SMC Sierra Monitor FieldServer Driver Manual
Driver Revision: 1.12
Document Revision: 4.B
APPLICABILITY & EFFECTIVITY
Effective for all systems manufactured after October 2016.
FieldServer
FS-8704-03 Modbus TCP/IP
Driver Manual
(Supplement to the FieldServer Instruction Manual)
Modbus TCP/IP Driver Manual
Technical Support
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Website: www.sierramonitor.com
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Contact Information
Modbus TCP/IP Driver Manual
TABLE OF CONTENTS
1 Modbus TCP/IP Description ................................................................................................................ 4
2 Driver Scope of Supply ....................................................................................................................... 4
2.1 Supplied by Sierra Monitor for this driver ............................................................................ 4
2.2 Provided by the Supplier of 3rd Party Equipment ............................................................... 4
2.2.1 Hardware ............................................................................................................................... 4
3 Hardware Connections ........................................................................................................................ 5
4 Data Array Parameters ........................................................................................................................ 6
5 Configuring the FieldServer as a Modbus TCP/IP Client ................................................................. 7
5.1 Client Side Connection Parameters ............................................................................................... 7
5.2 Client Side Node Parameters ......................................................................................................... 8
5.3 Client Side Map Descriptor Parameters ......................................................................................... 9
5.3.1 FieldServer Specific Map Descriptor Parameters ................................................................... 9
5.3.2 Driver Specific Map Descriptor Parameters ............................................................................ 9
5.3.3 Timing Parameters ................................................................................................................ 10
5.3.4 Map Descriptor Examples ..................................................................................................... 11
6 Configuring the FieldServer as a Modbus TCP/IP Server ............................................................. 12
6.1 Server Side Connection Parameters ............................................................................................ 12
6.2 Server Side Node Parameters ...................................................................................................... 13
6.3 Server Side Map Descriptor Parameters ...................................................................................... 14
6.3.1 FieldServer Specific Map Descriptor Parameters ................................................................. 14
6.3.2 Driver Specific Map Descriptor Parameters .......................................................................... 14
6.3.3 Map Descriptor Examples ..................................................................................................... 15
6.3.4 Slave_ID ................................................................................................................................ 15
6.3.4.1 Slave_ID Lookup in Table .............................................................................................. 15
Appendix A. Useful Features ................................................................................................................... 16
Appendix A.1. Managing Floating Points with Modbus ........................................................................... 16
Appendix A.1.1. Transferring Non-integer Values with One Register ................................. 16
Appendix A.1.2. Transferring Float/32 bit Values with Two Registers................................ 16
Appendix A.2. Node_Offline_Response .................................................................................................. 17
Appendix A.3. Splitting Registers into Bytes or Bits ................................................................................ 18
Appendix A.4. Reading Device Identification .......................................................................................... 18
Appendix A.4.1. Client Side Map Descriptor ............................................................................. 18
Appendix A.4.2. Server Side Map Descriptor ............................................................................ 19
Appendix A.5. Broadcasting Write Messages ......................................................................................... 19
Appendix A.6. Reading Scattered Addresses ......................................................................................... 20
Appendix B. Troubleshooting .................................................................................................................. 21
Appendix B.1. Server Configuration of System Station Address ............................................................ 21
Appendix B.2. Modbus TCP/IP Connection Error Descriptions .............................................................. 21
Appendix B.3. Understanding Max Concurrent Messages ..................................................................... 21
Appendix C. Reference ............................................................................................................................. 23
Appendix C.1. Data Types ...................................................................................................................... 23
Appendix C.2. Single Writes .................................................................................................................... 23
Appendix C.3. Driver Error Messages ..................................................................................................... 23
Table of Contents
Modbus TCP/IP Driver Manual
PART #
Description
FS-8915-10
UTP cable (7 foot) for Ethernet connection1
Description
Modbus/TCP Server, e.g. Quantum PLC
2
Modbus/TCP Host Node [such as: Intellution Fix, Wondereware Intouch, GE Cimplicity, Quantum PLC
(Master)]
3
1
2
3
1 MODBUS TCP/IP DESCRIPTION
The Modbus TCP Driver allows the FieldServer to transfer data to and from devices over Ethernet using
the Modbus TCP/IP Protocol. The Modbus TCP/IP driver uses port 502, which is not configurable. The
driver was developed for Modbus Application Protocol Specification V1.1a from Modbus-IDA. The
specification can be found at www.modbus.org. The FieldServer can emulate either a Server or Client.
The information that follows describes how to expand upon the factory defaults provided in the
configuration files included with the FieldServer.
There are various register mapping models being followed by various vendors.
To cover all these mappings, FieldServer uses the following three Models:
Modicon_5digit – Use this format where addresses are defined in 0xxxx, 1xxxx, 3xxxx or 4xxxx
format. A maximum of 9999 registers can be mapped of each type. This is FieldServer driver’s
default format.
ADU – Application Data Unit address. Use this format where addresses of each type are defined
in the range 1-65536.
PDU – Protocol Data unit address. Use this format where addresses of each type are defined in
the range 0-65535.
An example of the key difference between ADU and PDU:
If Address_Type is ADU and address is 1, the driver will poll for register 0.
If Address_Type is PDU, the driver will poll for address 1.
NOTE: If the vendor document shows addresses in extended Modicon (i.e. 6 digit) format like
4xxxxx then consider these addresses as xxxxx (omit the first digit) and use either ADU or
PDU.
NOTE: The purpose of providing 3 different ways of addressing the Modbus registers is to allow
the user to choose the addressing system most compatible with the address list being
used. At the protocol level, the same protocol specification is used for all three with the
exception of the limited address range for Modicon_5digit.
2 DRIVER SCOPE OF SUPPLY
2.1 Supplied by Sierra Monitor for this driver
2.2 Provided by the Supplier of 3rd Party Equipment
2.2.1 Hardware
This cable is necessary for connection to the driver. It is shipped with the FieldServer and not separately with the driver.
If FieldServer is used as a Modbus/TCP Client.
If FieldServer is used as a Modbus/TCP Server.
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Modbus TCP/IP Driver Manual
FieldServer
FieldServer Part #
8915-10
UTP cable
Connect to an Ethernet Port
on the FieldServer
N1
18
Switch
Remote Modbus
Device
3 HARDWARE CONNECTIONS
Configure the PLC according to manufacturer’s instructions.
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Modbus TCP/IP Driver Manual
Section Title
Data_Arrays
Column Title
Function
Legal Values
Data_Array_Name
Provide name for Data Array.
Up to 15 alphanumeric
characters
Data_Array_Format
Provide data format. Each Data Array can only
take on one format.
UINT 16, UINT 32, SINT 16,
SINT 32, BIT, FLOAT
Data_Array_Length
Number of Data Objects. Must be larger than the
data storage area required by the Map Descriptors
for the data being placed in this array.
1 – 255
// Data Arrays
Data_Arrays
Data_Array_Name
, Data_Array_Format
, Data_Array_Length
DA_AI_01
, Float
, 200
DA_AO_01
, Float
, 200
DA_DI_01
, Bit
, 200
DA_DO_01
, Bit
, 200
4 DATA ARRAY PARAMETERS
Data Arrays are “protocol neutral” data buffers for storage of data to be passed between protocols. It is
necessary to declare the data format of each of the Data Arrays to facilitate correct storage of the relevant
data.
Example
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Modbus TCP/IP Driver Manual
Section Title
Connections
Column Title
Function
Legal Values
Adapter
Specify which adapter this protocol uses.
N1
Protocol
Specify protocol used.
Modbus/TCP
Poll Delay*
Time interval between polls.
0-32000 s, 0.05 s
Max_Concurrent_Messages*4
Specify the maximum messages the driver
can send, before waiting for responses.
0 – 65534
(0 or 1 disables
concurrent messaging
meaning only 1 active
message at a time)
// Client Side Connections
Connections
Adapter
, Protocol
, Poll_Delay
N1
, Modbus/TCP
, 0.05s
4
5 CONFIGURING THE FIELDSERVER AS A MODBUS TCP/IP CLIENT
For detailed information on FieldServer configuration, refer to the FieldServer Configuration Manual. The
information that follows describes how to expand upon the factory defaults provided in the configuration
files included with the FieldServer (see “.csv” sample files provided with the FieldServer).
This section documents and describes the parameters necessary for configuring the FieldServer to
communicate with a Modbus TCP/IP Server.
The configuration file tells the FieldServer about its interfaces, and the routing of data required. In order to
enable the FieldServer for Modbus TCP/IP communications the following three actions must be taken.
The driver independent FieldServer buffers need to be declared in the “Data Arrays” section. The
destination device addresses need to be declared in the “Client Side Nodes” section. And the data
required from the server(s) needs to be mapped in the “Client Side Map Descriptors” section. Details on
how to perform these steps can be found in the following sections.
NOTE: In the following tables, * indicates an optional parameter with the bold legal value as the default.
5.1 Client Side Connection Parameters
Example
Using Max_Concurrent_Messages value > 1 could improve communication performance, but it also depends on the remote
Server’s implementation. The server might not support multiple messaging, so match this number with the Server's capability.
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