Pepperl+Fuchs KFD2-HMM-16 User manual

Manual
KFD2-HMM-16
PROCESS AUTOMATION
PEPPERL+FUCHS
HART Multiplexer Master
BA268F/00/en 02.03 Part No. 52017696

The general terms of delivery for products and services produced or provided by the electrical industry as
published by the Zentralverband Elektrotechnik und Elektroindustrie (ZVEI) e.V.
in its most recent edition as well as the supplementary proviso: "Extended property proviso" are applicable.
We at Pepperl+Fuchs feel obligated to contribute to the future;
this publication is, therefore, printed on paper bleached without the use of chlorine.

3
HART Multiplexer Master KFD2-HMM-16
Table of contents
Subject to reasonable modifications due to technical advances. Copyright Pepperl+Fuchs, Printed in Germany
Pepperl+Fuchs Group • Tel.: Germany (06 21) 7 76-0 • USA (330) 4 25 35 55 • Singapore 7 79 90 91 • Internet http://www.pepperl-fuchs.com
Part No.: 109143, Date of issue 29.11.2000
Table of contents
1INTRODUCTION ....................................................................................................................5
1.1 Explanation of the symbols used in the manual ......................................................................................5
1.2 Aim of the manual ........................................................................................................................................5
1.3 Intended use .................................................................................................................................................5
1.4 Responsibilities of the user ........................................................................................................................6
1.5 Marking .........................................................................................................................................................6
2PRODUCT DESCRIPTION .......................................................................................................7
2.1 HART multiplexer master ............................................................................................................................7
2.1.1 Delivery package ...........................................................................................................................................7
2.1.2 Accessories/Product family ............................................................................................................................7
2.1.3 Description of the hardware ...........................................................................................................................7
2.1.4 Galvanic isolation ...........................................................................................................................................9
2.1.5 Cabling for the analogue signals ...................................................................................................................9
2.1.6 Device function ..............................................................................................................................................9
2.1.7 Start-up sequence .......................................................................................................................................11
2.1.8 Operation .....................................................................................................................................................11
2.1.9 LED indicators .............................................................................................................................................12
2.1.10 Device parameter, parameterisation ............................................................................................................12
2.1.11 Connection to the service station (PC, DCS/Process control system) ........................................................13
2.1.12 DIP switch settings ......................................................................................................................................13
2.1.13 Connection and Connection Assignment of RS 485 ....................................................................................14
2.2 Description of the HART communication ................................................................................................15
2.3 System construction .................................................................................................................................16
2.3.1 System description ......................................................................................................................................16
2.3.2 Service station .............................................................................................................................................16
2.3.3 Integration in the operating software (Asset Management Systems) ..........................................................16
2.3.4 System construction with and without multiplexer slaves ............................................................................17
2.3.5 System structure with Flex-interface solutions ............................................................................................18
2.3.6 Structure with motherboard solutions ..........................................................................................................19
2.4 HART Multiplexer Slave ............................................................................................................................20
2.5 Slave connection .......................................................................................................................................20
3INSTALLATION ...................................................................................................................21
3.1 Storage and transportation .......................................................................................................................21
3.2 Unpacking ..................................................................................................................................................21
3.3 Installation ..................................................................................................................................................21
3.4 Electrical connection .................................................................................................................................21
3.4.1 General notes for connection .......................................................................................................................21
3.4.2 Location of electrical connections ................................................................................................................21
3.4.3 Note on electromagnetic compatability (EMC) ............................................................................................22
3.5 Dismantling, packaging and disposal .....................................................................................................22

HART Multiplexer Master KFD2-HMM-16
Table of contents
4Subject to reasonable modifications due to technical advances. Copyright Pepperl+Fuchs, Printed in Germany
Pepperl+Fuchs Group •Tel.: Germany (06 21) 7 76-0 •USA (330) 4 25 35 55 •Singapore 7 79 90 91 •Internet http://www.pepperl-fuchs.com
Part No.: 109143, Date of issue 29.11.2000
4COMMISSIONING ...............................................................................................................23
4.1 Commissioning check list ........................................................................................................................ 23
4.2 Data access to the connected transmitters ............................................................................................ 23
5DIAGNOSIS AND FAULT ELIMINATION .................................................................................24
5.1 General ....................................................................................................................................................... 24
5.2 LEDs ........................................................................................................................................................... 24
5.3 Status/Response code (Response code) ............................................................................................... 24
5.3.1 General ....................................................................................................................................................... 24
5.3.2 Structure of the first byte ............................................................................................................................. 24
5.3.3 Device status (structure of the second byte) ............................................................................................... 26
5.4 Extended device status ............................................................................................................................ 27
6APPENDIX .........................................................................................................................28
6.1 Supported commands .............................................................................................................................. 28
6.2 Terminal assignment of the 26 pin connector with analogue HART signals ...................................... 31
6.3 Literature ................................................................................................................................................... 32
6.4 Glossary ..................................................................................................................................................... 32

5
HART Multiplexer Master KFD2-HMM-16
Introduction
Subject to reasonable modifications due to technical advances. Copyright Pepperl+Fuchs, Printed in Germany
Pepperl+Fuchs Group •Tel.: Germany (06 21) 7 76-0 •USA (330) 4 25 35 55 •Singapore 7 79 90 91 •Internet http://www.pepperl-fuchs.com
Part No.: 109143, Date of issue 29.11.2000
1 Introduction
1.1 Explanation of the symbols used in the manual
1.2 Aim of the manual
This manual should enable the user to install the HART multiplexer master, to commission it and to maintain
it. It provides all the information required on status and fault messages and also provides a guide to fault
diagnosis and rectification.
1.3 Intended use
The HART multiplexer master KFD2-HMM-16 provides full HART access to up to 256 field devices and
hence operation with the conventional 4m A.. .2 0mA current loops. It thus acts as a transparent gateway
between the service station (PC, or process control system) and the transmitters.
The multiplexer can be used within Zone 2 hazardous areas or in the safe area. Power is provided by a 24 V
(nominal voltage) DC power supply. Connection to the process control system or PC is via an R S485
interface.
This symbol warns of danger. If the instruction given in this warning is not heeded the result
could be the injury or death of personnel and/or the severe damage or destruction of equipment.
This symbol advises of a possible failure. If the instruction given in this warning is not heeded,
the device and any plant or systems connected to it could develop a fault or even fail completely.
This symbol indicates important information.
In addition, the manual provides an introduction to HART communication. For additional infor-
mation, the attention of the user is directed to the bibliography in the appendix and to other lite-
rature on the subject, including the publications of the HART Communication Foundation
(www.hartcomm.org).
Where reference to the bibliography is made in this manual it is indicated thus: /3/.
The appendix also explains many terms and abbreviations used in this manual.
It should be stressed that the HART multiplexer master KFD2-HMM-16 is approved for use in
zone 2 and therefore may not be used in zone 0 or 1 hazardous areas. If the equipment is used
in conjunction with intrinsically safe or associated apparatus, then this use must take place in
front of the Ex-barrier (e. g. transmitter power supply device).
Reference should be made to the statement of conformity contained in TÜV 00 ATEX 1547 X.

HART Multiplexer Master KFD2-HMM-16
Introduction
6Subject to reasonable modifications due to technical advances. Copyright Pepperl+Fuchs, Printed in Germany
Pepperl+Fuchs Group •Tel.: Germany (06 21) 7 76-0 •USA (330) 4 25 35 55 •Singapore 7 79 90 91 •Internet http://www.pepperl-fuchs.com
Part No.: 109143, Date of issue 29.11.2000
1.4 Responsibilities of the user
In order to avoid damage, incorrect operation and equipment failures, the user must make himself ac-
quainted with the equipment and must have read and understood the manual before undertaking its instal-
lation and commissioning.
1.5 Marking
The following identification is affixed to the KFD2-HMM-16 multiplexer:
Pepperl+Fuchs GmbH
D-68307 Mannheim
KFD2-HMM-16
TÜV 00 ATEX 1547 X II 3G EEx n A II T4
Repairs to the device must only be undertaken by specialist personnel and in compliance with
the relevant regulations.
We strongly recommend that repairs are undertaken by the manufacturer. No guarantee claims
will be accepted by Pepperl+Fuchs GmbH resulting from improper repair work.

7
HART Multiplexer Master KFD2-HMM-16
Product description
Subject to reasonable modifications due to technical advances. Copyright Pepperl+Fuchs, Printed in Germany
Pepperl+Fuchs Group •Tel.: Germany (06 21) 7 76-0 •USA (330) 4 25 35 55 •Singapore 7 79 90 91 •Internet http://www.pepperl-fuchs.com
Part No.: 109143, Date of issue 29.11.2000
2 Product description
2.1 HART multiplexer master
2.1.1 Delivery package
Included in the delivery package of the device are:
•One device KFD2-HMM-16
•One product supplement (manual, data sheet, installation instruction)
2.1.2 Accessories/Product family
In addition to the HART multiplexer master, the following items from the HART multiplexer system family of
products are available from Pepperl+Fuchs:
•KFD0-HMS-16, HART multiplexer slave, for extending the HART channels
•KSD2-HC, HART RPI control module, for connecting the HART multiplexer to the RPI product family
•K-HM14, cable master ↔slave, for connecting the master with the slaves
•FI-***, HART flexible interface, handover interface of the analogue signals between transmitter, multiple-
xer and PLC/DCS (control system specific)
•MB-***, motherboard, carrier board for Ex-isolator module
•K-HM26, cable master/slave ↔FI-***/MB-***, for connection of master/slave with flexible interface FI-***
or motherboard MB-***, respectively
•Interface converter RS 485 ↔RS 232 (Telebyte Model No. 285), converter RS 485 ↔RS 232,
Pepperl+Fuchs order code: Telebyte Model 285M
2.1.3 Description of the hardware
The HART multiplexer can operate up to 256 analogue transmitters. The built-in slave unit operates the first
16 loops, and a maximum of a further 15 KFD0-HMS-16 slaves can be connected.
The external connections are shown in Figure 2.1 and Figure 2.2.
The power supply (2 4 VDC nominal voltage) is provided via the power rail or terminals 17 and18. The op-
tional slave units or the RPI control module are connected with the master via a 14-core flat cable (K-HM14).
Its connector is placed on the same housing side as the terminals for the R S485 interface and the voltage
supply. The analogue signals for each unit are connected separately via a 26-core cable. 16 leads are pro-
vided for the HART signals of the analogue instrument circuits, the other 10 are connected to ground. The
minimum load resistance of the analogue instrument circuits is 2 30Ω(min. load resistance in accordance
with the HART specification), the max. load resistance is 5 0 0Ω. Load resistances of up to 1000 Ωare pos-
sible, however, resistance values greater than 500 Ωcan interfere with the HART communication. The con-
nector for these connections is located on the top of the housing. A process control system or a PC can be
connected via a RS485 interface (terminals 13, 14 and 15). Up to 31 KFD2-HMM-16 can be operated on
one RS 485 interface. Terminals 19, 20 and 21 can be used to connect additional stations to the R S485
interface. The DIP-switch on the housing front is for the setting of the R S485 address and the baud rate.
The complete product family is described in the Pepperl+Fuchs product catalogues.
Please refer to the ordering instructions detailed in the catalogues.

HART Multiplexer Master KFD2-HMM-16
Product description
8Subject to reasonable modifications due to technical advances. Copyright Pepperl+Fuchs, Printed in Germany
Pepperl+Fuchs Group •Tel.: Germany (06 21) 7 76-0 •USA (330) 4 25 35 55 •Singapore 7 79 90 91 •Internet http://www.pepperl-fuchs.com
Part No.: 109143, Date of issue 29.11.2000
Figure 2.1: Block diagramm KFD2-HMM-16
Figure 2.2: Location of the plug connectors and controls and the indicators of the KFD2-HMM-16
26 pin connector
for up to
16 analog signal sources
14 pin connector
for up to
15 KFD0-HMS-16 devices
Micro processor
Multiplexer
Power supply Power Rail
RS 485
Repeater
17+ 18-
+ -
13 14 15 19 20 21
grd T- T+
Front view
LED red:
Fault signal
26 pin connector
LED orange:
operational
14 pin connector
LED green:
Power supply
Connectors RS 485
Power supply
1
26

9
HART Multiplexer Master KFD2-HMM-16
Product description
Subject to reasonable modifications due to technical advances. Copyright Pepperl+Fuchs, Printed in Germany
Pepperl+Fuchs Group •Tel.: Germany (06 21) 7 76-0 •USA (330) 4 25 35 55 •Singapore 7 79 90 91 •Internet http://www.pepperl-fuchs.com
Part No.: 109143, Date of issue 29.11.2000
2.1.4 Galvanic isolation
Thevoltage supply,theanalogue signals andthe RS 485 interfaceare galvanicallyseparated. Thisgalvanic
isolation is achieved through the use of transformers and opto couplers.
For the direct current components, the individual HART channels are isolated by means of capacitors. Thus
the 4 mA ... 20 mA signal is not affected.
Notwithstanding the common ground connection of the analogue signals from the masters/slaves, the gal-
vanic isolation of the current repeaters is secured if
•FI and MB boards are used, which are fitted with capacitors.
•KFD2-STC4-Ex1 or KFD2-STC4-Ex2 Ex isolation modules are used as current repeaters.
2.1.5 Cabling for the analogue signals
The individual I/O components of the HART product family are connected by a single 26-pin system plug
connector for the connection of the individual current repeaters (for plug pin assignmentsee section 6.2).
Pepperl+Fuchs provide specially developed connector units (HART interfaces type FI-***) for this purpose.
As required, the connection to these units can be via a system cable or even by means of conventional
screwconnections. If the current repeaters are mounted on a motherboard (MB-***), the connection is made
directly from the board to the multiplexer via a flat cable type K-HM26.
The control system is connected via a system specific connector of the motherboard or the Flex-interface.
Flex-interfaces with screw terminals are available for the purpose of individual wiring.
2.1.6 Device function
Channel number
The HART multiplexer master KFD2-HMM-16 provides 16 channels for the connection of "smart“transmit-
ters or control devices, which support digital communication in accordance with the HART specification. A
maximum of 15 additional KFD0-HMS-16 slaves can be connected, each of which in turn support 16 chan-
nels. Thus in a full assembly, a loop of 256 channels can be achieved with just one master. When using the
multiplexer master with the RPI product family, no slave units are necessary. On RPI, communication takes
place via the power rail.
Multiplexer table (module table)
The multiplexer master and the connected multiplexer slaves must be designated as 'available' in a multi-
plexer table (command 157). Only those modules defined as 'available' in this table are used in the commu-
nication process. The multiplexer table consists of 16 bit, one for each possible multiplexer address
(default: module 0 (master) and 1 activated).
The connected current repeaters are galvanically interconnected unilaterally through the com-
mon ground connection of the analogue signals.
If the galvanic isolation is to be properly maintained, the individual ground cables must be isola-
ted by capacitors. Suitable Fl and MB boards can be supplied byPepperl+Fuchs for this pur-
pose.
The software functions described in this section are normally integrated into the operating soft-
ware for the servicing station, i.e. the functions are not generally (de-)activated via the descri-
bed HART commands. In contrast the operating software uses functions (menu commands) to
control these procedures. However the basic HART commands are described as well, because
the functions may be named different in the various operating softwares and the basic function
may not be obvious. Information on the supported commands can be found in section 6.1.

HART Multiplexer Master KFD2-HMM-16
Product description
10 Subject to reasonable modifications due to technical advances. Copyright Pepperl+Fuchs, Printed in Germany
Pepperl+Fuchs Group •Tel.: Germany (06 21) 7 76-0 •USA (330) 4 25 35 55 •Singapore 7 79 90 91 •Internet http://www.pepperl-fuchs.com
Part No.: 109143, Date of issue 29.11.2000
Interface
In this way, the multiplexer master acts as a transparent gateway between the service station (typically a
PC with suitable software, see section 2.3.2) and the field devices. The service station is able to communi-
cate with up to 31 multiplexer master via up to 38400 baud R S485 connection. Because each master is
able to communicate with 256 field devices, up to 7936 field devices are controlable over a singl e RS485
interface.
HART
As a digital communication system for servicing and configuration purposes, the HART protocol is suppor-
ted by many field devices with conventional analogu e 4m A. . .2 0mA current loops. The HART signal is
thus modulated on the analogue current as an FSK signal (see section 2.2). The modulator/demodulator
circuitry (Modem) required for this is integrated in the multiplexer. Only one HART transmitter can be con-
nected at each multiplexer HART connection (no "multidrop“functionality).
Special procedures in respect to HART communication:
•On the host side (RS 485) always the long frame address is used (except for command 0).
•On the field devices side, either the short address or the long frame address is used, depending on
necessity.
•The operating modes "Primary Master“and "Secondary Master" and the corresponding time responses
are supported on the field device side.
•On the host side, only the commands 0 ... 3 and 1 1. . .13 are accepted from the secondary host. Other
commands are not accepted/are ignored.
•Commands to connected field devices are only accepted by the primary host.
•Extended messages and messages in the Burst Mode are recognised and used, but not generated by
the multiplexer itself.
•An answer buffer is available for a delayed message response. This can be used to intermediately store
a message, the command for which requires a long execution time.
Loop construction/REBUILD (Software function)
On power-up, the device searches the multiplexers in the multiplexer table for the connected HART field
devices (commands 0 and 41) and generates the internally required access tables. This function can also
be carried out by the connected service station, as is necessary, for example, in communication with newly
connected HART field devices. The duration of this function depends on the number of connected multiple-
xer slaves and HART field devices and also on the type of loop search (see command 153) and the permis-
sible number of message repeats. With 16 HART devices (e.g. by using only one master without slaves) the
duration is between 1 5s and 3 0s. The number of permissible message repeats is set to "2" in the factory
setting and the loop search type to "single analogue".
During the REBUILD phase, only certain read commands are accepted from the service station (commands
0, 1, 2, 3, 11, 12, 13, 48, and 129). All other commands are followed by the response "Busy" (Code 32, see
section 5.3.2), until the REBUILD phase ends.
Cyclic data interrogation/SCAN (software function)
The multiplexer can read cyclic data from up to 31 transmitters. In this case the SCAN option must be set
for the transmitter (command 137) and the SCAN function activated in the multiplexer (command 149,
function 1). Which data is transferred is determined by the "SCAN command" option (command 147).
If the SCAN function is activated, the transmitters, on which the SCAN option is activated are regularly chek-
ked for data. In this case, the SCAN command is executed, with which one or more variables are read from
the transmitter. If a field device does not respond, it is designated as having "disappeared" (see command
129), but it remains in the search list (i. e., it is searched for again on the next run sequence). If a device
has disappeared, but responds correctly on the next search command, it is then listed as "appeared". If,
instead of this, another device has answered, then the status "mismatched" is assigned.
1. Command 4 is additionally used on transmitters which only support the old HART specifications up to 4.

11
HART Multiplexer Master KFD2-HMM-16
Product description
Subject to reasonable modifications due to technical advances. Copyright Pepperl+Fuchs, Printed in Germany
Pepperl+Fuchs Group •Tel.: Germany (06 21) 7 76-0 •USA (330) 4 25 35 55 •Singapore 7 79 90 91 •Internet http://www.pepperl-fuchs.com
Part No.: 109143, Date of issue 29.11.2000
Variation on the SCAN function (special SCAN function)
The multiplexer offers in addition a second SCAN function. With this special SCAN function (command 149,
function 2) an additional parameter is used, which defines the minimum length of the expected number of
data bytes. This can be different for each current loop, but must be set for each current loop that is to be
scanned.
The SCAN function itself takes place as above, however, the response of the transmitter is compared with
the expected data length. If the length of the response is less than the set minimum data length, the answer
is rejected. If the minimum length is 0, the answer is always saved.
Delay on channel change/Loop switch delay (software function when used with RPI)
If the HART multiplexer is used with the RPI HART control module KSD2-HC, a pause time must be inserted
when the multiplexer channel is changed. This pause time isnecessary, since the RPI HART control module
has to monitor the communication channel of the multiplexer and recognise the channel change. This pause
time can be set by means of command 161.
All the functions at a glance
The following list gives all the functions once again at a glance:
•16 channels, extendable to 256 channels by the connection of up to 15 KFD0-HMS-16 slaves.
•Up to 7936 loops per interface
•Automatic search of all existing HART field devices (REBUILD)
•Facility for self-standing cyclic interrogation of the HART variables (SCAN)
•Acts as a primary or secondary master
•Fast RS 485 interface (multidrop) with up to 38400 baud
•Integrated Modem
•Removable terminals
•Supply via power rail
•Approval for zone 2
2.1.7 Start-up sequence
Following connection of the power supply, the device executes an initialisation procedure with self test. The
function is indicated by a flashing green LED, any errors detected are indicated by a red LED. Next a search
is made of the multiplexers in the multiplexer table (command 157) for available HART compatible field
devices (REBUILD). This function is indicated by a flashing orange LED. The REBUILD function can also
be started via the service station, e. g. in order to include connected transmitters in the communication
process during the operating phase. The duration of this function is dependent on the number of connected
transmitters, multiplexer slaves and message repeats in the case of errors, or if an interrogation has not
been answered. The factory setting for the number of repeats is "2". The search duration for this lies
between approx. 30 s and several minutes (full structure).
In addition, transient data are set to their pre-setting. Non-volatile stored data are retained. see section
2.1.10.
2.1.8 Operation
The multiplexer master KFD2-HMM-16 also functions as a HART device (see also section 2.1.10). How-
ever, due to the incorporation into the operating software of the service station (see section 2.3.3), this
remains concealed from the user. The HART commands that are supported by the multiplexer can be found
in section 6.1.
For HART communication with the transmitters, the commands of the service station are passed through
without modifications.

HART Multiplexer Master KFD2-HMM-16
Product description
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Part No.: 109143, Date of issue 29.11.2000
2.1.9 LED indicators
The device has three LEDs, located on the front of the housing.
The meaning of these LEDs is given in the following table:
2.1.10 Device parameter, parameterisation
For the identification and programming of the multiplexer master, this contains - as do other HART field
devices - specific parameters that are in the non-volatile memory. The following list shows these parameters
and how the programming must be carried out.
•Unambiguous device identification (see commands 0, 11)
The deviceidentification provides information about the device (type,type-ID, serialnumber and revision
numbers) and the manufacturer and cannot be changed.
•Message (see commands 12 and 17)
An arbitrary 32 character long item of text can be stored in the device under this parameter.
•Tag, description and date (see commands 13 and 18)
A tag (8 characters), description (16 characters) and a date, can be saved under these parameters.
•The number of preambles in message responses (see command 59)
This parameter is used to establish how many preambles are inserted in message responses. The pre-
setting is 4, the setting range is 2 ... 20.
•Number of message repeats (retry) (see commands 144 and 145)
The number of message repeats can be separately set for the repeats in the case of communication
errors and for the response code "Busy" (see section 5.3.2).
The range of adjustment is 0.. .11 repeats. In the case of communication errors, the pre-setting is 2, in
the case of the response code "Busy" it is 0.
•SCAN command (see section 2.1.6 and commands 146 and 147)
Of the available SCAN parameters, only the SCAN command is stored by non-volatile means. It signifies
which HART command (1, 2 or 3) is to be sent to the transmitter as the SCAN command.
•Master type (primary or secondary master) (see command 151)
This controls the priority for access to the HART field devices. A primary master always initiates a con-
nection with a field device. A secondary master initiates a connection to a field device through an arbi-
tration function (i.e. only when the primary master does not achieve access). The pre-setting of the
multiplexer is "Primary Master". A typical example of a secondary master is a hand-held operating
device.
•Loop type search (command 153)
At present, the multiplexer does not support a multidrop with HART, i. e. only one HART field device is
connected to each HART channel. With loop construction (REBUILD, see above )the connected field
devices are either always searched on the short address 0 ("single analogue"), or, in preparation for
multidrop, on the short addresses 0 ... 15, in which the first one found is addressed ("single unknown").
•Module table (see section 2.1.6 and command 157)
•Delay time on channel change (loop-switch delay) (see section 2.1.6 and command 161)
Colour Meaning
Red Error indications (detected during the initialisation phase)
Green Operating indications
Orange HART communication with a field device
During the initialisation phase, the green LED flashes, the other two are off.
During the REBUILD function, the green LED is ON and the orange flashes.
If all three LEDs flash one after the other, the DIP switch 1 (test) is in the "ON" position. Set the
switch to "OFF“ and repeat the commissioning.

13
HART Multiplexer Master KFD2-HMM-16
Product description
Subject to reasonable modifications due to technical advances. Copyright Pepperl+Fuchs, Printed in Germany
Pepperl+Fuchs Group •Tel.: Germany (06 21) 7 76-0 •USA (330) 4 25 35 55 •Singapore 7 79 90 91 •Internet http://www.pepperl-fuchs.com
Part No.: 109143, Date of issue 29.11.2000
2.1.11 Connection to the service station (PC, DCS/Process control system)
The connection to the service station or to the control system is made via a multidrop able RS 485 interface.
The baud rate of this interface can be set to 9600, 19200 or 38400 baud via the DIP switches 2 and 3 (see
section 2.1.12). The device address for the communication via RS 485 is set by the DIP switches 4 to 8 (see
section 2.1.12).
2.1.12 DIP switch settings
8 DIP switches are located on the top of the device. DIP switch 1 is used by the manufacturer for testing the
device and must therefore always be set to "OFF".
DIP switches 2 and 3 determine the baud rate of the RS 485 interface.
DIP switches 4 to 8 determine the RS485 address. A value is assigned to each of the individual DIP
switches for this purpose. The resulting address is given by the addition of the set values.
Condition on delivery
When setting the address, care should be taken to ensure that no address is assigned more
than once, since this can lead to communication errors or even communication failure.
The adjusted baud rate must comply with the service station.
DIP switch 1Meaning
Setting OFF Normal status (LED test de-activated)
ON LED test activated; all three LEDs flash one after the other
DIP switch 2 3 Meaning
Setting
OFF OFF 9600 Baud
OFF ON 19200 Baud
ON OFF 38400 Baud
ON ON Not permitted
DIP switch 4 5 6 7 8 Meaning
Setting
ON Value 16
ON Value 8
ON Value 4
ON Value 2
ON Value 1
Example: OFF ON ON OFF ON address = 8 + 4 + 1 = 13
To accept the values set on the DIP switches, the device must be isolated briefly from power
supply.
DIP switch 1 2 3 4 5 6 7 8 Meaning
Setting OFF OFF OFF OFF OFF OFF OFF OFF Manufacturer test de-activated Baud rate 9600 baud
RS 485 address 0
The address 0 is set on the device when delivered. Care should be taken that no address is
assigned more than once.

HART Multiplexer Master KFD2-HMM-16
Product description
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Part No.: 109143, Date of issue 29.11.2000
2.1.13 Connection and Connection Assignment of RS 485
Connector assignment of the removable terminals:
In accordance with the RS 485 specification up to 32 stations ("multidrop") can be connected to a up to
1200 m cable (for data rates less than 100 kBaud). Pepperl+Fuchs recommends that this length of cable is
not exceeded. Even though problems seldom occur at these data rates, screened twisted two-wire cabling
should be used.
In addition a terminating resistor should be connected to each end of the R S485 cable. If the multiplexer
master is such a device, i. e. the RS 485 cable ends here and is not routed to other devices, then the second
available connection terminal for the RS 485 can be used for the connection of a terminating resistance.
The terminating resistor terminates the cables with its characteristic impedance. At minimal baud rates and
with short lengths of cable, in practice quite often no terminating resistors are used. If communication errors
arise, or if these are to be positively excluded from the outset, terminating resistors typically of
120 Ω... 220 Ωshould be used. Such can, for example, be connected between terminals 20 and 21.
Terminal Description Meaning
13, 19 Screen Cable screening
14, 20 RxD/TxD + (RS 485 B) RS 485 differential signal
15, 21 RxD/TxD - (R S485 A)
If the screen is grounded, the grounding should only be connected to one end of the cable, in
order to avoid equipotential bonding currents. However, in all cases, existing guidelines and
regulations must be observed.
To connect a standard PC with a R S232 interface an interface converter R S485 to R S232 is
required. A converter that has been tested and recommended by Pepperl+Fuchs is manufactu-
red by Telebyte (Telebyte Model No. 285). This can be obtained fromPepperl+Fuchs under the
part number "Telebyte Model 285M“.
If an interface converter is used, a terminating resistor should be connected to the converter
and another to the other end of the cable.

15
HART Multiplexer Master KFD2-HMM-16
Product description
Subject to reasonable modifications due to technical advances. Copyright Pepperl+Fuchs, Printed in Germany
Pepperl+Fuchs Group •Tel.: Germany (06 21) 7 76-0 •USA (330) 4 25 35 55 •Singapore 7 79 90 91 •Internet http://www.pepperl-fuchs.com
Part No.: 109143, Date of issue 29.11.2000
2.2 Description of the HART communication
The HART1protocol is supported by many conventional 4 mA ... 20 mA field devices, which thus enable
digital communication for configuration and servicing purposes. Many device parameters and also the mea-
sured values themselves can thus be digitally transferred to and from the device. This digital communication
runs in parallel with th e 4m A. . .2 0mA signal on the same cable. This is possible through a current modu-
lation, which is superimposed on the user signal.
Figure 2.3: The modulated HART-Signal
HART is a master-slave protocol: a field device does only respond when requested (except in "Burst mo-
de"). The message duration is several hundred milliseconds, so that between two and three messages can
be transferred per second.
On HART, there are three groups of commands:
•The "Universal" commands; these must be supported by all field devices;
•the "Common practice" commands; these are pre-defined commands, suitable for many field devices,
which, if they are supported by the device, must be implemented in the pre-defined form;
•device-specific commands; these are commands, which are particularly suitable for this field device.
The HART multiplexer contains commands in all three groups. Details of the supported commands are
given in section 6.1.
1. HART = Highway Addressable Remote Transducer
-0,5 mA
+0,5 mA
0
1200 Hz 2200 Hz
"1" "0"
20 mA
Analogue
signal
C
R
CRCR
4 mA C = Command
R = Response
Time (seconds)
FSK signal
The high frequency HART signal consists of
the sinusoidal frequencies 1200 Hz and
2200 Hz. This signal has an average value of
zero, so that it does not affect the analogue
signal. It is removed by standard analogue
input circuit filtering.

HART Multiplexer Master KFD2-HMM-16
Product description
16 Subject to reasonable modifications due to technical advances. Copyright Pepperl+Fuchs, Printed in Germany
Pepperl+Fuchs Group •Tel.: Germany (06 21) 7 76-0 •USA (330) 4 25 35 55 •Singapore 7 79 90 91 •Internet http://www.pepperl-fuchs.com
Part No.: 109143, Date of issue 29.11.2000
2.3 System construction
2.3.1 System description
In process engineering plants, there are many field devices distributed over a large area. The characteristic
values of these field devices must be monitored, for example, in the context of ISO 9000 and recorded and
adapted to changes in process parameters.
The HART multiplex system from Pepperl+Fuchs enables online communication between a PC and "smart"
field devices that support the HART protocol.
Smart transmitters and intelligent valve positioners enable information such as measurement range, tag
number, ID number and manufacturer to be stored in the field device itself. Access to these data is usually
obtained using a handheld terminal. This means, that when changes to information are required, connection
to the field device must be carried out "By hand".
When specific data has to be recorded in the context of quality assurance - in accordance with ISO 9000 -
this means that there is an increased demand on the process control system or the DCS. For example, the
data has to be cyclically interrogated and then stored by the system in a database.
The HART multiplex system from Pepperl+Fuchs provides the coupling between the PC and the intelligent
"HART-capable" field devices. All access to the field device takes place in parallel with the transfer of the
4 mA ... 20 mA measuring signal and therefore has no affect on the processing of measured values by the
process control system.
The system thus provides a subordinate service interface. It is also possible to obtain measured values
through the HART multiplex system. On field devices, which are installed in hazardous areas, the coupling
takes place on the safe area side of the current repeaters.
Pepperl+Fuchs can supply the appropriate KFD2-STC4-Ex1/KFD2-STC4-Ex2 smart current repeaters and
KFD2-SCD-Ex1.32, KFD2-SCD-Ex1.LK smart isolated transformers. Similarly, the HART multiplex system
can also be connected to other smart Ex-isolation stages. This means that existing systems can be expan-
ded very easily, thus taking full advantage of the HART communication system.
The system comprises a max.of 31 HART multiplexer masters, which are connected to the PCvia a RS 485
interface. Each HART multiplexer master can control up to 15 HART multiplexer slaves. Each multiplexer,
irrespective of master or slave, can connect up to 16 transmitters.
Thus one PC can be used to address up to 7936 field devices for the exchange of data. Operation using a
handheld terminal also remains possible, since the HART protocol accepts 2 masters in one system, i. e.
PC and handheld terminal.
2.3.2 Service station
Besides the control system a PC is frequently used as the service station, with which the parameter
functions or data logging functions can be carried out. Operating programs for the PC are available from
various manufacturers (see section 2.3.3) to provide the necessary back-up for this purpose.
However, in some cases the communication is provided by a process control system via a RS 485 interface
direct (via the HART multiplexer) to the field devices without a connected service station. But the low speed
of the HART communication imposes limitations on this method of operation.
2.3.3 Integration in the operating software (Asset Management Systems)
The full potential of the HART multiplexer System is realised through integration in modern Asset Manage-
ment Systems such as PACTware (open source), SIMATIC PDM (Siemens), AMS (Fisher-Rousemount),
Cornerstone (Applied System Technologies) and Valve Manager (Neles Automation). These operating
tools combine the device functions of the multiplexer in the form of menu commands in a unified interface
providing a very convenient method of operation. The presentation and description of the functions in the
individual operating tools can be very different, however; thus a generally applicable presentation is not
possible here.
Information on the configuration, parameter assignment, operation and diagnostics options of
the multiplexer is provided in the documentation accompanying the various operating tools.

17
HART Multiplexer Master KFD2-HMM-16
Product description
Subject to reasonable modifications due to technical advances. Copyright Pepperl+Fuchs, Printed in Germany
Pepperl+Fuchs Group •Tel.: Germany (06 21) 7 76-0 •USA (330) 4 25 35 55 •Singapore 7 79 90 91 •Internet http://www.pepperl-fuchs.com
Part No.: 109143, Date of issue 29.11.2000
PACTware
PACTware™is the first open source Process Automation Configuration Tool with an open FDT interface
(Field Device Tool). For the first time this enables all field buses and field devices in a system, independent
of the manufacturer, to be configured and assigned parameters using a single engineering tool.
Representative example on the basis of PACTware
The PACTware user interface is divided into two parts: The project tree is located in the left part; the data
and input fields being represented in the right.
The system structure is represented in the project tree. Above the HART multiplexer there is a HART driver
and above that a host system (PC). All the connected multiplexer slaves are to be found under the HART
multiplexer master and also the internal one that is indicated as having the slave address 0.
Under these slave units there are the HART-compatible field devices.
2.3.4 System construction with and without multiplexer slaves
In a system structure without multiplexer slaves, only one multiplexer master is used. The arrangement is
restricted to 16 HART channels. With two to three messages per second, the system cycle time can be up
to one minute.
In a system structure with multiplexer slaves, one multiplexer master and up to 15 slaves are used. The
number of channels per slave is extended by 16, so that in the fully-developed structure 256 HART channels
are available. With two to three messages per second, the system cycle time is several minutes.
Figure 2.4: Multiplexer system structure
The connection between the field devices and the control system is the same in both cases and can take
place via motherboards or Flex-Interfaces (see section 2.3.5 and 2.3.6).
Converter
Power Rail Insert 26 way ribbon cable
14 way ribbon cable DIN Rail
Up to 31 HART Mux Masters
Up to 15 HART Mux Slaves per Master
HART connector to Flexible Interface Board or Motherboard
HART signals from smart field instruments -
16 smart field devices per Slave and Master
24 VDC
KFD0-HMS-16
KFD2-EB2
4AT
!
KFD2-HMM-16
ON
13 14 15
19 20 21 16 17 18
ON
KFD0-HMS-16
78 9
10 11 12
Management
Software
RS 232
RS 485
RS 485

HART Multiplexer Master KFD2-HMM-16
Product description
18 Subject to reasonable modifications due to technical advances. Copyright Pepperl+Fuchs, Printed in Germany
Pepperl+Fuchs Group •Tel.: Germany (06 21) 7 76-0 •USA (330) 4 25 35 55 •Singapore 7 79 90 91 •Internet http://www.pepperl-fuchs.com
Part No.: 109143, Date of issue 29.11.2000
2.3.5 System structure with Flex-interface solutions
For general purpose applications, Pepperl+Fuchs offers Flex-interfaces in various versions. The HART con-
nection for one multiplexer is common to all versions. The connections for the maximum of 16 field devices
are provided as screw terminals or in the form of Pepperl+Fuchs system connectors for cable tree installa-
tion. The connections for the control system are likewise either provided as screw terminals or as control
system-specific connectors. Such a system is presented in Figure 2.5.
The distinguishing characteristics of the FI-*** in detail:
•Power feed option (also redundant), switchable for each individual module.
•Fuses
•250 Ωresistance
•Control system-specific connector (also redundant)
•Screw terminals/System connector
Figure 2.5: System with Flex-interface
KFD0-HMS-16
KFD2-HMM-16
ON
13 14 15
19 20 21 16 17 18
ON
Management
Software
Slave Master
RS 485
Up to 16 field devices
or
Process control system
Flex-interface
Service station
Connection
via system
connector

19
HART Multiplexer Master KFD2-HMM-16
Product description
Subject to reasonable modifications due to technical advances. Copyright Pepperl+Fuchs, Printed in Germany
Pepperl+Fuchs Group •Tel.: Germany (06 21) 7 76-0 •USA (330) 4 25 35 55 •Singapore 7 79 90 91 •Internet http://www.pepperl-fuchs.com
Part No.: 109143, Date of issue 29.11.2000
2.3.6 Structure with motherboard solutions
For applications in hazardous areas, motherboard solutions are employed. Motherboards serve as carriers
for Ex-isolation modules, such as current repeaters and isolated transformers and have connections both
for power supply, one or more HART system connectors suitable for the family of multiplexer devices and
a control system-specific connector for direct connection to the control system. Such a system is shown in
Figure 2.6.
The distinguishing characteristics of the MB-*** in detail:
•Power feed (also redundant) with fuses and LEDs
•250 Ωresistance
•Control system-specific connector (also redundant)
•Control system-specific arrangement of the Ex-isolation modules (Number and type)
Figure 2.6: System with motherboard
KFD2
-
STC4-Ex
2
PWR
7 8
10
13 14
1 2
3
4
KFD2
-
STC4-Ex
2
PWR
7 8
10
13 14
1 2
3
4
KFD2
-
STC4-Ex
2
PWR
7 8
10
13 14
1 2
3
4
KFD2
-
STC4-Ex
2
PWR
7 8
10
13 14
1 2
3
4
KFD2
-
STC4-Ex
2
PWR
7 8
10
13 14
1 2
3
4
KFD2
-
STC4-Ex
2
PWR
7 8
10
13 14
1 2
3
4
KFD2
-
STC4-Ex
2
PWR
7 8
10
13 14
1 2
3
4
KFD2
-
STC4-Ex
2
PWR
7 8
10
13 14
1 2
3
4
KFD0-HMS-16
KFD2-HMM-16
ON
13 14 15
19 20 21 16 17 18
ON
Management
Software
Ex
Slave Master
RS 485
Up to 16 field devices
or
supply
Redundant
Power supply
Motherboard
with isolation modules
Process control system
Service station
Connection
via system
connector

HART Multiplexer Master KFD2-HMM-16
Product description
20 Subject to reasonable modifications due to technical advances. Copyright Pepperl+Fuchs, Printed in Germany
Pepperl+Fuchs Group •Tel.: Germany (06 21) 7 76-0 •USA (330) 4 25 35 55 •Singapore 7 79 90 91 •Internet http://www.pepperl-fuchs.com
Part No.: 109143, Date of issue 29.11.2000
2.4 HART Multiplexer Slave
The HART multiplexer slave is supplied from the HART multiplexer master via the 14-core flat cable. The
contacting of the flat cable is provided via IDC connectors, so that the cable can be tapped at any position.
By this means, the power supply and data cables are looped on from station to station. The address 1 ... 15
is set via a 16-step rotary switch. Address 0 is reserved for the multiplexer master and must therefore not
be used. If a number of slaves are operated on the KFD2-HMM-16, different addresses must be assigned.
The sequence therefore plays no role in this.
The analogue signals are fed via a 26 core flat cable into the KFD0-HMS-16. 16 of these are intended for
the HART signal of the analogue instrument circuit (the remaining 10 are to ground) (for the assignment,
see section 6.2).
The minimum load resistance of the analogue measuring circuit is 23 0Ω(minimum load impedance in
accordance with HART specification), the maximum resistive load being 500 Ω. Load resistances of up to
1000 Ωare possible, however, resistance values greater than 50 0Ωcan interfere with the HART commu-
nication.
2.5 Slave connection
HART multiplexer masters and slaves must be connected together via a separate K-HM14 flat cable.
The length of cable required should be stated when ordering. Hence the wiring of the HART multiplexer is
significantly simplified and the danger of wiring faults is excluded.
1
26
FrontView
Rotary switch
26 pin
Connector
14 pin
Connector
Housing type A1
(see system description)