Beckhoff KS31 2 Series User manual

Documentation | EN
KL31x2/KS31x2
Two Channel Accurate Analog Terminals
2023-01-31 | Version: 2.6.0

Table of contents
KL31x2/KS31x2 3Version: 2.6.0
Table of contents
1 Foreword....................................................................................................................................................5
1.1 Notes on the documentation .............................................................................................................5
1.2 Safety instructions.............................................................................................................................6
1.3 Documentation issue status ..............................................................................................................7
2 Product overview ......................................................................................................................................9
2.1 KL3132, KL3162, KL3172, KL3182...................................................................................................9
2.1.1 Introduction ........................................................................................................................9
2.1.2 Technical data..................................................................................................................10
2.2 KL3142, KL3152 ............................................................................................................................11
2.2.1 Introduction ......................................................................................................................11
2.2.2 Technical data..................................................................................................................12
2.3 LEDs ...............................................................................................................................................13
2.4 Basic function principles..................................................................................................................14
2.5 Continuative documentation for I/O components with analog in and outputs .................................17
3 Mounting and wiring ...............................................................................................................................18
3.1 Instructions for ESD protection .......................................................................................................18
3.2 Installation on mounting rails...........................................................................................................19
3.3 Disposal ..........................................................................................................................................21
3.4 Connection ......................................................................................................................................22
3.4.1 Connection system........................................................................................................... 22
3.4.2 Wiring ...............................................................................................................................24
3.4.3 Shielding ..........................................................................................................................25
3.4.4 Contact assignment ......................................................................................................... 26
3.5 ATEX - Special conditions (standard temperature range)...............................................................28
3.6 Continuative documentation for ATEX and IECEx..........................................................................29
3.7 Application example for KL3172-0000 ............................................................................................30
4 Configuration Software KS2000 ............................................................................................................31
4.1 KS2000 - Introduction .....................................................................................................................31
4.2 Parameterization with KS2000........................................................................................................33
4.3 Register...........................................................................................................................................35
4.4 Settings ...........................................................................................................................................36
4.5 Sample program for register communication via EtherCAT on KL3314 exemplary........................38
5 Data structures........................................................................................................................................41
5.1 Process image ................................................................................................................................41
5.2 Mapping ..........................................................................................................................................42
5.3 Control and status byte ...................................................................................................................44
5.4 Register overview............................................................................................................................47
5.5 Register description ........................................................................................................................48
5.6 Examples of Register Communication ............................................................................................54
5.6.1 Example 1: Reading the firmware version from register 9 ............................................... 54
5.6.2 Example 2: Writing to an user register ............................................................................. 54
6 Appendix..................................................................................................................................................58
6.1 Beckhoff Identification Code (BIC) ..................................................................................................58

Table of contents
KL31x2/KS31x24 Version: 2.6.0
6.2 Support and Service........................................................................................................................60

Foreword
KL31x2/KS31x2 5Version: 2.6.0
1 Foreword
1.1 Notes on the documentation
Intended audience
This description is only intended for the use of trained specialists in control and automation engineering who
are familiar with the applicable national standards.
It is essential that the documentation and the following notes and explanations are followed when installing
and commissioning these components.
It is the duty of the technical personnel to use the documentation published at the respective time of each
installation and commissioning.
The responsible staff must ensure that the application or use of the products described satisfy all the
requirements for safety, including all the relevant laws, regulations, guidelines and standards.
Disclaimer
The documentation has been prepared with care. The products described are, however, constantly under
development.
We reserve the right to revise and change the documentation at any time and without prior announcement.
No claims for the modification of products that have already been supplied may be made on the basis of the
data, diagrams and descriptions in this documentation.
Trademarks
Beckhoff®, TwinCAT®, TwinCAT/BSD®, TC/BSD®, EtherCAT®, EtherCATG®, EtherCATG10®, EtherCATP®,
SafetyoverEtherCAT®, TwinSAFE®, XFC®, XTS® and XPlanar® are registered trademarks of and licensed by
Beckhoff Automation GmbH. Other designations used in this publication may be trademarks whose use by
third parties for their own purposes could violate the rights of the owners.
Patent Pending
The EtherCAT Technology is covered, including but not limited to the following patent applications and
patents: EP1590927, EP1789857, EP1456722, EP2137893, DE102015105702 with corresponding
applications or registrations in various other countries.
EtherCAT® is registered trademark and patented technology, licensed by Beckhoff Automation GmbH,
Germany.
Copyright
© Beckhoff Automation GmbH & Co. KG, Germany.
The reproduction, distribution and utilization of this document as well as the communication of its contents to
others without express authorization are prohibited.
Offenders will be held liable for the payment of damages. All rights reserved in the event of the grant of a
patent, utility model or design.

Foreword
KL31x2/KS31x26 Version: 2.6.0
1.2 Safety instructions
Safety regulations
Please note the following safety instructions and explanations!
Product-specific safety instructions can be found on following pages or in the areas mounting, wiring,
commissioning etc.
Exclusion of liability
All the components are supplied in particular hardware and software configurations appropriate for the
application. Modifications to hardware or software configurations other than those described in the
documentation are not permitted, and nullify the liability of Beckhoff Automation GmbH & Co. KG.
Personnel qualification
This description is only intended for trained specialists in control, automation and drive engineering who are
familiar with the applicable national standards.
Description of instructions
In this documentation the following instructions are used.
These instructions must be read carefully and followed without fail!
DANGER
Serious risk of injury!
Failure to follow this safety instruction directly endangers the life and health of persons.
WARNING
Risk of injury!
Failure to follow this safety instruction endangers the life and health of persons.
CAUTION
Personal injuries!
Failure to follow this safety instruction can lead to injuries to persons.
NOTE
Damage to environment/equipment or data loss
Failure to follow this instruction can lead to environmental damage, equipment damage or data loss.
Tip or pointer
This symbol indicates information that contributes to better understanding.

Foreword
KL31x2/KS31x2 7Version: 2.6.0
1.3 Documentation issue status
Version Comment
2.6.0 • Chapter Basic function principles updated
• Reference to the further documentation I/O Analog Manual added
• Revision status updated
2.5.0 • Chapter Technical data updated
• Document structure updated
• Chapter Instructions for ESD protection added
• Chapter Disposal added
• New title page
2.4.0 • Note on differential measurement added
2.3.0 • Example program added to chapter KS2000 Configuration software
2.2.0 • Chapter Technical data updated (voltage measurement terminals only)
2.1.0 • Chapter Basic function principles updated
2.0.0 • Migration
1.6.0 • Title page and introduction corrected
• Preface updated
• Technical data updated
1.5.0 • Register description updated (R32)
• Technical data updated
• KL3172-0500 and KL3172-1000 added
• ATEX notes added
1.4 • Control and status byte updated
• Mounting description expanded
1.3 • LED descriptions updated (prisms, new RUN LEDs)
• Connection description updated (power contacts, new pin assignment for terminal points)
• Channel switch-off added
• Technical data of the KL3142 and KL3152 updated
1.2.1 • Pin assignment corrected
1.2 • Register description extended (command 7000)
1.1 • Technical data updated
• Description of terminal points 3 and 7 adapted to final pin assignment
• KL3132, KL3142, KL3152, KL3162 and KL3182 added
1.0 First version (KL3172 only)

Foreword
KL31x2/KS31x28 Version: 2.6.0
Firmware and hardware versions
Documen-
tation,
Version
KL3132,
KS3132
KL3142,
KS3142
KL3152,
KS3152
KL3162,
KS3162
KL3172,
KS3172
KL3172-0500,
KS3172-0500,
KL3172-1000,
KS3172-1000
KL3182,
KS3182
Firmw Hardw Firmw Hardw Firmw Hardw Firmw Hardw Firmw Hardw Firmw Hardw Firmw Hardw
2.6.0 2D 05 3A 06 3A 07 2E 06 2D 04 2D 04 2D 05
2.5.0 2D 05 3A 06 3A 07 2D 06 2D 04 2D 04 2D 05
2.4.0 2D 05 2E 05 2D 05 2D 06 2D 04 2D 04 2D 04
2.3.0 2D 05 2E 05 2D 05 2D 05 2D 04 2D 04 2D 04
2.2.0 2D 04 2E 04 2D 04 2D 04 2D 03 2D 03 2D 03
2.1.0 2D 04 2E 04 2D 04 2D 04 2D 03 2D 03 2D 03
2.0.0 2D 04 2E 04 2D 04 2D 04 2D 03 2D 03 2D 03
1.6.0 2D 03 2E 03 2D 03 2D 03 2D 02 2D 02 2D 02
1.5.0 2D 03 2E 03 2D 03 2D 03 2D 02 2D 02 2D 02
1.4 2A 01 2B 01 2A 01 2A 01 2A 01 - - 2A 01
1.3 2A 01 2A 01 2A 01 2A 01 2A 01 2A 01
1.2.1 1A 00 1A 00 1A 00 1A 00 1B 00 1A 00
1.2 1A 00 1A 00 1A 00 1A 00 1B 00 1A 00
1.1 1A 00 1A 00 1A 00 1A 00 1B 00 1A 00
1.0 --------B100 --
The firmware and hardware versions (delivery state) can be taken from the serial number printed on the side
of the terminal.
Syntax of the serial number
Structure of the serial number: WWYYFFHH
WW - week of production (calendar week)
YY - year of production
FF - firmware version
HH - hardware version
Example with serial number 35041B01:
35 - week of production 35
04 - year of production 2004
1B - firmware version 1B
01 - hardware version 1

Product overview
KL31x2/KS31x2 9Version: 2.6.0
2 Product overview
2.1 KL3132, KL3162, KL3172, KL3182
2.1.1 Introduction
Fig.1: KL3132
Two-channel analog terminals with voltage inputs (0.05% accuracy)
The analog input terminals KL3132, KL3162, KL3172 and KL3182 process signals in the range -10V to
+10V. The voltage is digitized to a resolution of 16bits, and is transmitted, electrically isolated, to the higher-
level automation device. The input channels of one Bus Terminal have differential inputs and possess a
common, internal ground potential. With their small measuring error of ±0.05% of the full scale value, these
terminals are optimized for high-precision control processes, suchas dosing, filling, or quality assurance.
The Bus Terminals combine 2 channels in a single housing. Status and error LEDs indicate the terminal
state.
Overview
KL3132-0000: -10... +10V
KL3162-0000:0... +10V
KL3172-0000:0.0... +2.0V
KL3172-0500:0.0... +0.5V
KL3172-1000:0.0... +1.0V
KL3182-0000: -2.0... +2.0V

Product overview
KL31x2/KS31x210 Version: 2.6.0
2.1.2 Technical data
Technical data KL3132-0000,
KS3132-0000
KL3162-0000,
KS3162-0000
KL3172-0000,
KS3172-0000
KL3172-0500,
KS3172-0500
KL3172-1000,
KS3172-1000
KL3182-0000,
KS3182-0000
Number of inputs 2
Input signal -10V ... +10V 0 ... 10V 0 ... 2V 0 ... 500mV 0 ... 1V -2V ... +2V
Input resistance >70kΩ
Common-mode voltage UCM ±10V
Resolution 16bit
Conversion time 140ms, configurable
Measuring error (full measur-
ing range)
±0.05% of the full scale value, self-calibration
Bit width in the K-Bus I/O 2 x 16bit user data (optionally 2 x 8bit control/status)
Bit width in the input process
image
2 data words, 2 status byte
Bit width in the output process
image
2 data words, 2 control byte
Power supply for the electron-
ics
via the K-bus
Current consumption from K-
bus
typically 85mA
Electrical isolation 500V (differential input / K-bus)
Connection spring-loaded system
Pluggable wiring for all KSxxxx terminals
Weight approx. 70g
Dimensions (W x H x D) approx. 15mmx100mmx70mm (width aligned: 12mm)
Mounting [}19] on 35mm mounting rail conforms to EN60715
Permissible ambient tempera-
ture range during operation
0°C ... + 55°C
Permissible ambient tempera-
ture range during storage
-25°C ... + 85°C
Permissible relative air hu-
midity
95%, no condensation
Vibration/ shock resistance conforms to EN60068-2-6/ EN60068-2-27
EMC immunity/ emission conforms to EN61000-6-2/ EN61000-6-4
Protection class IP20
Installation position variable
Approval/Markings* CE, UKCA, cULus, EAC, ATEX [}28]
*) Real applicable approvals/markings see type plate on the side (product marking).
Ex marking
Standard Marking
ATEX II 3 G Ex nA IIC T4 Gc

Product overview
KL31x2/KS31x2 11Version: 2.6.0
2.2 KL3142, KL3152
2.2.1 Introduction
Fig.2: KL3142
Two-channel analog terminals with current inputs (0.05% accuracy)
The KL3142 and KL3152 analog input terminals handle signals in the range between 0 and 20mA, and
between 4 and 20mA respectively. The current is digitized to a resolution of 16bits (default: 15bits), and is
transmitted, in an electrically isolated form, to the higher-level automation device. The input channels of the
Bus Terminals have differential inputs and possess a common, internal ground potential. With their small
measuring error of ±0.05% of the full scale value, these terminals are optimized for high-precision control
processes, such as dosing, filling, or quality assurance. The Bus Terminals combine 2 channels in a single
housing. An open lead or overload condition are detected, and the terminal status is relayed to the controller
via the K-bus. Status and error LEDs indicate the terminal state.
Overview
KL3142-0000: 0... 20mA
KL3152-0000: 4 ... 20mA

Product overview
KL31x2/KS31x212 Version: 2.6.0
2.2.2 Technical data
Technical data KL3142-0000, KS3142-0000 KL3152-0000, KS3152-0000
Number of inputs 2
Signal current 0... 20mA 4... 20mA
Internal resistance 100Ω measuring resistance
Common-mode voltage UCM ±10V
Resolution 16bit
Conversion time 140ms, configurable
Measuring error (full measuring range) ±0.05% of the full scale value, self-calibration
Bit width in the K-Bus I/O 2 x 16bit user data (optionally 2 x 8bit control/status)
Bit width in the input process image 2 data words, 2status byte
Bit width in the output process image 2 data words, 2control byte
Power supply for the electronics via the K-bus
Current consumption from K-bus typically 85mA
Surge voltage resistance 35VDC
Electrical isolation 500V (differential input / K-bus)
Connection spring-loaded system
Pluggable wiring for all KSxxxx terminals
Weight approx. 70g
Dimensions (W x H x D) approx. 15mmx100mmx70mm (width aligned: 12mm)
Mounting [}19] on 35mm mounting rail conforms to EN60715
Permissible ambient temperature range
during operation
0°C ... + 55°C
Permissible ambient temperature range
during storage
-25°C ... + 85°C
Permissible relative air humidity 95%, no condensation
Vibration/ shock resistance conforms to EN60068-2-6/ EN60068-2-27
EMC immunity/ emission conforms to EN61000-6-2/ EN61000-6-4
Protection class IP20
Installation position variable
Approval/Markings* CE, UKCA, cULus, EAC, ATEX [}28]
*) Real applicable approvals/markings see type plate on the side (product marking).
Ex marking
Standard Marking
ATEX II 3 G Ex nA IIC T4 Gc

Product overview
KL31x2/KS31x2 13Version: 2.6.0
2.3 LEDs
Fig.3: LEDs
LED Display
K-bus power
(green)
ON Power supply (5V) available on the K-bus
OFF No power supply (5V) available on the K-bus
K-Bus Run
(green)
ON Data transmission on the K-bus is active
OFF Data transmission on the K-bus is not active
Run 1
(green)
ON Channel1 active:
• process data contain valid analog value
OFF Channel1 not active:
• Calibration is performed, analog value in the process data not current (frozen or zero)
• or channel1 is switched off (if LED error1 not lit)
Error 1
(red)
ON • Analog value of channel1 is above the valid measuring range, specified through register R21 [}50] of
channel1. Bit SB1.1 [}44] is set in the status byte of channel1.
• Analog value of channel1 is below the valid measuring range, specified through register R22 [}50] of
channel1. Bit SB1.0 [}44] is set in the status byte of channel1.
• Calibration is in progress. The LED goes out when the calibration is complete.
OFF • Analog value of channel1 is within the valid measuring range (if LED Run1 is lit)
• or channel1is switched off (if LED Run1 is not lit)
Run 2
(green)
ON Channel2 active:
• process data contain valid analog value
OFF Channel2 not active:
• Calibration is performed, analog value in the process data not current (frozen or zero)
• or channel2 is switched off (if LED error2 not lit)
Error 2
(red)
ON • Analog value of channel2 is above the valid measuring range, specified through register R21 [}50] of
channel2. Bit SB2.1 [}46] is set in the status byte of channel2.
• Analog value of channel2 is below the valid measuring range, specified through register R22 [}50] of
channel2. Bit SB2.0 [}46] is set in the status byte of channel2.
• Calibration is in progress. The LED goes out when the calibration is complete.
OFF • Analog value of channel2 is within the valid measuring range (if LED Run2 is lit)
• or channel2is switched off (if LED Run2 is not lit)
Limiting the measuring range
The terminal indicates any violation of the measuring range to the higher-level controller via the status byte.
If the current measured value is:
• greater than specified in register R21 [}50], bit1 is set in the status byte,
• smaller than specified in register R22 [}50], bit0 is set in the status byte.
In both cases, the ERROR LED of the respective channel will be on. This display can be disabled through bit
R32.8 [}50].

Product overview
KL31x2/KS31x214 Version: 2.6.0
2.4 Basic function principles
The high-precision KL3172 analog input terminals can measuretwo voltages (KL3132, KL3162, KL3172,
KL3182) or two currents (KL3142, KL3152) and display them with a resolution of 16bits (65535 steps). High-
precision measurements are ensured through cyclic self-calibration.
By default, the inputs are switched as differential inputs. For terminals KL3132, KL3162, KL3172 and
KL3182, terminal point -E1 of the first channel can be switched to internal analog ground with bit R32.6
[}50] of the feature register.
Specification
The specification values are valid after at least 30 minutes warm-up time. The self-calibration largely
compensates for internal drifts, but the internal reference (like any electronic component) is slightly
temperature dependent and must stabilize.
The channels of the KL31x2 are not electrically isolated. Note CommonMode effects.
Process data
Analog values are represented as follows:
Input signal Value
KL3142-0000 KL3152-0000 KL3162-0000 KL3172-0000 KL3172-0500 KL3172-1000 dec hex
0mA 4mA 0V 0V 0V 0V 0 0x0000
20mA 20mA 10V 2V 500mV 1V 65535 0xFFFF
Input signal Value
KL3132-0000 KL3182-0000 dec hex
-10V -2V -32768 0x8000
+10V +2V +32767 0x7FFF
Calculation
The terminal continuously records measured values and stores the raw values of its A/D converter in register
R0 [}48] (RAM). After each acquisition of the analog signal, a correction is calculated using the
compensation and, if necessary, calibration values. This is followed by manufacturer and user scaling:
YA =(XADC + BA) x AA(1.0) Manufacturer compensation (if calibration inactive)
YA =((XADC + BK) x AA) x (AGK /
AK)
(1.1) Manufacturer compensation / calibration (if calibration activated)
YH =YA x AH + BH(1.2) Manufacturer scaling
Yoff =YHxAW + BW(1.3) User scaling

Product overview
KL31x2/KS31x2 15Version: 2.6.0
Legend
Name Name Unit Register
XADC Output value of the A/D converter [1] -
Yoff Process data for controller [1] -
BAVendor calibration: offset (can be deactivated via bit R32.5 [}50] of the
feature register)
[1] R17 [}49]
AAVendor calibration: gain (always active) [1 x 2-16 + 1] R18 [}49]
BKCalibration: offset (can be activated via bit R32.5 [}50] of the feature
register)
[1] R1 [}48]
AKCalibration: gain (can be activated via bit R32.5 [}50] of the feature
register)
[1] R2 [}48]
AGK Basic calibration: gain (can be activated via bit R32.5 [}50] of the
feature register)
[1] R23 [}50]
BHVendor scaling: offset (can be activated via bit R32.1 [}50] of the
feature register)
[1] R19 [}50]
AHVendor scaling: gain (can be activated via bit R32.1 [}50] of the feature
register)
[1 x 2-8 + 1] R20 [}50]
BWUser scaling: offset (can be activated via bit R32.0 [}50] of the feature
register)
[1] R33 [}52]
AWUser scaling: gain (can be activated via bit R32.0 [}50] of the feature
register)
[1 x 2-8 + 1] R34 [}52]
Calibration
The analog channels are periodically subjected to self-calibration. In this process, the field signal is
electrically separated from the internal acquisition (ADC); instead, internal reference voltages are applied
and thus essential circuit parts are acquired. Only the near-field interference suppression elements (L/C
combination) and the analog switches themselves cannot be acquired. The aim is to compensate for
temperature drift effects.
NOTE
External effect of the field separation
The described separation of the internal circuit from the signal can cause interferences on the field signal!
With normal, i.e. switched on measurement, a current flows through the KL31x2 in any case, which applies
a load to the source. This is omitted while the terminal is in self-calibration. If necessary, check the behavior
of the signal source (sensor, calibrator) with a separate measuring device in the load change moments,
whether overvoltages/undervoltages or short-term glitches/peaks occur.
The calibration interval is set in register R40 [}53] in steps of 100ms. During calibration
• no current process data are present. Value 0 is present.
• the terminal sets the SB1.6 [}44] in the status byte
• the RUN LED (green) is extinguished and Error (red) is set
Calibration can be disabled by the controller via control byte CB1.1 [}44] if necessary. If calibration is
disabled over a prolonged period, the terminal carries out a forced calibration, in order to compensate any
voltage drifts that may be caused by changes in temperature. The forced calibration interval is specified via
register R44 [}53] as a multiple of the calibration interval. If a further calibration between two cycles is
required, this can be started manually by setting bit CB1.0 [}44]. The terminal then acts as if it had triggered
a calibration itself.

Product overview
KL31x2/KS31x216 Version: 2.6.0
Fluctuating measuring signals interfere with self-calibration
In the calibration phase, the terminal uses a stabilization check to verify that the input signal is sta-
ble. Strongly fluctuating measuring signals prevent a termination of the self-calibration, it stops with
Error=1 and Overload/Underload=1, see chapter
Basics of the function/ Calibration [}15] and
Access from the user program/ Status byte1 (for process data mode) [}44].
If such a signal is expected at the system, the following can be selected
• the self-calibration via control bit CB1.1 [}44] can be blocked in the process until a steady signal
is applied and the self-calibration runs through.
• the stabilization check can be switched off with bit R32.7 [}50].
• the stabilization error display can be switched off with bit R32.14 [}50].
• the tolerance window R48 [}53] of the stabilization control can be increased.
The functionality of the calibration including all features invariably refers to both channels simultaneously!
The channels cannot be calibrated individually. For this reason, the registers R40 [}53], R44 [}53], R47
[}53] and R48 [}53] are only implemented once for both channels.
• In the first phase of the calibration, an input voltage of 0V is applied to both analog inputs (zero
calibration). The zero points of both analog input stages can be determined in this way. For this
measurement, the respective absolute value of the channels is of interest. The value is subsequently
stored in the RAM (registerR1 [}48]).
• During the second calibration phase, an internal reference voltage of approx. 1.8V (final calibration) is
applied to both analog inputs. In this case, it is no longer the absolute value of the measurement result
that is of interest, but only any deviation from the basic calibration value determined during production
(registerR23 [}50]). The ratio between the two values is calculated and used in the next correction
calculation [}14]. The value is subsequently stored in the RAM (registerR2 [}48]).
Stabilization of the calibration
During the calibration, a stabilization of the offset and gain values is carried out. The calibration values are
only accepted once a certain number (specified via register R47 [}53]) of measured values is inside a
certain tolerance range (specified via register R48 [}53]). This further increases the precision. This function
can be deactivated via bit R32.7 [}50] .
Limit values
The terminal offers the option of monitoring two limit values per channel. Limit value 1 can be specified via
register R35 [}52], and limit value 2 via register R36 [}52]. They are activated via bits in the feature
registers R32.9 [}50]and R32.10 [}50]. The status of the current process data value is indicated to the
controller via the status byte SB1 [}44]. Possible states are: Process data equal limit value (3), process
data less than limit value (2), process data greater than limit value (1).
Limiting the measuring range
The terminal indicates any violation of the measuring range to the higher-level controller via the status byte.
• If the current measured value is larger than 0xFFFF or 0x7FFF, bit SB1.1 [}44] is set.
• Is the current measured value is less than 0 or 0x8000, bit SB1.0 [}44] is set.
In both cases, the ERROR LED of the respective channel will be on. This function can be deactivated via bit
R32.8 [}50].
Differential measurement
With the KL3132, KL3162, KL3172, KL3182, the differential measurement can be deactivated with bit R32.6
[}50]. Then, for channels 1 and 2, the input is internally switched to GND at terminal point 3/7, which must
then be wired externally accordingly.

Product overview
KL31x2/KS31x2 17Version: 2.6.0
Fig.4: Differential measuring
2.5 Continuative documentation for I/O components with
analog in and outputs
NOTE
Continuative documentation Continuative documentation for I/O components
with analog in and outputs
Pay also attention to the continuative documentation
I/O Analog Manual
Notes on I/O components with analog inputs and outputs,
which is available for download on the Beckhoff homepage https://www.beckhoff.com on
the respective product pages!
It explains the basics of sensor technology and contains notes on analog measured values.

Mounting and wiring
KL31x2/KS31x218 Version: 2.6.0
3 Mounting and wiring
3.1 Instructions for ESD protection
NOTE
Destruction of the devices by electrostatic discharge possible!
The devices contain components at risk from electrostatic discharge caused by improper handling.
• Please ensure you are electrostatically discharged and avoid touching the contacts of the device directly.
• Avoid contact with highly insulating materials (synthetic fibers, plastic film etc.).
• Surroundings (working place, packaging and personnel) should by grounded probably, when handling
with the devices.
• Each assembly must be terminated at the right hand end with a KL9010 bus end terminal, to ensure the
protection class and ESD protection.
Fig.5: Spring contacts of the Beckhoff I/O components

Mounting and wiring
KL31x2/KS31x2 19Version: 2.6.0
3.2 Installation on mounting rails
WARNING
Risk of electric shock and damage of device!
Bring the bus terminal system into a safe, powered down state before starting installation, disassembly or
wiring of the bus terminals!
Assembly
Fig.6: Attaching on mounting rail
The bus coupler and bus terminals are attached to commercially available 35mm mounting rails (DIN rails
according to EN60715) by applying slight pressure:
1. First attach the fieldbus coupler to the mounting rail.
2. The bus terminals are now attached on the right-hand side of the fieldbus coupler. Join the compo-
nents with tongue and groove and push the terminals against the mounting rail, until the lock clicks
onto the mounting rail.
If the terminals are clipped onto the mounting rail first and then pushed together without tongue and
groove, the connection will not be operational! When correctly assembled, no significant gap should
be visible between the housings.
Fixing of mounting rails
The locking mechanism of the terminals and couplers extends to the profile of the mounting rail. At
the installation, the locking mechanism of the components must not come into conflict with the fixing
bolts of the mounting rail. To mount the mounting rails with a height of 7.5mm under the terminals
and couplers, you should use flat mounting connections (e.g. countersunk screws or blind rivets).

Mounting and wiring
KL31x2/KS31x220 Version: 2.6.0
Disassembly
Fig.7: Disassembling of terminal
Each terminal is secured by a lock on the mounting rail, which must be released for disassembly:
1. Pull the terminal by its orange-colored lugs approximately 1cm away from the mounting rail. In doing
so for this terminal the mounting rail lock is released automatically and you can pull the terminal out of
the bus terminal block easily without excessive force.
2. Grasp the released terminal with thumb and index finger simultaneous at the upper and lower grooved
housing surfaces and pull the terminal out of the bus terminal block.
Connections within a bus terminal block
The electric connections between the Bus Coupler and the Bus Terminals are automatically realized by
joining the components:
• The six spring contacts of the K-Bus/E-Bus deal with the transfer of the data and the supply of the Bus
Terminal electronics.
• The power contacts deal with the supply for the field electronics and thus represent a supply rail within
the bus terminal block. The power contacts are supplied via terminals on the Bus Coupler (up to 24V)
or for higher voltages via power feed terminals.
Power Contacts
During the design of a bus terminal block, the pin assignment of the individual Bus Terminals must
be taken account of, since some types (e.g. analog Bus Terminals or digital 4-channel Bus Termi-
nals) do not or not fully loop through the power contacts. Power Feed Terminals (KL91xx, KL92xx
or EL91xx, EL92xx) interrupt the power contacts and thus represent the start of a new supply rail.
PE power contact
The power contact labeled PE can be used as a protective earth. For safety reasons this contact mates first
when plugging together, and can ground short-circuit currents of up to 125A.