Caen ELS FLUCS CT-200 User manual

<
DC Current Transducers
CT-200
CT-300
CT-400
User’s Manual
All Rights Reserved
© CAEN ELS s.r.l.
Rev. 1.5 –November 2022
PRECISION CURRENT TRANSDUCERS

CT-200/CT-300/CT-400 User’s Manual
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CAEN ELS s.r.l.
Via Vetraia, 11
55049 Viareggio (LU) –Italy
Mail: [email protected]
Web: www.caenels.com

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Table Of Contents
1. INTRODUCTION................................................................................................9
1.1 <CURRENT TRANSDUCERS OVERVIEW .....................................................9
1.2 CT-200/CT-300/CT-400 MODELS AND VERSIONS.......................................10
2. INSTALLATION AND OPERATION............................................................12
2.1 MECHANICAL CONSIDERATIONS...................................................................12
2.2 CONNECTOR PINOUT.....................................................................................13
2.3 SECONDARY-SIDE SIGNALS...........................................................................14
2.3.1 Power Supply ...........................................................................................14
2.3.2 Secondary Current (current versions only) .............................................14
2.3.3 Voltage Output (“V” versions only) ........................................................14
2.3.4 STATUS Signal.........................................................................................15
2.4 MOUNTING....................................................................................................17
2.5 PRIMARY CURRENT PATH.............................................................................18
2.6 FULL-SCALE CURRENT .................................................................................19
3. ORDERING OPTIONS.....................................................................................20
4. TECHNICAL SPECIFICATIONS ..................................................................21
4.1 EQUIVALENT INPUT NOISE............................................................................22
4.2 INSULATION CHARACTERISTICS ....................................................................24
4.3 EXTERNAL SHUNT RESISTOR ........................................................................25
5. MECHANICAL DIMENSIONS.......................................................................27

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Document Revisions
Revision
Date
Comment
1.0
September 16th 2014
Document created
1.1
September 23th 2014
Added power supply recommendation section
1.2
November 3rd 2014
Manual graphics changed
1.3
July 8th 2016
Added data to technical specifications
1.4
March 12th 2018
Added information on GND connection
1.5
November 23rd 2022
Added UKCA compliance logo. Fixed spaces
in Flucs logo along the whole document.

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PS1215 –Power Supply Recommendations
We strongly recommend using this product with the CAEN ELS PS1215 power
supply, which has been especially deigned in order to obtain low-noise operation and it
is suited for DCCT measurement system where switching power supplies could corrupt
measuring accuracy, precision and noise.
The power supply is available in two different versions, one to be used with the
current-output DCCTs and one with the voltage-output ones (the PS1215V is shown in
the previous image):
Product Code
Description
WPS1215VXAAA
PS1215V - AC/DC Single Output - Dual Voltage ±15V Low
Noise Power Supply - 27W max - 3m cable with DB-9 and
BNC (Voltage Output)
WPS1215IXAAA
PS1215I - AC/DC Single Output - Dual Voltage ±15V Low
Noise Power Supply - 27W max - 3m cable with DB-9 and
banana plugs (Current Output)
For more information or further details please refer to the PS1215 User’s
Manual.
AC Line Input
“Power Good”
LED monitors
DCCT side
SUB-D connector
BNC connection for
Voltage-Output DCCT

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Safety information - Warnings
CAEN ELS will repair or replace any product within the guarantee period if the
Guarantor declares that the product is defective due to workmanship or materials and
has not been caused by mishandling, negligence on behalf of the User, accident or any
abnormal conditions or operations.
Please read carefully the manual before operating any part of the instrument
WARNING
Do NOT open the boxes
CAEN ELS d.o.o. declines all responsibility for damages or injuries caused
by an improper use of the Modules due to negligence on behalf of the User. It is
strongly recommended to read thoroughly this User's Manual before any kind of
operation.
CAEN ELS d.o.o. reserves the right to change partially or entirely the contents of this
Manual at any time and without giving any notice.
Disposal of the Product
The product must never be dumped in the Municipal Waste. Please check your local
regulations for disposal of electronics products.

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Read over the instruction manual carefully before using the instrument.
The following precautions should be strictly observed before using the device:
WARNING
•Do not use this product in any manner not
specified by the manufacturer. The protective
features of this product may be impaired if it is
used in a manner not specified in this manual.
•Do not use the device if it is damaged. Before you
use the device, inspect the instrument for possible
cracks or breaks before each use.
•Do not operate the device around explosives gas,
vapor or dust.
•Always use the device with the cables provided.
•Turn off the device before establishing any
connection.
•Do not operate the device with the cover removed
or loosened.
•Do not install substitute parts or perform any
unauthorized modification to the product.
•Return the product to the manufacturer for service
and repair to ensure that safety features are
maintained
CAUTION
•This instrument is designed for indoor use and in
area with low condensation.

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The following table shows the general environmental requirements for a correct
operation of the instrument:
Environmental Conditions
Requirements
Operating Temperature
0°C to 50°C
Operating Humidity
30% to 85% RH (non-condensing)
Storage Temperature
-10°C to 60°C
Storage Humidity
5% to 90% RH (non-condensing)

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1.Introduction
This chapter describes the general characteristics and main features of the <
current transducers.
1.1 <Current Transducers Overview
The < current transducers family is based on a closed loop technology that
allows accurate and precise monitoring of DC and AC currents with high bandwidth.
Main characteristics of the entire <family are negligible temperature
coefficient, excellent linearity and extremely low noise.
The transducers CT-Series family has a transform ratio between primary and
secondary. The transform ratio value depends over the CT-Series model. External
plastic casing guarantees galvanic isolation between the primary and the secondary
circuits in order to allow to current measurements at a different potential and simplifies
interfacing when using the <, as the feedback element of current regulated power
supplies. The internal conductive casing guarantees higher noise immunity and reduces
undesired noise pick-up from external sources.
DC current transformers and transducers represent the ideal replacement for
systems where Hall-effect sensors or shunt resistors are used as current sensing
elements and better performances are needed.
Main application fields for these current transducers are precise and extremely
stable regulated power supplies and power inverters.
Due to the excellent characteristics, the <transformers can be used in a
variety of calibration, acceptance testing and quality control applications in the
industrial and automotive fields.

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1.2 CT-200/CT-300/CT-400 Models and Versions
The CT-200, CT-300 and CT-400 current transducers are available in two
different versions that differ by the output type:
•standard secondary current output or
•buffered voltage output, where low temperature coefficient shunt resistor and low-
noise amplifier are embedded in the internal electronics in the “V” model.
Connections for power supply and output signals are available through a
standard D-SUB connector (also known as “DE-9”).
The different models and versions of the CT-200, CT-300 and CT-400 are
summarized in the following table (Table 1):
Product Code
Model
Description
WCT200XAAAAA
CT-200
200 A Primary Current <, Current-Output
WCT200VXAAAA
CT-200V
200 A Primary Current <, Voltage-Output
WCT300XAAAAA
CT-300
300 A Primary Current <, Current-Output
WCT300VXAAAA
CT-300V
300 A Primary Current <, Voltage-Output
WCT400XAAAAA
CT-400
400 A Primary Current <, Current-Output
WCT400VXAAAA
CT-400V
400 A Primary Current <, Voltage-Output
Table 1: CT-200, CT-300 and CT-400 versions and models
The CT-Series transducer with the current output acts mainly as a transformer
(with DC capability) that converts a full-scale bipolar primary current to a secondary
current up to ±400 mA. The CT-200, CT-300 and CT-400 have a maximum secondary
output current of ±200 mA.
The voltage-output “V” version converts the primary bipolar full-scale current
to a secondary output voltage of ±10 V.

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Front view of a CT-200/CT-300/CT-400 current transducer is presented in
Figure 1.
Figure 1: front view of a CT-200, CT-300 or CT-400 <current transducer
Rear view of the same current transducer, where self-threading holes for screws
are visible, is presented in Figure 2.
Figure 2: rear view of a CT-200, CT-300 or CT-400 <current transducer

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2.Installation and Operation
General considerations and description of pinout and functionalities are herein
presented.
2.1 Mechanical Considerations
Each version of the CT-Series current transducer presents an embossed “arrow”
with the CAEN ELS logo on one side of the plastic casing that indicates the verse of
the positive primary current measurement. This arrow can be seen in Figure 3 on the
right side of the enclosure.
Figure 3: embossed arrow indicating the verse of positive primary current
Positive
Current
Negative Current
Embossed arrow
indicating the verse
of positive primary
current

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2.2 Connector Pinout
The CT-200, CT-300 and CT-400 have a standard D-SUB 9-pin (or, commonly
referred to as “DE-9”) in both their current output and voltage output versions. The
standard pin numbering to refer to is herein presented in Figure 4.
Figure 4: D-sub 9 connector pin numbering
The pinout for the two versions are presented in Table 2. These two versions
have current or voltage output pins (and their signal returns).
Pin #
CT-200, CT-300, CT-400
(Current Output)
CT-200V, CT-300V, CT-400V
(Voltage Output)
1
ISreturn
nc - GND
2
nc
VOUT
3
Status -
4
GND
5
-15V
6
IS
Internal Use
7
nc
VOUT return
8
Status +
9
+15V
Table 2: CT-200, CT-300 and CT-400 pinout
Please note that pins not internally connected on the specific model are indicated
in Table 2 as nc = not connected. Please DO NOT connect any signal to the pins
indicated as Internal Use. Please note that, internally, Is is directly connected to
GND.
Pin #9
Pin #5
Pin #1
Pin #6

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2.3 Secondary-side Signals
The signals on the “secondary” side of the CT-200, CT-300 and CT-400 current
transducers are found on pins #1, 2, 3, 6, 7 and 8 (please note that not all of them are
present on all versions) of the DE-9 connector.
2.3.1 Power Supply
Supply voltages for the CT-200, CT-300 and CT-400 have to be fed to pin #9
(+15V) and to pin #5 (-15V) of the D-sub 9-pin connector; both these voltages are
referred to pin #4 (GND).
Maximum current that can be drawn from each one of these supply voltages is
of 250 mA for all three models –i.e. CT-200, CT-300 and CT-400 (a maximum of 50
mA for supplying the internal electronics circuits and a maximum of 200 mA for the
secondary current).
2.3.2 Secondary Current (current versions only)
On the “standard”current output versions the secondary current output IS,
scaled by its current transformation ratio is fed to pin #6. Current return pins are
respectively found on pin #1 and on pin #7.
Maximum secondary current depends over the full-scale range and the current
transform ratio of the sensor. For example for a CT-200 the full-scale range is ±200 A
and its transformation ratio is 1:1000, thus its maximum secondary current is rated at
±200 mA. An external shunt resistor, which can be placed close to the user’s desired
measuring circuit (to avoid the noise pick-up), is needed in order to convert the current
signal to a voltage.
The voltage output pins (VOand VORET) cannot be found on standard current
output versions.
2.3.3 Voltage Output (“V” versions only)
A buffered output voltage signal is present on the voltage output versions of the
transducers in order to allow easier connection of the DCCT to an external circuit or an
Analog to Digital converter (ADC).
The full-scale output bipolar signal VO(pin #2 for “V”-version) is referred to
VORET(pin #7) and the behavior is as follows:
•+10V output if the primary current is equal to positive full scale of the sensor;
•–10V output if the primary current is equal to negative full scale of the sensor.

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This behavior can be resumed in the gain parameter G, in [V/A], expressed as
the ratio between the transducer output voltage 󰇛 󰇜and the primary current
IP.
   

VORET pin is not internally connected to ground GND (pin #4) and it should
be connected to ground directly using a single-point connection (e.g. on an external
ADC ground pins or VIN- pin). The availability of this “return” signal is very useful in
order to avoid additional ground-loops and noise pickup on the voltage-output version
of the transducer.
Please note that the maximum differential voltage between the VORET and the
GND pin has to be kept within ±0.5V.
    
In the voltage output “V”-version of the transducers the current output pin IS
(pin #6) and its return (pin #1) are not present.
Please note that output impedance for the “V”-version models is 50 Ω and it is
low-pass filtered with a 0.5-µs time constant.
2.3.4 STATUS Signal
A STATUS signal, obtained from the outputs of an optocoupler phototransistor
(Status+ and Status–, pins #8 and #3) is present on all versions. Please note that the
OK- signal is not internally connected to the ground potential and can be connected to
an external reference potential. A green LED is also present on the front side of the
DCCT indicating the correct operation of the devices.
A pull-up resistor is needed (between the OK+ and some supply voltage referred
to the OK- potential) in order to correctly obtained the correct signaling.
Two examples on how to connect the OK+ and OK- signals are hereafter
presented in Figure 5 and in Figure 6.
Figure 5: OUT OK signals connections using the +15V and the GND pins

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Figure 6: OUT OK signals connections as digital interfacing to +3.3V
Note that the connection scheme presented in Figure 5 is referred to the GND
potential and the OK_SIGNAL is at low level (<0.4V) if the current transducer is
correctly working while it is at high level (>14.5V) when the transducer is not.
In the configuration presented in Figure 6, the current transducer can be easily
interfaced to a digital microcontroller, a Digital Signal Processor or an FPGA, supplied
by a +3.3V voltage source.
Please note that the +3.3V supply and the OK_SIGNAL is referred to DGND
potential, which can be the same or different from the GND potential on which the
transducer device is supplied from. The OK_SIGNAL is found to be at low level
(<0.4V) when the transducer is correctly working and at high-level (>3V) when not.
Figure 7: STATUS –OUT OK indications
The OUT OK green light is on, as shown in Figure 7, whenever the device is
correctly working and regulating secondary output current –i.e. zero flux is established
and secondary circuit is closed on the shunt resistor (external or internal in the “V”
versions).

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2.4 Mounting
The current transducers can be mounted in different configurations, depending
on user’s needs and opportunities, but heatsink shall never be faced to the floor.
The transducers are designed to be used in rack-mount applications, by means of
any of the two (2) different 4-hole patterns placed in different sides of the mechanical
case.
Four holes are present on the bottom of the device as indicated in the Figure 8.
Figure 8: bottom mounting holes pattern
Other four holes are present on the rear side of the plastic cover and can be used
in order to fix the device by means of self-threading screws. These holes are indicated
in Figure 9.
Figure 9: rear mounting holes for self-threading screws
Mounting
Holes
Mounting
Holes
Fixing
Holes

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The self-threading screws can have a maximum length of 15 mm (2.9 mm
diameter) and the types that can be used are hereafter listed:
•UNI 8119
•DIN 7504 - P
•ISO 15482
2.5 Primary Current Path
A non-symmetrical layout of the primary current return path may degrade the
accuracy and the noise of the current transducer. A cross section of the transducer
plastic case illustrates what happens if the primary current is not equally distributed
over the perimeter of the current transducer head.
Figure 10: primary current path; non-recommended layout (left)
and recommended layout (right)
Figure 10 (left) shows what happens if the primary current is routed over one
side of the DCCT head: the Magnetic flux density is higher in the area between the “U”
path.
If the current path return is split in two or more paths over the DCCT Head, the
magnetic flux density is more homogenous over the perimeter and the resulting
measurement will be more accurate. If the split return path is not possible, it is
preferable to keep the retuning cable as far as possible from the DCCT Head.
DCCT Head
Primary Current

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2.6 Full-Scale Current
Rated full-scale primary current can be easily changed by carrying out multiple
turns on the primary conductor hole.
The full-scale current can then be scaled by a factor of N, with N= number of
turns of the primary conductor around the hole. As an example (see figure Figure 11),
a primary full-scale current of 300 A (in the CT-300 model) can be easily scaled by a
factor 2 (applying two primary turns), and so the obtained full-scale will be 150 A or
by a factor 3 (applying three turns) and so the obtained full-scale will be 100 A and so
on.
Figure 11: primary full-scale current scaled by a factor 2 (2 primary turns - left) and
scaled by 3 (3 primary turns - right)
Do not apply rated nominal full-scale primary current (for example 400A
for CT-400) when carrying out multiple turns on primary conductor hole.

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3.Ordering Options
The CT-200, CT-300 and CT-400 current transducers have two different
versions differing by the secondary output signal types. The ordering code is formatted
as follows:
C
T
-
M
M
M
X
NOTE: fields/characters shaded in grey color are fixed.
Output Version
empty = current output
V = voltage output
Full-Scale
200 = ±200A Full-Scale
300 = ±300A Full-Scale
400 = ±400A Full-Scale