Teledyne 2103c installation and operation guide Establishing

Page 28

2103 Modem Module

 

 

Section 4

Modbus Protocol

 

 

 

 

 

 

 

 

By accessing these registers you can obtain the current value of

 

 

whatever parameter you desire. The reading(s) can then be dis-

 

 

played or stored wherever you designate as a destination; for

 

 

example, a process control computer.

 

 

 

 

 

 

Note

 

 

 

Level, flow, velocity, and temperature data is stored in metric

 

 

 

units only.

 

 

Not all registers are limited to read-only data storage. You can

 

 

also use some registers for control purposes. For example, by

 

 

writing a “1” value to register 24 (“Identify Module” register), you

 

 

will tell a 2100 module to light the LED on the front of the

 

 

module.

4.2.1

Establishing

There are several different communications protocols supported

 

Communication

in the 2100 series that require auto-baud rate detection. Because

 

 

of this, each time a modbus connection is made, the module uses

 

 

a polling mechanism to repeatedly send a command until a

response is received. It may take up to 20 command retries before the module has identified the baud rate and a response is received.

4.2.2Module Addressing When connecting to a site via a Modbus OPC server, you use a dedicated line of communication to that module or stack from the OPC server, which can be a dedicated communications cable (direct connection) or a dedicated phone number (modem).

When you are using a direct connection, you are dedicating a specified COM port on the computer, and that COM port deter- mines the site to which you are connecting.

When you are using a modem, the dedicated line is defined by the site's phone number.

If you connect more than one 2100 Series module at a site, the Modbus OPC server, while using the shared communication line for all of the modules within the network, must have some way to differentiate between the modules. When sending a command to a specific module, the command has an address field. This allows the server software to talk to, as well as control, the specified module, while ignoring other modules in the same stack or site.

Each module capable of Modbus Protocol communication will automatically create its own specific ASCII address within the site, using:

•The model numbers of the modules

•The user-defined module names

4-2

Page 27 Page 29
Image 28
Page 27 Page 29
Contents 2103/2103c Modem Module Page Foreword Page Table of Contents Modem ModuleAppendix a Replacement Parts Appendix B AccessoriesAppendix C Material Safety Data Sheets List of FiguresIntroduction Introduction Product DescriptionIdentifying Module Components 2103 Modem Module Components Top View2103 Modem Module Components Bottom View 2103 Modem Module Technical Specifications 2103 Communication Connector Pins Only Safety Symbols and Hazard Alerts 2103 Modem Cable ConnectorTechnical Service Modem Module Introduction Safety Installation and OperationUnpacking Instructions Installation Modem Module Installation and OperationTelephone Line Connection 2103 only 2103 Modem is in compliance with FCC part 68 rules. HoweverService is subject to state tariffs Modem Cable Connecting to Flowlink Flowlink Connect ScreenPushed Data Capability Modem Module Installation and Operation Overview 2103c Cellular Modem ModuleAntenna Options Programming Modem Module 2103c Cellular Modem ModuleSetting dialout phone numbers and alarm conditions TAP Service Parameters Modbus Protocol OperationEstablishing Configurations Configuration Example Direct Connection ShownGlossary of Terms Common Acronyms Modbus Ascii Address 1 Register Definitions Modbus Ascii Address 2-N+1 Register Definitions 117 Volume 1 status code Bit integer Read Measurement Parameters by Model Number Modem Module Modbus Protocol Maintenance Overview MaintenanceMaintenance Kit Desiccant DesiccantHydrophobic Filter Rings Modem Module Maintenance Appendix a Replacement Parts Replacement Parts1 2103 Replacement Parts Modem Module Appendix a Replacement Parts Modem Module Appendix a Replacement Parts 2 2103c Replacement Parts Modem Module Appendix a Replacement Parts Modem Module Appendix a Replacement Parts Modem Module Appendix a Replacement Parts Modem Module Appendix a Replacement Parts Modem Module Appendix a Replacement Parts Modem Module Appendix a Replacement Parts Modem Module Appendix a Replacement Parts Appendix B Accessories How to Order General AccessoriesModem Module Appendix B Accessories Appendix C Material Safety Data Sheets Material Safety Data Sheet Health Hazard Data Material Safety Data Sheet First Aid Measures Exposure Controls/Personal Protection Toxicological Information Other Information Declaration of Conformity Page Control and Laboratory use Page Teledyne Isco One Year Limited Factory Service Warranty
Top Page Image Contents