Siemens SITRANS F User manual

SITRANS F
Communication Modules
Modbus RTU RS485
Operating Instructions •06/2010

Introduction 1
Safety notes
2
Hardware Installation
3
SITRANS F
Connecting 4
Communication Modules
Modbus RTU RS485 System integration 5
Functions codes
6
Operating Instructions 7
Technical data
Modbus holding registers
A
Appendix
B
A
dd-on module for use with transmitter types
SITRANS F M MAG 6000, SITRANS F M MAG 6000 I
and SITRANS F M MASS 6000.
06/2010
A5E00753974-04

Legal information
Warning notice system
This manual contains notices you have to observe in order to ensure your personal safety, as well as to prevent
damage to property. The notices referring to your personal safety are highlighted in the manual by a safety alert
symbol, notices referring only to property damage have no safety alert symbol. These notices shown below are
graded according to the degree of danger.
DANGER
indicates that death or severe personal injury will result if proper precautions are not taken.
WARNING
indicates that death or severe personal injury may result if proper precautions are not taken.
CAUTION
with a safety alert symbol, indicates that minor personal injury can result if proper precautions are not taken.
CAUTION
without a safety alert symbol, indicates that property damage can result if proper precautions are not taken.
NOTICE
indicates that an unintended result or situation can occur if the corresponding information is not taken into
account.
If more than one degree of danger is present, the warning notice representing the highest degree of danger will
be used. A notice warning of injury to persons with a safety alert symbol may also include a warning relating to
property damage.
Qualified Personnel
The product/system described in this documentation may be operated only by personnel qualified for the specific
task in accordance with the relevant documentation for the specific task, in particular its warning notices and
safety instructions. Qualified personnel are those who, based on their training and experience, are capable of
identifying risks and avoiding potential hazards when working with these products/systems.
Proper use of Siemens products
Note the following:
WARNING
Siemens products may only be used for the applications described in the catalog and in the relevant technical
documentation. If products and components from other manufacturers are used, these must be recommended
or approved by Siemens. Proper transport, storage, installation, assembly, commissioning, operation and
maintenance are required to ensure that the products operate safely and without any problems. The permissible
ambient conditions must be adhered to. The information in the relevant documentation must be observed.
Trademarks
All names identified by ® are registered trademarks of the Siemens AG. The remaining trademarks in this
publication may be trademarks whose use by third parties for their own purposes could violate the rights of the
owner.
Disclaimer of Liability
We have reviewed the contents of this publication to ensure consistency with the hardware and software
described. Since variance cannot be precluded entirely, we cannot guarantee full consistency. However, the
information in this publication is reviewed regularly and any necessary corrections are included in subsequent
editions.
Siemens AG order number: A5E00753974 Copyright © Siemens AG 2010.
Industry Sector Ⓟ 08/2010 Technical data subject to change
Postfach 48 48
90026 NÜRNBERG
GERMANY

Modbus RTU RS485
Operating Instructions, 06/2010, A5E00753974-04 3
Table of contents
1 Introduction................................................................................................................................................ 5
1.1 Purpose of the Operating Instructions ...........................................................................................5
1.2 Document history ...........................................................................................................................5
1.3 Modbus RTU technology ...............................................................................................................6
1.4 Further Information ........................................................................................................................7
2 Safety notes............................................................................................................................................... 9
2.1 Installation in hazardous area........................................................................................................9
3 Hardware Installation ...............................................................................................................................11
3.1 MAG/MASS 6000 IP67 or 19"......................................................................................................11
3.2 MAG 6000 I..................................................................................................................................12
3.3 MASS 6000 Ex d..........................................................................................................................13
4 Connecting .............................................................................................................................................. 17
4.1 Wiring...........................................................................................................................................18
5 System integration................................................................................................................................... 19
5.1 Function check.............................................................................................................................19
5.2 Navigating the Modbus display menu..........................................................................................20
6 Functions codes ...................................................................................................................................... 23
6.1 Modbus Commands.....................................................................................................................23
6.2 Read coils ....................................................................................................................................24
6.3 Read multiple registers ................................................................................................................26
6.4 Write single coil............................................................................................................................28
6.5 Write multiple registers ................................................................................................................29
6.6 Report slave ID command ...........................................................................................................32
6.7 Exception handlng .......................................................................................................................33
7 Technical data ......................................................................................................................................... 35
A Modbus holding registers......................................................................................................................... 37
A.1 Process data ................................................................................................................................37
A.2 MODBUS driver settings..............................................................................................................38
A.3 MODBUS application settings......................................................................................................39
A.4 Basic settings...............................................................................................................................40
A.5 Totalizer .......................................................................................................................................42
A.6 Output ..........................................................................................................................................43

Table of contents
Modbus RTU RS485
4 Operating Instructions, 06/2010, A5E00753974-04
A.7 External input .............................................................................................................................. 50
A.8 Sensor characteristics................................................................................................................. 51
A.9 Product identity ........................................................................................................................... 52
A.10 Service info ................................................................................................................................. 52
A.11 Display settings ........................................................................................................................... 53
A.12 Flowmeter status......................................................................................................................... 57
B Appendix.................................................................................................................................................. 59
B.1 Units ............................................................................................................................................ 59
B.2 Units and point positioners.......................................................................................................... 59
B.3 Modbus Coils .............................................................................................................................. 64
B.4 Error information ......................................................................................................................... 66
B.5 Run indicator ...............................................................................................................................67
B.6 CRC calculation .......................................................................................................................... 68
B.7 Data type mapping ...................................................................................................................... 71
B.8 Float definition............................................................................................................................. 71
Glossary .................................................................................................................................................. 73
Index........................................................................................................................................................ 75

Modbus RTU RS485
Operating Instructions, 06/2010, A5E00753974-04 5
Introduction 1
1.1 Purpose of the Operating Instructions
Purpose
The Operating Instructions provide all information necessary for the installation and use of
the Modbus RTU add-on module (FDK-085U0234), intended for use with the Siemens Flow
Instruments USM-II family of transmitters presently including SITRANS F M MAG 6000 and
SITRANS F C MASS 6000.
Basic knowledge required
The instructions are not intended to be a complete tutorial on the Modbus RTU protocol, and
it is assumed the end user already has a general working knowledge of Modbus RTU
communication, especially in respect of master station configuration and operation. However
an overview is included in the following section to explain some fundamental aspects of the
protocol.
See also
For more information about SITRANS F C and SITRANS F M transmitters and sensors,
please refer to the appropriate Operating Instructions available on the flowdocumentation
homepage (http://www.siemens.com/flowdocumentation) or on the SITRANS F literature CD-
ROM.
1.2 Document history
The contents of these instructions are regularly reviewed and corrections are included in
subsequent editions. We welcome all suggestions for improvement.
The following table shows the most important changes in the documentation compared to
each previous edition.
Edition Remarks
06/2010 Revision 04: Contents restructured

Introduction
1.3 Modbus RTU technology
Modbus RTU RS485
6 Operating Instructions, 06/2010, A5E00753974-04
1.3 Modbus RTU technology
Modbus RTU is an open, serial (RS-232 or RS-485) protocol based on master/slave or
client/server architecture. The protocol interconnects field equipment such as sensors,
actuators, and controllers and is widely used in both process and manufacturing automation.
The fieldbus environment is the base level group of digital networks in the hierarchy of plant
networks.
Features
The SITRANS F Modbus RTU Communication modules comply with the MODBUS Serial
Line Protocol. Among other things this implies a Master-Slave protocol at level 2 of the OSI
model. A node (the master) issues explicit commands to one of the slave-nodes and
processes responses. Slave nodes will not transmit data without a request from the master
node, and do not communicate with other slaves.
Modbus is a mono Master system, which means that only one Master can be connected at
the time.
Communication modes
Two modes of communication are possible, Unicast and Broadcast.
● In unicast mode the Master sends a request to a specific Slave device, and waits a
specified time for a response.
response
Master
Slave Slave Slave
request
Figure 1-1 Unicast Communication Mode
● In Broadcast mode the master sends out a request to address "0", which means that the
information is for all Slave devices on the network. In Broadcast mode there is no
response from the Slave devices.
Master
Slave Slave Slave
request
Figure 1-2 Broadcast Communication Mode

Introduction
1.4 Further Information
Modbus RTU RS485
Operating Instructions, 06/2010, A5E00753974-04 7
Modbus Frame
The Modbus frame is shown below, and is valid for both requests and responses.
Table 1- 1 Modbus Frame
SLAVE ADDRESS FUNCTION MODE DATA CRC
1 Byte 1 Byte 0 ... 252 Bytes 2 Bytes
References
For further information, please refer to the following specification and guidelines available at
the Modbus Organisation (http://www.modbus.org/) Website
1. Serial Line Specification & Implementation guide v. 1.0
2. Application Protocol Specification v. 1.1
1.4 Further Information
The contents of these Operating Instructions shall not become part of or modify any prior or
existing agreement, commitment or legal relationship. All obligations on the part of Siemens
AG are contained in the respective sales contract which also contains the complete and
solely applicable warranty conditions. Any statements contained herein do not create new
warranties or modify the existing warranty.
Product information on the Internet
The Operating Instructions are available on the CD-ROM shipped with the device, and on
the Internet on the Siemens homepage, where further information on the range of SITRANS
F flowmeters may also be found:
Product information on the internet (http://www.siemens.com/flow)
Worldwide contact person
If you need more information or have particular problems not covered sufficiently by the
operating instructions, please get in touch with your contact person. You can find contact
information for your local contact person on the Internet:
Local contact person (http://www.automation.siemens.com/partner)

Introduction
1.4 Further Information
Modbus RTU RS485
8 Operating Instructions, 06/2010, A5E00753974-04

Modbus RTU RS485
Operating Instructions, 06/2010, A5E00753974-04 9
2
Safety notes
CAUTION
Correct, reliable operation of the product requires proper transport, storage, positioning and
assembly as well as careful operation and maintenance. Only qualified personnel should
install or operate this instrument.
Note
Alterations to the product, including opening or improper repairs of the product, are not
permitted.
If this requirement is not observed, the CE mark and the manufacturer's warranty will expire.
2.1 Installation in hazardous area
WARNING
NOT allowed for use in hazardous areas!
Equipment used in hazardous areas must be Ex-approved and marked accordingly!
This device is NOT approved for use in hazardous areas!

Safety notes
2.1 Installation in hazardous area
Modbus RTU RS485
10 Operating Instructions, 06/2010, A5E00753974-04

Modbus RTU RS485
Operating Instructions, 06/2010, A5E00753974-04 11
3
Hardware Installation
This chapter describes the HW installation procedure for the add-on module on Siemens
Flow Instruments USM-II transmitters.
The Module can be installed into SITRANS F C MASS 6000 and SITRANS F M MAG 6000
transmitters.
Note
Not allowed for use in hazardous areas
The Communication module is NOT allowed for use in hazardous areas.
3.1 MAG/MASS 6000 IP67 or 19"
The installation of the add-on module on transmitter types SITRANS F M MAG 6000 IP67,
SITRANS F M MAG 6000 19", SITRANS F C MASS 6000 IP67 and SITRANS F C MASS
6000 19" is carried out as follows:
1. Insert the add-on module in the rear end of the transmitter
IP 67 19"

Hardware Installation
3.2 MAG 6000 I
Modbus RTU RS485
12 Operating Instructions, 06/2010, A5E00753974-04
2. Press the add-on module in the direction shown until it stops and is firmly seated in
position
3. The installation is completed
3.2 MAG 6000 I
The installation of the add-on module on a SITRANS F M MAG 6000 I is completed as
follows:
1. Open the transmitter
WARNING
Do not open the transmitter while power on

Hardware Installation
3.3 MASS 6000 Ex d
Modbus RTU RS485
Operating Instructions, 06/2010, A5E00753974-04 13
2. Press the add-on module in the direction shown until it stops and is firmly seated in
position
3. Reinsert the complete transmitter module
WARNING
Installation in hazardous area
The communication module is NOT approved for use in hazardous area.
3.3 MASS 6000 Ex d
WARNING
Installation in hazardous area
The communication module is NOT approved for use in hazardous area.
The installation of the add-on module on a SITRANS F C MASS 6000 Ex d is completed as
follows:
1. Disconnect the equipment from the supply circuits

Hardware Installation
3.3 MASS 6000 Ex d
Modbus RTU RS485
14 Operating Instructions, 06/2010, A5E00753974-04
2. Remove the rear cover by loosening the safety tap allen screw and turn the rear cover
counter-clockwise
3. Remove the electronics using the holes provided
4. Remove the flat cable from the plate
5. Remove the plate from the module bay

Hardware Installation
3.3 MASS 6000 Ex d
Modbus RTU RS485
Operating Instructions, 06/2010, A5E00753974-04 15
6. Insert the add-on module as shown.
Note
The label on the add-on module must face upwards and the connector outwards
7. Press the add-on module into position and connect the flat cable connector.

Hardware Installation
3.3 MASS 6000 Ex d
Modbus RTU RS485
16 Operating Instructions, 06/2010, A5E00753974-04

Modbus RTU RS485
Operating Instructions, 06/2010, A5E00753974-04 17
Connecting 4
On the electrical termination boards for USM-II transmitters, additional input/output terminals
have been reserved for add-on module functions. The numbering range of these terminals is
as follows, but how many are actually used depends on the type of add-on module.
Additional terminals reserved for add-on modules:
● MAG 6000: 91 - 97
● MASS 6000: 91 – 100
Note
The standard inputs and outputs continue to function and are not affected by the
presence of an add-on module. Any existing transmitter electrical connections remain
undisturbed. The MASS 6000 with extra outputs, i.e. 3 current outputs, cannot be
extended with an add-on module
WARNING
Only authorized personnel are allowed to carry to carry out work on electrical
connections.
Please refer to the relevant product operating instruction for other electrical connection
information.
Note
Shielding
Always shield a Modbus over Serial Line Cable. At one end of each cable its shield must be
connected to protective ground. If a connector is used at this end, the shell of the connector
is connected to the shield of the cable.
Note
Cable specifications
A RS485-Modbus must use a balanced pair (for D0-D1) and a third wire (for the Common).
For the balanced pairs used in an RS485-system, a Characteristic Impedance with a value
between 100 and 120 Ohms must be used.

Connecting
4.1 Wiring
Modbus RTU RS485
18 Operating Instructions, 06/2010, A5E00753974-04
4.1 Wiring
Figure 4-1 Modbus USMII connection
Table 4- 1 Connection layout
Terminal number MODBUS RTU RS485
91 T1
92 Data +
93 Data -
94 T2
PE Shield
NOTICE
Temination
Connecting 91,92 and 93,94 will add termination. This must be carried out if the device is
the last on the segment.