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Modbus Basics

 

Manual Documentation Number: Zlinx485m-1808 

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been lost. Lost communication is indicated by the Bus LED’s blinking alternately. 
The default value of 10 is usually satisfactory. The range of values is 10 to 255.  

Peer-to-Peer Slave 

To configure the Zlinx 485 Base Module for Peer-to-Peer Slave Mode: 

1.

 

Select the Configuration tab.  

2.

 

Select the Peer-to-Peer Slave option button... 

3.

 

Set the Peer-to-Peer Slave address from 1 to 255.  Please note the Peer-to-Peer Master 

address must also match. 

 

Figure 33. 

Peer-to-Peer Slave Configuration 

Input/Output Settings 

Digital inputs and analog inputs/outputs on Zlinx 485 modules are configured from the 
Input/Output tab of the Zlinx 485 Manager. The first two digital inputs on any module 
can be configured as Discrete inputs or Frequency Counter inputs. (Any additional digital 
inputs operate as Discrete inputs only.) Frequency Counter operation is only functional 
when the Zlinx 485 is set up in Modbus mode. Analog inputs and outputs can be 
configured for voltage or current loop operation. 

To configure digital and analog I/O: 

1.

 

Select the Input/Output tab. 

Summary of Contents for Zlinx 485

Page 1: ...Manual Documentation Number Zlinx485m 1808 www bb elec com www bb europe com Z Zl li in nx x 4 48 85 5 ...

Page 2: ...ectronics Ltd Westlink Commercial Park Oranmore Co Galway Ireland Phone 353 91 792444 Fax 353 91 792445 Website www bb europe com Sales e mail sales bb europe com Technical Support e mail support bb europe com Revision Original April 2008 2008 B B Electronics Mfg Co Inc No part of this publication may be reproduced or transmitted in any form or by any means electronic or mechanical including photo...

Page 3: ...rted 21 Zlinx 485 Installation 21 Computer System Requirements 21 Installing Zlinx 485 Software 21 Connecting Zlinx 485 to a PC 22 Starting Zlinx 485 Manager 22 Chapter 4 Configuration Operation 26 Configuring Zlinx 485 26 Peer to Peer Mode Settings 28 Updating Zlinx 485 Firmware 33 Chapter 5 Modbus Help 35 Modbus ASCII RTU Basics 35 Hints and Tips 36 Appendix A Product Specifications 37 Appendix ...

Page 4: ... About this Manual This manual has been created to assist you in installing configuring and using your Zlinx 485 Base module Please read it carefully and follow the instructions to achieve best results Support For additional information on this and other B B products and for technical support call 815 433 5100 option 3 or access the B B Electronics website at www bb elec com Zlinx Product Family Z...

Page 5: ...ommunications modes Small economical and configurable Tolerates a wide operating temperature range Choice of a range of DC power sources Power Data and Bus LED s Removable screw terminal blocks for power supply and I O Modbus connections Zlinx 485 Manager configuration software DIN rail mountable Package Checklist Zlinx 485 Base modules are shipped with the following items included 9 Zlinx 485 Bas...

Page 6: ... rail mountable and feature removable screw terminal blocks Zlinx 485 Modules Zlinx 485 systems consist of base modules and expansion modules Expansion modules are configured using a base module which also has programming capabilities The base module is connected to a PC that is running the Zlinx 485 Manager software Zlinx 485 systems can operate in Modbus or Peer to Peer modes In Modbus mode a Zl...

Page 7: ...xpansion Modules Up to six expansion modules can be plugged into the base module to add more I O capabilities in any combination needed For example the ZZ 8DO T Expansion module provides eight additional digital outputs the ZZ 2AI2AO provides two analog inputs and two analog outputs Refer to Appendix E for a list of Zlinx 485 models and features Expansion modules connect to base modules by pluggin...

Page 8: ...tor The base module has a programming feature that can be used to configure that base module as well as expansion modules The base module connects to the PC for configuration Connect a PC through the serial port COM1 to 16 using the provided RJ45 male to serial DB9 female cable Note A standard RJ45 to serial DB9 cable will not work use only the one supplied Figure 5 Connecting a PC and Base ...

Page 9: ...module or another base module When the LED is off no data is being transmitted or received Bus LED The Bus LED blinks green when data is being transmitted or received on the local bus connection When the LED is off no data is being transmitted or received Note If communications is not established within a preset number of retries default is 10 the Data and Bus LED s blink alternately to indicate a...

Page 10: ... receive power from the base module via the local bus connector Local Bus Connectors Local Bus connectors are included on all base and expansion modules These connectors are dual row 14 pin 2 mm spacing connectors Base modules have only a female connector Expansion modules have male connectors on one side and female connectors on the other Modules are plugged together to supply power and facilitat...

Page 11: ...ctor on the Zlinx 485 is an RJ45 female connector configured as a DCE device supporting RS 232 serial communications including TD Pin 3 on the DB9 end RD Pin 2 and GND Pin 5 signal lines If the Modbus device you are connecting to the Zlinx Base Module is configured as a DTE device you will use a straight through serial cable If the Modbus device is configured as a DCE device use a null modem cable...

Page 12: ... terminals of the Modbus device it is communicating with Its transmit terminals are connected to the receive terminals of the Modbus device it is communicating with Figure 9 RS 422 485 Four Wire Connection RS 422 485 Two Wire Mode When the Zlinx Base module is configured to operate in RS 485 two wire mode RS 422 485 switch in the right position the two wire RS 485 two wire communications cable pai...

Page 13: ...g RTS during normal operation will result in a communication failure Disable RTS if your hardware supports it Note A standard RJ45 to serial DB9 cable will not work use only the one supplied Power Supply Requirements Zlinx 485 systems can be powered from 10 to 30 VDC power sources No supply is included since the power rating of the supply will depend on the total power requirements of all modules ...

Page 14: ...8 digital inputs 8 digital outputs sourcing or sinking driver o 8 relay output model available 4 analog inputs o RTD Temperature input module available 4 analog outputs 2 analog inputs and 2 analog outputs Modules continue to be developed with additional features and options Refer to Appendix E for a list of available models and options I O Types and Characteristics Digital Inputs DI s can detect ...

Page 15: ...ignals or RTD temperature signals When configured as voltage inputs the full range is 0 to 10 VDC When configured as current inputs the full range is 0 to 20 mA and the input resistance is 240 ohms When configured as RTD input the allowable sensor types are PT100 PT1000 for CU10 Analog Outputs Analog outputs produce voltage or current output signals When configured as voltage outputs the full rang...

Page 16: ...n Module Note No external power supply wiring is required for Expansion modules DO Wiring The following diagram shows typical connection wiring for modules featuring sourcing PNP drivers Figure 13 Typical Digital Output Wiring for Sourcing Outputs ZZ 4DID0 DCT Expansion Module The following diagram shows typical connection wiring for modules featuring sinking NPN drivers ...

Page 17: ...cal Digital Output Wiring for Sinking Outputs ZZ 4DID0 DCT1 Expansion Module AI Wiring The following diagram shows typical connection wiring for analog inputs Figure 15 Typical Analog Input Wiring ZZ9D NA MR Base Module AO Wiring The following diagram shows typical connection wiring for analog outputs ...

Page 18: ...Number Zlinx485m 1808 www bb elec com www bb europe com Figure 16 Typical Analog Output Wiring ZZ9D NA MR Base Module RTD Wiring The following diagram shows typical connection wiring for RTD inputs Figure 17 Typical RTD Input Wiring ...

Page 19: ...5 base to the Modbus network To use Modbus mode successfully an understanding of the Zlinx 485 memory map assignments is necessary Modbus function codes supported Function 1 Read DO Status Function 2 Read DI s Function 3 Read AO Status Function 4 Read AI s Function 5 Write Single DO s Function 6 Write to Single AO Function 15 Write to Multiple DO s Messages sent between Zlinx 485 and a Modbus node...

Page 20: ...utput a specified voltage on AO1 the Modbus Base Module sends a message to set the register at Modbus address 40049 to the appropriate value A list of all Modbus address assignments for all Zlinx 485 points is shown in Appendix D Several important points about this list should be noted Some addresses are listed but not implemented in current versions of Zlinx 485 hardware Some addresses are reserv...

Page 21: ...Analog and digital input signals connected to AI s and DI s on one module appear on the corresponding AO s and DO s on the other module Any Expansion modules included in a Peer to Peer system must be chosen to be complimentary For example if expansion module 1 on one end of the link is a ZZ 4AI 4 analog inputs expansion module 1 on the other end of the link must be a ZZ 4AO 4 analog outputs Figure...

Page 22: ...connected Modbus device is configured as a DCE device use a null modem cable Always check the interface specifications of the Modbus device to determine whether it is a DTE or DCE before connecting RS 232 may be connected to a PC using an RS 485 Converter to allow using Modscan 32 to poll the registers For RS 422 485 wiring the Zlinx 485 Base module is connected to the Modbus device via the RS 422...

Page 23: ...Hardware Manual Documentation Number Zlinx485m 1808 www bb elec com www bb europe com Figure 24 Zlinx Base Module 2 wire RS 485 Connections Figure 25 Zlinx Base Module 4 wire RS 232 Connections ...

Page 24: ...erating systems A PC with one serial port available between COM1 and COM16 Windows XP Home or Professional with SP1 and SP2 Windows 2000 with SP4 Windows 98 SP1 Second Edition or Windows ME Installing Zlinx 485 Software To install the Zlinx 485 Manager software 1 Insert the CD included with your Zlinx 485 product into the CD ROM drive of your PC 2 The installation should launch automatically If no...

Page 25: ...he second expansion module plugs into the first etc 3 Connect the PC serial port to the Base Module using the supplied RJ45 male to serial DB9 female 6 ft cable 4 Re apply power to the Zlinx 485 Base Module The Power LED should light up Starting Zlinx 485 Manager 1 From the Windows Start menu start the Zlinx 485 Manager software The Zlinx 485 splash window appears briefly followed by the discovery...

Page 26: ...he device is not found the Progress box displays The device was not found on any serial port a Check the power supply and serial cable connections b Click the Connect button The connection process will be repeated and the device should be found 4 If Automatic connection is not desired a particular COM port 1 to 16 can be specified a Select the COM port number from the Connection drop down list b C...

Page 27: ...hints related to the current tab A graphic display of the base and expansion Modules discovered A Status bar at the bottom showing the COM port and communications parameters baud rate parity data bits stop bits and flow control An Update button used to save configuration parameters to the modules An Exit button Information Tab The Information tab displays a tree structure listing Base and expansio...

Page 28: ...dule Configuration Tab The Configuration tab contains fields that allow configuration of Communications Modes Peer to Peer Master Peer to Peer Slave Modbus and related parameters Input Output Tab The Input Output tab contains A tree structure listing input and output types for each module Input and output configuration options ...

Page 29: ...85 Zlinx 485 modules can be configured to operate as Modbus nodes or as serial links in Peer to Peer mode Configuring Modbus Mode When the Zlinx 485 receives a Modbus message to write to a discrete output 0xxxx addresses in its memory map the Zlinx 485 module turns on its corresponding digital output If a message containing holding register data is received 4xxxx addresses in its memory map the Zl...

Page 30: ... do not support broadcasts The allowable range of Modbus addresses is from 1 to 247 The default Modbus address is 1 Figure 31 Configuration Tab with Default Values Testing Modbus Mode Operation Using a Modbus base module a PC and Modbus simulation software e g Modscan you can test the link and hardware and investigate the operation of the Zlinx 485 Modscan is a Windows application that simulates a...

Page 31: ... Master address MUST match the Peer to Peer Slave address 1 255 Peer to Peer Master To configure the Zlinx 485 Base module for Peer to Peer Master mode 1 Select the Configuration tab 2 Select the Peer to Peer Master option button Figure 32 Peer to Peer Master Configuration 3 Set the Peer to Peer Master address from 1 to 255 Please note the Peer to Peer Slave address must also match 4 The Polling R...

Page 32: ...55 Please note the Peer to Peer Master address must also match Figure 33 Peer to Peer Slave Configuration Input Output Settings Digital inputs and analog inputs outputs on Zlinx 485 modules are configured from the Input Output tab of the Zlinx 485 Manager The first two digital inputs on any module can be configured as Discrete inputs or Frequency Counter inputs Any additional digital inputs operat...

Page 33: ...igured 3 Select Discrete or Frequency Counter for the first two inputs only Do NOT exceed 5 kHz for frequency input Setting the Digital Mode of either of the first two DI s to Frequency Mode sets both DI s on that module to the same mode Do NOT exceed 5 kHz for frequency input 4 Select the Analog Input to be configured 5 Select the required Analog Mode 0 to 10 VDC or 0 to 20 mA Setting the Analog ...

Page 34: ...linx485m 1808 www bb elec com www bb europe com Figure 35 Analog Input Configuration 6 Select the Analog Output to be configured 7 Select the required Analog Mode 0 to 10 VDC or 0 to 20 mA If RTD module present then 1 Select the Input Output tab ...

Page 35: ...ck the Channel Enabled option 4 Select the RTD type as PT100 PT1000 CU10 depending on your RTD type 5 Select if you have wired a 2 3 or 4 wire RTD probe to the input module Setting the Analog Mode of one AI or AO sets all AI s and AO s on that module to the same mode Saving the Configuration When all configuration settings are complete click the Update button to save them in the Zlinx 485 Base and...

Page 36: ...ing procedure describes the firmware updating process 4 Disconnect power from the base module 5 Disconnect all modules from external equipment The easiest way to disconnect is to unplug all terminal blocks 6 Connect expansion modules requiring updates to the base module The male local bus connector on the first expansion module plugs into the female connector on the base module The second expansio...

Page 37: ...he base or expansion module to be updated 15 In the Firmware Image drop down box select the image file hex 16 Click the Program button to load the firmware into the module 17 When all updates are complete click Exit 18 Before reconnecting the I O run the Zlinx 485 Manager software and check to ensure all modules are configured properly 19 When the configuration check is complete a Exit the Zlinx 4...

Page 38: ... RTU All Modbus communications are initiated by Modbus masters using a polling query response format The master can send broadcast messages using a slave address of 0 which all slaves accept but do not reply to More commonly the master polls individual slaves sequentially In each poll it sends a message containing a device address followed by a function code any data that maybe required and an err...

Page 39: ...n misperception is that every serial network must terminate with a resistor While this was true of early serial network configurations it s typically the wrong answer call our technical support and verify if you re an exception at 815 433 5100 option 3 A sometimes difficult problem is difference in grounding voltage between various network locations Stray voltage from lightning or other sources ma...

Page 40: ...m Expansion Feature 1 base module and up to 6 expansion modules Power Indicator Red LED Data Indicator Green LED blinks with TD or RD data traffic Off no data traffic Bus Indicator Green LED blinks with TD or RD bus traffic Off no bus traffic Data Error Indicator Data Bus LED s blink alternately Modbus Connectors Removable screw terminal 5 position block 3 5 mm spacing Serial Connectors Side conne...

Page 41: ...tput AO Max Source Load 375 ohms at 20 mA and 10V input voltage when configured for current output Input Protection Over voltage to 2x max input voltage Power Supply Voltage Requirements 10 VDC to 30 VDC Power Supply Not included Base Module Power Connector Removable screw terminal 2 block 3 5 mm spacing Relay Outputs Number of Relays 8 Type C normally open and normally closed Output Connection 3 ...

Page 42: ...D1 0 4W Operating Temperature 40 to 80 C 40 to 176 F ZZ 8DO R 40 to 65ºC 40 to 149 º F Storage Temperature 40 to 85 C 40 to 185 F Humidity 10 to 90 R H non condensing Enclosure Rating IP30 Mounting DIN rail mount 35 mm Certifications FCC Part 15 Class A CISPR EN55022 Class A EN61000 6 1 Generic Standards for Residential Commercial Light Industrial EN61000 4 2 ESD EN61000 4 3 RFI EN61000 4 4 EFT EN...

Page 43: ... Manual Documentation Number Zlinx485m 1808 www bb elec com www bb europe com A Ap pp pe en nd di ix x B B D Di im me en ns si io on na al l D Di ia ag gr ra am ms s Figure 37 Dimensional Diagram of a Zlinx 485 Base Module ...

Page 44: ...CE 1 Signal Ground GND 2 Signal Ground GND 3 Receive Data RD IN 4 Transmit Data TD OUT 5 Clear to Send CTS IN 6 Request to Send RTS OUT 7 Not Used 8 Not used Figure 38 RS 232 Connections for RJ45 type plug Note PIN 4 RTS is reserved for the configuration software only Asserting RTS during normal operation will result in a communication failure Disable RTS if your hardware supports it RJ45 Male to ...

Page 45: ...ve Data RDA In 3 Receive Data RDB In 4 Signal Ground COM COM 5 Figure 40 Zlinx Base Module Terminal Block Pin out for RS 422 485 Four Wire Operation Note 4 Wire Connections must be wired as Mater Slave Refer to B B Electronics RS 485 Application Note RS 485 2 Wire Pinouts RJ45 male DB9 female Signal Name Direction 1 5 Signal Ground 2 5 Signal Ground 3 3 Receive Data IN 4 2 Transmit Data OUT 5 7 Cl...

Page 46: ...5m 1808 www bb elec com www bb europe com Figure 41 Zlinx 485 Base Module Terminal Block Pin out for RS 485 Two Wire Operation Signal Name Label Direction Terminal DataA TDA In Out 1 DataB TDB In Out 2 Not used RDA 3 Not used RDB 4 Signal Ground COM COM 5 ...

Page 47: ... Output 12 0 1 Refer to Appendix A 00013 Base Digital Output 13 0 1 Refer to Appendix A 00014 Base Digital Output 14 0 1 Refer to Appendix A 00015 Base Digital Output 15 0 1 Refer to Appendix A 00016 Base Digital Output 16 0 1 Refer to Appendix A 00017 EXP 1 Digital Output 1 0 1 Refer to Appendix A 00018 EXP 1 Digital Output 2 0 1 Refer to Appendix A 00019 EXP 1 Digital Output 3 0 1 Refer to Appen...

Page 48: ...gital Output 10 0 1 Refer to Appendix A 00059 EXP 3 Digital Output 11 0 1 Refer to Appendix A 00060 EXP 3 Digital Output 12 0 1 Refer to Appendix A 00061 EXP 3 Digital Output 13 0 1 Refer to Appendix A 00062 EXP 3 Digital Output 14 0 1 Refer to Appendix A 00063 EXP 3 Digital Output 15 0 1 Refer to Appendix A 00064 EXP 3 Digital Output 16 0 1 Refer to Appendix A 00065 EXP 4 Digital Output 1 0 1 Ref...

Page 49: ...igital Output 16 1 0 1 Refer to Appendix A 00097 EXP 6 Digital Output 1 0 1 Refer to Appendix A 00098 EXP 6 Digital Output 2 0 1 Refer to Appendix A 00099 EXP 6 Digital Output 3 0 1 Refer to Appendix A 00100 EXP 6 Digital Output 4 0 1 Refer to Appendix A 00101 EXP 6 Digital Output 5 0 1 Refer to Appendix A 00102 EXP 6 Digital Output 6 0 1 Refer to Appendix A 00103 EXP 6 Digital Output 7 0 1 Refer ...

Page 50: ...DO 2AI 2AO sinking DO s ZZ ND 485 Base Modbus Digital I O Analog I O RS 422 485 RS 232 4DI 4DO sinking DO s Expansion Modules Model Number Type I O I O Types ZZ 4AI Analog Input Module 4AI mA V ZZ 4AO Analog Output Module 4AO mA V ZZ 2AI2AO Analog Input Output Module 2AI 2AO mA V ZZ 8DI DC Digital Input Module 8DI Pull up R ZZ 8DO T Digital Output Module 8DO sourcing ZZ 8DO T1 Digital Output Modul...

Page 51: ...firmware with the Firmware Updater Program No Peer Peer communication link The serial connection is not established Verify that all parameters in the configuration tab in the programming software are correct Too many expansion modules installed Only 6 expansion modules may be connected to any base module Expansion modules in peer peer mode do not match In peer peer mode the master and slave must h...

Page 52: ...e com A Ap pp pe en nd di ix x G G T Te er rm ms s a an nd d D De ef fi in ni it ti io on ns s Term Definition Base module Master node with I O Expansion module Expansion node that responds to master node Local bus header plug B B proprietary RS 485 bus interconnection via 14 pin 2 mm connector ...

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