User Manual
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1. 0 milliseconds fixed address END Finishes configuration Stores data in non volatile memory and closes the console Rev 1 4 0 Page 17 SGW1 MB DF1 User s Manual The Embedded Modbus Slave Chapter 4 The Embedded Modbus Slave This chapter explains how to take advantage of the embedded Modbus slave Remote inputs outputs are made visible to the user through this Modbus service 4 1 Enabling the slave Refer to SLVCFG command in section 3 1 to enable the slave 4 2 Monitoring and controlling built in digital inputs and outputs Input and output pins are located in the bottom connectors of the SGW1 MB DF1 case The four digital inputs are mapped to Input Status locations as shown in the following table Pin Number 9 10 11 12 Digital Input 10 11 12 13 Input Status 10001 10002 10003 10004 Recall that Input Status locations are read only variables After you issue a read input command the pins are read and the measure is reported through the answer The four digital outputs are mapped to Coil Status locations as shown in the following table Pin Number 13 14 15 16 Digital Output 00 01 02 03 Coil Status 00001 00002 00003 00004 Coil Status locations are read write variables Thus both reads and writes are allowed for the I O pins www exemys com Rev 1 4 0 Page 18 SGW1 MB DF1 User s Manual Cabling Appendix A A Cabling A 1 Pow2. Wiring instructions 6 Figure 2 Handling incoming Modbus Requests 11 Figure 3 Power Input Connection Scheme 19 Figure 4 Digital Input connected to an external device with 20 Figure 5 Digital input connected to a dry contact 20 Figure 6 The load and the Exemys device using 21 Figure 7 The load and the Exemys device share the power supply 21 Figure 8 Connecting the computer to the SGW1 MB DF1 22 Figure 9 Connecting a Micrologix 1000 processor to the SGW1 MB DF1 22 Figure 10 Connecting an SLC 500 processor to the SGW1 MB DF1 23 Tables Table 1 Available Models 5 Table 2 Digital Inputs Technical Specifications 20 Table 3 Digital Outputs Technical Specifications 21 Table 4 Meaning of the LEDs blinking 24 Listings Listing 1 Welcome message 7 Listing 2 Modbus port configuration 7 Listing 3 DF1 port auto detection 8 Listing 4 DF1 Error detection and Modbus mode 8 Listing 5 N Files table 9 Listing 6 Insert records in the N table and B table 10 Listing 7 Contents of all the tables 10 Listing 8 Modbus related commands 12 Listing 9 DF1 related commands 13 Listing 10 Tables related commands 15 Listing 11 General commands 16 Listing 12 The list command 17 www exemys com Rev 1 4 0 Page 4 SGW1 MB DF1 User Manual Introduction Chapter 1 Introduction Thank you for your purchase SGW1 MB DF1 is a Modbus ASCII RTU to DF1 gateway SGW1 MB DF1 lets you ga
3. DF1 is configured through a serial text based console Under regular operation this console is not used Indeed it will be opened only when you start operating the device for the first time and if you eventually need to modify its configuration in the future Configured values are stored in non volatile memory so the device can be powered off without the risk of losing data Rev 1 4 0 Page 6 SGW1 MB DF1 User s Manual Getting Started 2 2 1 Opening the Serial console The serial console is physically tied to the same port used to process Modbus traffic Then you do not need to remove replace the cables every time you configure the device When SGW1 MB DF1 boots up it enables a seven seconds window to open the configuration console Within this lapse no Modbus requests will be processed However if the user opens the console it will be kept in that state until the console is explicitly closed If the seven seconds window elapses without receiving any request that opens the console the device will start working in gateway mode e g converting from Modbus ASCII RTU to DF1 To configure the device first open a terminal in your computer HyperTerminal or alike Configure the terminal to open the same RS 232 port connected to the SGW1 MB DF1 Set up the program as follows Data bits 8 Parity None Stop bit 1 Flow Control None Baud rate 9600bps Then power the device on and type CFG lt ENTER gt within the first seven seconds You
4. data such as digital inputs and statistics Holding Registers and Coils Status areas may be both read and written PLCs compatible with DF1 protocol usually map addressable data into Files and Elements A group of data with similar characteristics is called a File and each datum within a File is an Element Files are organized into File Types according to their different purposes For example N Rev 1 4 0 Page 14 SGW1 MB DF1 User s Manual Advanced Topics NOTE www exemys com Files are used to store 16 bit integers and B Files store bit variables Each File is associated to a unique File Number As mentioned in Chapter 2 SGW1 MB DF1 maintains three internal tables for the mapping between Modbus and DF1 protocol These tables are 1 Input Output 2 N Files 3 B Files and 4 S File 1 N Files This table provides the capability to map N Files which store 16 bit program variables Up to thirty two N Files will be allowed thus covering a wide range of typical situations Each Element in the File is mapped into Holding Registers allowing both reads and writes The only entry to know before inserting an N File into the table is its File Number Usually File Number 7 is associated with a default N File though other N Files could be configured using the application software provided with your PLC 2 B Files This table stores the Bit File used to keep 1 bit variables Up to two B Files can be added to the table This might seem an
5. example proposed in this chapter the Modbus master should be set as Databits 8 Baudrate 115200 Parity None Unit ID 1 Modbus mode RTU Recall that the only Modbus locations available to the master are those assigned by SGW1 MB DF1 Figure 2 illustrates how Modbus requests are handled by the device Modbus feet gt Table Look Up a7 Modbus gt DF1 Protocol Translation DF1 Request i ka DF1 Reply Modbus Master DF1 Modbus Protocol Translation Modbus Reply Figure 2 Handling incoming Modbus Requests Rev 1 4 0 Page 11 SGW1 MB DF1 User s Manual Advanced Topics Chapter 3 Advanced Topics www exemys com Chapter 2 outlined some basic configuration However for the sake of clarity many other aspects where not covered there Those topics are covered in detail in this chapter 3 1 Modbus related commands The command console includes an online help By typing neip the device sends a clear text explanation of available Modbus specific commands Listing 8 Modbus related commands gt help Help screen The following commands are available at the SGW1 MB DF1 Modbus related commands gt BBAUD n Baud Rate n 2400 4800 9600 19200 38400 57600 115200 gt BPARITY c Parity c N None E Even O Odd gt BEXCEP c Generate MB Exceptions c E Enable
6. is possible to set these parameters manually that is without detecting the values by means of the AUTODETECT command For example these fields could be filled by hand if you want to set the serial parameters before the PLC is actually connected AUTODETECT Auto detection attempts to detect the proper serial link parameters by sending iterative commands to the PLC ERROR Two methods are provided by the DF1 specification to detect frame errors BCC and CRC BCC is a one octet field appended to a DF1 frame It contains a checksum of many bytes contained in the message By the other hand the CRC which stands for Cyclic Redundancy Rev 1 4 0 Page 13 SGW1 MB DF1 User s Manual Advanced Topics www exemys com Check and is two octets long is a more robust method in the sense that it will detect more errors than BCC though it requires more computing time This setting must be coherent with that configured in the PLC if the PLC is set to BCC you have to set SGW1 MB DF1 to use BCC and vice versa SRCADDR DF1 frames define source SRC and destination DST addresses corresponding to the stations that want to exchange data While these parameters seem to be important most implementations do not take care of its values This is because DF1 is commonly used as a point to point protocol where only two stations are connected to the wire As a consequence addresses are not a matter However there are two associated protocols related to D
7. scarce resource but actually it is not Have in mind that each 1 bit location is mapped to a different Modbus Coil Status thus consuming the addressing Space very quickly Also consider that these two B Files lets you map 8192 individual bits providing an adequate space for most applications Please pay attention to command BFILEMODE when reading B Files 3 S File This is the only fixed non configurable table The mapping Input Registers 30192 30447 provides reads of internal statistics In order to work accurately I O expansion boards and other Files in general have to be configured with the application software provided by the PLC vendor Otherwise the Files will be unavailable to the SGW1 MB DF1 which will return Modbus exceptions if enabled upon unsolved requests Contact you dealer for specific information about your PLC and configuration Many newer PLCs such as FlexLogix and ControlLogix do not provide as a factory default compatibility with the type of request issued by the SGW1 MB DF1 However they incorporate a mechanism to make themselves downwards compatible with older PLCs and with the SGW1 MB DF1 Please refer to Appendix C if you are attempting to connect one of these PLCs The next help screen he1p3 command contains configuration commands specific to translation tables Listing 10 Tables related commands gt help3 Tables related commands gt TBLRST Reset all tables
8. should receive a welcome message on the terminal screen Listing 1 Welcome message SGW1 MB DF1 Exemys v1 2 gt Now the device is running in configuration mode If you cannot see a message as above check the wiring and terminal configuration 2 2 2 Serial Ports Configuration You have to configure both RS 232 ports to work with your Modbus master computer side and the DF1 device PLC side Let s configure the Modbus port first Assuming baud rate 115200 bps and no parity type the following commands Listing 2 Modbus port configuration SGW1 MB DF1 Exemys v1 2 gt mbbaud 115200 OK Baud rate 115200 gt mbparity n OK Parity NONE gt Now let s set the DF1 port An auto detection feature configures the device automatically Rev 1 4 0 Page 7 www exemys com SGW1 MB DF1 User s Manual Getting Started NOTE www exemys com Listing 3 DF1 port auto detection gt autodetect Please wait while detecting configuration Baud rate 19200 Parity NONE gt If no PLC is detected check the cable that connects SGW1 MB DF1 to the PLC and retry Next let s set the BCC CRC error detection mechanism in DF1 protocol Note that this parameter must match the one configured on the PLC Also we have to specify the Modbus mode that is ASCII or RTU Listing 4 DF1 Error detection and Modbus mode gt error cre OK Error detection mechanism CRC gt mbmode r OK ode RTU gt
9. to factory defaults gt BLVIEW F View the contents of a Translation Table gt BLDEL F P Delete one row from a Translation Table gt TBLINS F P N Insert one row into a Translation Table Parameter Legal values Rev 1 4 0 Page 15 SGW1 MB DF1 User s Manual Advanced Topics www exemys com F N B P Os REEL r0 KRZ not allowed DF1 DF1 S table N File File jis fixed Number Number Kl is the last occupied position in the N table 0 lt K1 lt 30 K2 is the last occupied position in the B table K2 0 For next help screen type HELP4 For previous help screen type HELP2 gt Note that this help screen is displayed as a chart It contains details about how to perform insertions and deletions It also shows how to view and reset the contents of the tables TBLRST This command resets the tables to factory defaults Note that the S table will remain unchanged because it is fixed not user configurable TBLVIEW This one shows the contents of a table If no parameter is appended it shows the contents of the four tables TBLDEL Deletes a record in a table TBLINS Inserts a row into a table You can insert a record into an intermediate position by selecting the appropriate row After insertion rows below the insertion point will be shifted downwards Modbus address boundaries are assigned automatically by the device For example if you insert a re
10. F1 called Data Highway DH and Data Highway DH which provide communication paths among many stations In these cases addresses are a must This field as well as the one described below provide compatibility for those protocols when interfacing the SGW1 MB DF1 with a DH DH network using a special adapter DSTADDR This command defines the destination address to be used when issuing DF1 requests You can choose to use a fixed address or copy the same address received at the Modbus side Again if running legacy DF1 this field and the one described above do not need configuration DSTCFG This parameter is closely related to the DSTADDR command It allows to use either the fixed destination address set by configuration with DSTADDR or copy the incoming Modbus address so called Unit ID BFILEMODE Some new AB PLCs organize B files in 32 bits when they talk the DF1 protocol So you can configure the converter to work with 16 bits for old PLCs or 32 bits for news PLCs 3 3 Tables related commands In this section some basic aspects on Modbus and DF1 protocols are outlined Modbus data are classified into four types These areas are known as Input Registers Holding Registers Input Status Coil Status Input Registers and Holding Registers are 16 bit words while Input Status and Coils Status refer to discrete 1 bit data By the other hand Input Registers and Input Status are read only locations used to read input
11. Modbus ASCII RTU to DF1 Converter SGW1 MB DF1 User s Manual exemys Internet Enabling Solutions www exemys com SGW1 MB DF1 User Manual Introduction ISO 9001 2000 a ANAB aK UA Exemys Products are in constant evolution to satisfy our customer needs For that reason the specifications and capabilities are subject to change without prior notice Updated information can be found at www exemys com Copyright Exemys 2006 All Rights Reserved Rev 1 4 0 www exemys com Rev 1 4 0 Page 2 SGW1 MB DF1 User Manual Introduction Index INTRODUCTION 5 GETTING STARTED 6 2 1 Wiring instructions 6 2 2 Device configuration 6 2 2 1 Opening the Serial console 7 2 2 2 Serial Ports Configuration 7 2 2 3 Configuration of the Translation Tables 8 2 3 Ready to go 11 ADVANCED TOPICS 12 3 1 Modbus related commands 12 3 2 DF1 related commands 13 3 3 Tables related commands 14 3 4 General commands 16 THE EMBEDDED MODBUS SLAVE 18 4 1 Enabling the slave 18 4 2 Monitoring and controlling built in digital inputs and outputs 18 A CABLING 19 A 1 Power 19 A 2 Ground 19 A 3 Digital Inputs 19 A 4 Digital Outputs 20 A 5 RS 232 Ports 21 A 5 1 Modbus console port 21 A 5 2 DF1 port 22 B MONITORING THE DEVICE THROUGH THE BUILT IN LEDS 24 C CONFIGURING FLEXLOGIX AND CONTROLLOGIX PLCS 25 www exemys com Rev 1 4 0 Page 3 SGW1 MB DF1 User Manual Introduction Figures Figure 1
12. Now we are done with ports configuration In the next section we will go on with the tables that tell the device how to perform the translation between both protocols 2 2 3 Configuration of the Translation Tables In order to address PLC data SGW1 MB DF1 maintains some internal Translation Tables between Modbus and DF1 protocols The tables are applied to internal Files but not to the Input Output modules connected to the PLC Many newer PLCs such as FlexLogix and ControlLogix do not provide as a factory default compatibility with the commands requested by the SGW1 MB DF1 However they include a mechanism to make themselves downwards compatible with older PLCs and with the SGW1 MB DF1 Please refer to Appendix C if you are attempting to connect one of this PLCs to the SGW1 MB DF1 Henceforth a real situation is proposed It might differ slightly from your actual configuration though we think of a study case as the best way to get in touch with your new protocol converter There is PLC that runs a program We want to make some data available to one Modbus master by means of the SGW1 MB DF1 The PLC has four Input Output boards These boards have the following I O capabilities Module Characteristics Capacity 1 16 Digital Inputs 1 word 2 32 Digital Outputs 2 words 3 4 Analog Inputs 4 words 4 32 Digital Outputs 2 words Rev 1 4 0 Page 8 SGW1 MB DF1 User s Manual Getting Started www exemys com It is required to acces
13. a dry contact Table 2 Digital Inputs Technical Specifications Digital Inputs Inputs Type Sinking Allow dry contacts and current sourcing devices Operating Voltage Range 3 5 28 Vdc Input Current 1 11 mA A 4 Digital Outputs This device provides four digital outputs located at pins 13 16 Digital outputs are Open Collector This means that when active outputs are electrically tied to GND Any load connected to an output should be powered in the range 3 45 Vdc When connecting an output to an external load two situations may occur These situations are covered below Case A The external load and the Exemys device use different power supplies See Figure 6 Case B The external load and the Exemys device share the same power supply See Figure 7 www exemys com Rev 1 4 0 Page 20 SGW1 MB DF1 User s Manual Cabling 9 30 VDC 9 26 VAC Power Supply 1234 222 se 38 2 exemys Power Power O 3 45 VDC Power Supply L10 L10 L20 L2 O LOAD Relay Lamp etc Figure 6 The load and the Exemys device using Figure 7 The load and the Exemys device share the two different power supplies power supply Table 3 Digital Outputs Technical Specifications Digital Outputs Output Type Open Collector Current Sinking Maximum Load Voltage 3 45 Vdc Max Current 130mA Max Per output A 5 RS 232 Ports This product
14. cord into the first position of the N Table the first Element is mapped to Holding Register 40192 the second Element is mapped to Holding Register 40193 and so on Thus you will have to configure your Modbus master to make polls within those boundaries in order to obtain valid answers 3 4 General commands The next help screen help4 command contains general configuration not covered in the previous screens Listing 11 General commands gt help4 General commands gt FACTRESET Restores factory defaults gt HEST Show configuration values gt HELP Display the help screen gt END Finish configuration End of help screen For previous help screen type HELP3 gt FACTRESET Resets the device to factory values recovers default configuration cleans the tables Rev 1 4 0 Page 16 SGW1 MB DF1 User s Manual www exemys com Advanced Topics LIST This command displays currently set parameters as shown below Listing 12 The list command gt list Baud rate Parity odbus exceptions ode Embedded Modbus Slave DF1 related commands Baud rate Parity essage Timeout Source address SRC Destination address DST Error detection mechanism B files bit organization gt HELP Lists the help screens Destination address option 1152 ONE 00 ENABLE RTU ENABLE D ID 240 1920 NONE 1000 0 al Use CRC 16
15. d D Disabled gt BMODE c Mode c R RTU A ASCII D Auto detection gt SGTOUT n Requests timeout Q0 lt n lt 9999 milliseconds gt SLVCFG c n Embedded Modbus Slave c E Enabled D Disabled 0 lt n lt 255 Device ID For next help screen type HELP2 gt MBBAUD this parameter sets the baud rate of the Modbus port MBPARITY configures the parity of the Modbus port MBEXCEP enables disables Modbus exceptions The term exception refers to the mechanism defined by the Modbus specification to signal error conditions such as polling to an invalid address or polling too many locations in memory Disable this feature if you do not want to receive exceptions upon a failure MBMODE selects the Modbus working mode RTU or ASCII You can also try the auto detection feature that will configure the mode when the first Modbus request arrives The format of serial data depends on which mode is configured Rev 1 4 0 Page 12 SGW1 MB DF1 User s Manual Advanced Topics www exemys com f you use Modbus ASCII serial data will be composed of one start bit seven data bits one parity bit optional if set by configuration and one stop bit f you use Modbus RTU serial data will be composed of one start bit eight data bits one parity bit optional if set by configuration and one stop bit Keep this in mind when you are to configure the Modbus master application MSGTOUT This timeout defin
16. er Figure 3 shows the power input connection which is located in the Vin terminals SGW1 MB DF1 powering has no polarity and accepts an input voltage range of 9 to 30 VDC and 9 to 26 VAC 9 30 VDC 9 26 VAC Figure 3 Power Input Connection Scheme A 2 Ground The GND pin pin number 4 is the digital ground signal used to provide grounding reference to the digital I Os and both RS 232 ports A 3 Digital Inputs Digital inputs are located at pins 9 12 They are terminated with current sinking transistors Inputs are active when a voltage in the range 3 5 28 Vdc is applied to the pins This voltage may be provided by two different ways depending on the external field device Case A Voltage is self provided by the external device that works as a current sourcing node See Figure 4 Case B Voltage is not provided by the device dry contact An external voltage must be applied See Figure 5 www exemys com Rev 1 4 0 Page 19 SGW1 MB DF1 User s Manual 9 30 VDC 9 26 VAC Power Supply Power L10 L20 Field Device PLC Sensor Encoder etc Vde COMMON Sourcing OUTPUT Voltage 3 5 a 28 VDC Max 4 Power Supply of the Device Cabling 9 30 VDC 9 26 VAC Power Supply Power L10 BO Figure 4 Digital Input connected to an external device with an independent power supply Figure 5 Digital input connected to
17. es the round trip time measured between the incoming request is received and the appropriate answer is ready to be sent back to the Modbus master If this timeout is exceeded an exception may be generated and sent back to the master if exceptions are enabled SLVCFG This parameter enables disables the embedded Modbus slave used to control and monitor the built in inputs and outputs You may disable the embedded slave if you do not need the built in I O If enabled the embedded slave receives and processes external requests issued to the configured Unit ID chapter 3 2 DF1 related commands The next help screen help2 command contains configuration commands specific to DF1 protocol Listing 9 DF1 related commands gt help2 DF1 related commands gt DF1BAUD n Baud Rate n 110 300 600 1200 2400 4800 9600 19200 38400 57600 115200 gt DF1IPARITY c Parity c N None E Even gt AUTODETECT Automatically detect baudrate and parity for DF1 link gt ERROR c Error detection mechanism c B BCC C CRC gt SRCADDR n DF1 source address 0 lt n lt 255 gt DSTADDR n DF1 destination address 0 lt n lt 255 gt DSTCFG c DF1 destination address option c F Fixed Copy Modbus address gt BFILEMODE B files organized in 16 or 32 bits 16 32 For next help screen type HELP3 For previous help screen type HELP gt DF1BAUD and DF1PARITY It
18. ilt in LEDs Appendix B B Monitoring the device through the built in LEDs The frontal LEDs provide status information about the device The meaning of the blinking is provided in the following table Table 4 Meaning of the LEDs blinking LED Meaning Green Modbus activity Yellow DF1 activity www exemys com Rev 1 4 0 Page 24 SGW1 MB DF1 User Manual Configuring FlexLogix and ControlLogix PLCs Appendix C C Configuring FlexLogix and ControlLogix PLCs Time ago Allen Bradley came out with some modifications about the way that newer PLCs exchange data In the new approach the PLC defines tags to map data rather than Files At the moment of this publication those PLCs belong to the FlexLogix and ControlLogix families The new commands are not compatible with SGW1 MB DF1 yet However AB provides downwards compatibility with the old command set SGW1 MB DF1 only uses two DF1 commands from the original DF1 command set These commands are Protected typed logical read with three address fields Protected typed logical write with three address fields Here we provide some basic information to activate the downward compatibility feature by configuring the PLC using RSLogix 5000 To map an address 7 In RSLogix 5000 software open the project file for the controller whose data you want to access 2 From the Logic menu select Map PLC SLC Messages 3 The screen shown will be used to provide the actual mapping between an a
19. in access to a wide range of industrial DF1 talking devices just by using Modbus a de facto standard in the industrial field As a bonus SGW1 MB DF1 incorporates the following features An embedded Modbus slave which provides built in digital I O for remote sensing and controlling four inputs and four outputs A serial text based console that allows full configuration of the device Table 1 Available Models Model Serial Protocols Inputs Outputs Serial Ports SGW1 2044 MB DF1 Modbus ASCIVRTU DF1 Full Duplex 4 4 2 RS 232 www exemys com Rev 1 4 0 Page 5 SGW1 MB DF1 User s Manual Getting Started Chapter 2 Getting Started www exemys com This chapter shows how to get your new SGW1 MB DF1 started It focuses on the main features of this product that is Modbus ASCII RTU to DF1 protocol conversion For clarity it is based on an example Learn how to connect the cables power up and configure the device in minutes 2 1 Wiring instructions Power supply and RS 232 ports These signals are located in the top green connectors Figure 1 shows the basic wiring Refer to Appendix A if you need more details Detach the green connectors before screwing the cables to ease the wiring Vin Power Supply Vin 0 VDC 9 26 VAC MODBUS PORT To the computer s Mee RS 232 port To TxD This is also the console port Figure 1 Wiring instructions 2 2 Device configuration SGW1 MB
20. lly one Status location The multiple coils write command only allows a write to a single coil Modules with less than one word use one complete Modbus Register Requests to Register locations up to address 64 are assumed to be requests for the modules Requests to Status locations up to address 1024 are assumed to be requests for the modules The modules will be addressed as shown in the following table according to the rules above Module Coil Status Input Status Holding Register Input Register 1 10001 10016 30001 30001 2 00001 00032 40001 40002 3 10017 10080 30002 30005 4 00033 00064 40003 40004 Rev 1 4 0 Page 9 SGW1 MB DF1 User s Manual Getting Started www exemys com For example To read output 20 in module 2 ask for Coil Status 00021 To read word 3 in module 3 ask for Input Register 30004 SGW1 MB DF1 maintains three internal tables N table lets you add and remove N Files Each element in an N File is 16 bits wide B table lets you add and remove B Files Each element in a B File is 1 bit wide S table stores the boundaries for the S File the area where many PLCs store statistics data N and B tables are user configurable but the S table is fixed The data required to insert records into the N or B table are which table to use either B or N row number File Number this number will match the one configured on the PLC Going on with the e
21. lready defined tag and the File Number you choose to make public to SGW1 MB DF1 Complete the information required as an SLC mapping Choose an appropriate File Number The tags must be controller scoped global 4 Click OK A If you want to map many data into one File you can define a tag as an array NOTE www exemys com Rev 1 4 0 Page 25
22. provides two RS 232 ports The first one is used to connect the device to the computer running Modbus ASCII RTU protocol This port is also tied to the command line console The second port provides DF1 connectivity so it is always connected to the PLC A 5 1 Modbus console port Connect your PC comport as depicted in the following figure Only TX RX and GND signals are provided do not configure any kind of flow control in the application www exemys com Rev 1 4 0 Page 21 SGW1 MB DF1 User s Manual Cabling Figure 8 Connecting the computer to the SGW1 MB DF1 A 5 2 DF1 port Connect the PLC to the DF1 port as depicted in the following figures Only TX RX and GND signals are provided do not configure any kind of flow control in the PLC Since you may connect this device to different Programmable Logic Controllers we provide two examples that illustrate the wiring diagram for this device and two commercial PLCs Micrologix 1000 Connect the Micrologix 1000 to the SGW1 MB DF1 as shown in Figure 9 8 pin Mini Din Q MLX 1000 Figure 9 Connecting a Micrologix 1000 processor to the SGW1 MB DF1 www exemys com Rev 1 4 0 Page 22 SGW1 MB DF1 User s Manual Cabling SLC 500 Connect the SLC 500 to the SGW1 MB DF1 as shown in Figure 10 Figure 10 Connecting an SLC 500 processor to the SGW1 MB DF1 www exemys com Rev 1 4 0 Page 23 SGW1 MB DF1 User s Manual Monitoring the device through the bu
23. s not only I O data but it is also important to monitor some words contained in two N Files File Numbers 7 and 10 and on some read write bit variables contained in one B File whose File Number is 3 First we may check that tables are clean at start up for example we check the N Files Table Listing 5 N Files table gt tblview n File Holding Number Register Table empty As a factory reset those tables that are configurable will be empty Input and outputs modules connected to the PLC do not require any further configuration in the SGW1 MB DF1 In order to access the modules the end user will have to issue appropriate Modbus requests thus the protocol converter will translate them into DF1 commands which can be understood by the PLC The mapping between Modbus and DF1 protocol for Input Output modules is straightforward It is summarized in the following rules Input modules can be read through Inputs Status or Input Register Output modules can be read through Coil Status or Holding Register Each Holding Register or Input Register is associated to one word 16 bits Thus each word contained in a module is assigned to one Modbus location either Holding Register or Input Register generically one Register location Each Coil Status or Input Status is associated to one bit Thus each bit contained in a module is assigned to one Modbus location either Coil Status o a Input Status generica
24. xample we insert the remaining information Listing 6 Insert records in the N table and B table gt tblins n 0 7 File N File Number 7 in record 0 N Table Record inserted gt tblins n 1 10 File N File Number 10 in record 1 N Table Record inserted gt tblins b 0 3 File B File Number 3 in record 0 B Table Record inserted Now we check all the tables by calling the t 1view command omitting any other parameter Listing 7 Contents of all the tables gt tblview N Table Length 2 File Holding Number Register 7 40192 40447 10 40448 40703 B Table Length 1 File Coil Number Status 3 01152 05247 S Table Rev 1 4 0 Page 10 SGW1 MB DF1 User s Manual Getting Started www exemys com Length 1 File Input Number Status 2 30192 30448 Note that Modbus addresses are assigned by the SGW1 MB DF1 just after inserting records into the tables This information will have to be provided to the Modbus master to poll the PLC A request that cannot be translated by the device will cause a translation error In turn SGW1 MB DF1 will report a Modbus exception if exceptions are enabled 2 3 Ready to go After filling the tables with the appropriate information the device is ready to accept polls from a Modbus master Power off and on the device wait al least seven seconds to skip the configuration mode and poll the PLC as if it had an actual Modbus port Following the
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