beginning of Loop (P87)
1: 0000 Delay
2: 32 Loop Count
; Clock multiplexer to next channel
4: Do (P86)
1: 72 Pulse Port 2
5: Excitation with Delay (P22)
1: 1 Ex Channel
2: 0 Delay W/Ex (0.01 sec units)
3: 1 Delay After Ex (0.01 sec units)
4: 0 mV Excitation
6: Do (P86)
1: 1 Call Subroutine 1
; This part of the program will calculate the rms Amperage
; Standard Deviation in this part of the code works mathematically the same
; as rms calculation, and it is easier to program this way. The rms
; value is calculated and stored back into an input location for further
; processing if needed.
7: Do (P86)
1: 2 Call Subroutine 2
8: Step Loop Index (P90)
1: 2 Step
9: Z=X (P31)
1: 2 X Loc [ BurstAmps ]
2: 4 -- Z Loc [ CS11_1 ]
19
CS11-L Current Transformer
10: Do (P86)
1: 3 Call Subroutine 3
11: Z=X (P31)
1: 3 X Loc [ Burst_A2 ]
2: 5 -- Z Loc [ CS11_2 ]
12: End (P95)
13: Do (P86)
1: 51 Set Port 1 Low
; This part of the program will store a one minute average of the amperage.
14: If time is (P92)
1: 0 Minutes (Seconds --) into a
2: 1 Interval (same units as above)
3: 10 Set Output Flag High (Flag 0)
15: Set Active Storage Area (P80)^17815
1: 1 Final Storage Area 1
2: 60 Array ID
16: Real Time (P77)^10331
1: 1220 Year,Day,Hour/Minute (midnight = 2400)
17: Average (P71)^5143
1: 64 Reps
2: 4 Loc [ CS11_1 ]
*Table 2 Program
02: 0.0000 Execution Interval (seconds)
*Table 3 Subroutines
;
; Parameter 2 should be 2500 mV for 50-200 amps
; should be 250 mV for 5-49 amps
; should be 25 mV for 0-4.9 amps
; Parameter 5 should be 2.0 msec for 50 Hz or 60 Hz
; Parameter 6 should be 0.05 thousand scans for 50 Hz or 60 Hz
; if parameter 5 & 6 are 2.0 and 0.05, then you have 5 complete cycles at 50 Hz
; or 6 complete cycles at 60 Hz.
1: Beginning of Subroutine (P85)
1: 1 Subroutine 1
2: Burst Measurement (P23)
1: 1 Input Channels per Scan
2: 15 2500 mV Fast Range
3: 1 In Chan
4: 0001 Trig/Trig/Dest/Meas Options
5: 2.0 Time per Scan (msec)
6: .05 Scans (in thousands)
7: 0 Samples before Trigger
8: 0.0 mV Limit
9: 0000 mV Excitation
20
10: 71 Loc [ Amps_1 ]
11: .2 Multiplier
12: 0.0 Offset
3: Burst Measurement (P23)
1: 1 Input Channels per Scan
2: 15 2500 mV Fast Range
3: 2 In Chan
4: 0001 Trig/Trig/Dest/Meas Options
5: 2.0 Time per Scan (msec)
6: .05 Scans (in thousands)
7: 0 Samples before Trigger
8: 0.0 mV Limit
9: 0000 mV Excitation
10: 123 Loc [ AmpsII_1 ]
11: .2 Multiplier
12: 0.0 Offset
4: End (P95)
5: Beginning of Subroutine (P85)
1: 2 Subroutine 2
6: Z=F x 10^n (P30)
1: 0.0 F
2: 00 n, Exponent of 10
3: 1 Z Loc [ Counter ]
7: Beginning of Loop (P87)
1: 0 Delay
2: 50 Loop Count
8: Z=Z+1 (P32)
1: 1 Z Loc [ Counter ]
9: If (X<=>F) (P89)
1: 1 X Loc [ Counter ]
2: 1 =
3: 50 F
4: 10 Set Output Flag High (Flag 0)
10: Set Active Storage Area (P80)
1: 3 Input Storage Area
2: 2 Loc [ BurstAmps ]
11: Standard Deviation (P82)^13110
1: 1 Reps
2: 71 -- Sample Loc [ Amps_1 ]
12: End (P95)
13: End (P95)
14: Beginning of Subroutine (P85)
1: 3 Subroutine 3
CS11-L Current Transformer
21
CS11-L Current Transformer
15: Z=F x 10^n (P30)
1: 0.0 F
2: 00 n, Exponent of 10
3: 1 Z Loc [ Counter ]
16: Beginning of Loop (P87)
1: 0 Delay
2: 50 Loop Count
17: Z=Z+1 (P32)
1: 1 Z Loc [ Counter ]
18: If (X<=>F) (P89)
1: 1 X Loc [ Counter ]
2: 1 =
3: 50 F
4: 10 Set Output Flag High (Flag 0)
19: Set Active Storage Area (P80)
1: 3 Input Storage Area
2: 3 Loc [ Burst_A2 ]
20: Standard Deviation (P82)^6732
1: 1 Reps
2: 123 -- Sample Loc [ AmpsII_1 ]
21: End (P95)
22: End (P95)
End Program
22
Appendix A. Theory of Operation
A.1 Typical Electrical Circuit
An example of a typical electrical circuit is a generator that provides energy in
the form of a 60 Hz sine wave. The energy is carried from the point of
generation to the point of consumption via two wires. The generator creates an
electrical load that lights up the light bulb (see FIGURE A-1).
FIGURE A-1. Generator schematic
To determine the consumption (amps) of the load, a way is needed to measure
what is passing through the wires.
A sensor is added to the circuit to measure the amperage going through the
circuit (see FIGURE A-2 through FIGURE A-4). This sensor is called a CT or
Current Transformer. The CS11-L is a current transformer.
CR1000
Datalogger
mV burst
Then
Calculate RMS
FIGURE A-2. Schematic of generator with current transformer
A-1
Appendix A. Theory of Operation
Wire added during
installation
Internal shape of
the transformer
CS11-L
FIGURE A-3. Schematic of current transformer with the wire
FIGURE A-4. CS11-L with the wire
A.2 Current Transformer Description
A current transformer is a special kind of transformer that transfers energy
from one side to another through magnetic fluxes (see FIGURE A-5).
FIGURE A-5. Magnetic flux schematic
A-2
Appendix A. Theory of Operation
The formula for a transformer is as follows (Equation A):
i
• n1 = i2 • n2 Equation A
1
Where i = amps and n = number of turns or windings
And where n
is the primary winding and n2 is the secondary
1
With the current transformer, the primary coils or windings are minimized to
avoid removing power out of the circuit, but still have a signal large enough to
measure (see FIGURE A-6).
Only 1 pass
Many windings
FIGURE A-6. Windings schematic
A small amount of current is transferred to the secondary coil.
Find the current induced on the secondary windings by solving for i
:
2
i
= i1 • n1/n2 Equation B
2
For example: The CS11-L current transducer has an n2 value of 2000
windings. If 20 amps pass through the primary winding, the following
amperage is produced on the secondary winding:
= 20 • (1/2000) = 0.01 amp on secondary winding
i
2
A.3 Converting a Milliamp Signal to a Millivolt Signal
After the current is transformed from one level to another level, the amperage
signal must be converted to a voltage signal so that the datalogger can measure
it.
Use Ohm’s Law (Equation C) to convert amperage to voltage:
E = I • R (E=Volts, I = Amps, R = Ohms) Equation C
For example: Using the previous example:
E = 0.01 amps • R
A-3
Appendix A. Theory of Operation
The CS11-L contains a 10-ohm burden (shunt) resistor (R=10 ohm).
Therefore, E is:
E = 0.01 amps • 10 ohms = 0.1 volts (or 100 mV)
From these calculations, it can be determined if a better resolution on the
measurement is needed. The Range Code can be lowered to 250 mV for some
dataloggers.
A.4 Multiplier
Use Equation D to calculate the multiplier.
m=C•n
Where, C = a correction constant
If a correction constant of 1 is assumed, then the equation can be solved from
the above information.
m = 1 • 2000/1 • (1/10) • (1/1000) = 0.2 multiplier
A.5 CS11-L Details
The CS11-L consists of a CR Magnectic’s CR8459 Current Transducer with a
10-ohm burden resistor incorporated into its cable (see FIGURE A-7). The
resistor allows most of our dataloggers to measure it.
CS11-L
•(1/R)•(1 V/1000 mV) Equation D
2/n1
Cable
WHITE
RED
BLACK
CLEAR
A-4
All Other
Dataloggers
SE
1250 mV offset
Wire Color
WHITE
RED
BLACK
CLEAR
CR200X
Datalogger
SE
VX (EX)
FIGURE A-7. CS11-L schematic
CR200X-series dataloggers require special treatment because they cannot
measure negative values; range is only 0 to 2500 mV (see FIGURE A-8). To
create positive reference, the CS11-L uses Voltage Excitation to shift the
measurement range (see FIGURE A-8 and FIGURE A-9).
1250 mV Offset (needed for CR200X)
80
60
40
20
0
mV
-20
-40
-60
-80
12 3456 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
Samples
FIGURE A-8. Adding 1250 mV creates positive output
2500
Appendix A. Theory of Operation
1400
1350
1300
1250
mV
1200
1150
1100
12 3456 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
Samples
0 mV Offset for Dataloggers other than CR200X
Adjusted Measurement Range
mV signal CR200X
2000
1500
1000
mV
500
0
FIGURE A-9. CS11-L measurement range
A.6 Multiple Passes Through the Sensor
Multiple passes can pass through the sensor to amplify the signal of the
amperage being measured (FIGURE A-10). However, the multiplier will need
to be changed, depending on how many passes through the sensor.
NOTE
The range code needs to be changed to match the number of wire
passes through the sensor.
Passes New Multiplier Range Code
2 0.1 x2
4 0.05 x4
5 0.04 x5
8 0.025 x8
10 0.02 x10
20 0.01 x20
A-5
Appendix A. Theory of Operation
FIGURE A-10. CS11-L with a wire making two passes through the
sensor
A-6
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