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ABB Motion control products 

new.abb.com/motion 
 

 

 

 

 

 

 

 

 

 

 
 
 
Modbus is an industry standard protocol that allows a 
variety of automation devices (such as Programmable 
Logic Controllers and Human Machine Interfaces) to 
communicate with each other. The Modbus protocol 
defines a simple protocol data unit (PDU) that is 
independent of the underlying communication layers.

 

Inclusion of Modbus protocol support as standard 
makes integration of ABB products with any other 
Modbus RTU/TCP device as simple as possible.

 

  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Introduction 

Controllers communicate (via RS232/422/485 Serial or Ethernet) using a Client / Server topology, in which only one device (the 

Client

) can initiate transactions (called ‘queries’). The other devices (the Servers) respond by supplying the requested data to 

the Client, or by taking the action requested in the query. Typical Client devices include host processors and programming 

panels. Typical Servers include programmable controllers. 

 

The Client can address individual Servers, or can initiate a broadcast message to all Servers. Servers return a message (called 
a ‘response’) to queries that are addressed to them individually. Responses are not returned to broadcast queries from the 
Client.  

 

The Modbus protocol establishes the format for the Client

’s query by placing into it the device (or broadcast) address, a function 

code defining the requested action, any data to be sent, and an error

–checking field. The Server’s response message is also 

constructed using the Modbus protocol. It contains fields confirming the action taken, any data to be returned, and an error

checking field. If an error occurred in receipt of the message, or if the Server is unable to perform the requested action, the 

Server will construct an error message and send it as its response. 

 

Motion Control Products 

Application note 

Integrated Modbus support

 

 

AN00198 

Rev E (EN) 

Содержание Modbus AN00198

Страница 1: ...cal Client devices include host processors and programming panels Typical Servers include programmable controllers The Client can address individual Servers or can initiate a broadcast message to all Servers Servers return a message called a response to queries that are addressed to them individually Responses are not returned to broadcast queries from the Client The Modbus protocol establishes th...

Страница 2: ... using RTU Remote Terminal Unit mode each 8 bit byte in a message contains two 4 bit hexadecimal characters Each message must be transmitted in a continuous stream The Mint interpreter offers support for Client devices with communication settings of 7 data bits 1 stop bit Even Parity 7 data bits 1 stop bit Odd Parity 8 data bits 1 stop bit No Parity Baud rates are limited to those supported by the...

Страница 3: ...ponse For a normal response the Server simply echoes the original function code For an exception response the Server returns a code that is equivalent to the original function code with its most significant bit set to a logic 1 DATA n 8 bits NUL SOH NUL SOH The data field is constructed using sets of two hexadecimal digits in the range of 00 to FF hexadecimal that are then packed into a single ASC...

Страница 4: ...mal In an exception response the Server sets the MSB of the function code to 1 This makes the function code value in an exception response exactly 80 hexadecimal higher than the value would be for a normal response With the function code s MSB set the Client s application program can recognize the exception response and can examine the data field for the exception code Data field In a normal respo...

Страница 5: ...lement 1 LSW Element 1 Element 1 LSW Element 1 3 MW0 3 Element 1 MSW Element 1 MSW 4 MW0 4 MD0 2 Element 2 LSW Element 2 Element 2 LSW Element 2 5 MW0 5 Element 2 MSW Element 2 MSW 198 MW0 198 MD0 99 Element 99 LSW Element 99 Element 99 LSW Element 99 199 MW0 199 Element 99 MSW Element 99 MSW 200 MW0 200 MD0 100 Invalid Invalid Element 100 LSW Element 100 201 MW0 201 Invalid Element 100 MSW 202 MW...

Страница 6: ...ducts Some third party Modbus products tend to use little endian word order so when using a third party Client it may be necessary to adjust this setting in the drive Modbus RTU and TCP are also supported as standard on the CP600 and CP600 eco ranges of HMI panels as well as the AC500 PLC range Network topology Modbus RTU When using 2 wire RS485 be sure to include 120 ohm terminating resistors bet...

Страница 7: ...tween the switch and the devices see Application Note AN00247 for further details Note AC500 and CP600 products use a non standard RS232 pinout so be sure to check the relevant product manual before connecting other serial devices to these products Failure to observe the correct pinout may result in damage to the connected device Supported connection types Controller The table below shows the phys...

Страница 8: ...n note Integrated Modbus support AN00198 ABB Motion control products 8 new abb com motion Example 1 Connect MotiFlex e180 Modbus TCP Client to MicroFlex e190 Modbus TCP Server via Switch or via crossover cable OR ...

Страница 9: ...Example 2 Connect MicroFlex e190 equipped with OPT SIO 1 option card Modbus RTU Server to an external PLC e g AC500 COM2 Please refer to the OPT SIO 1 Option Card of MicroFlex e190 Servo Drive Quick installation guide for more information about how to install the option card AC500 COM2 e190 OPT SIO 1 ...

Страница 10: ...lication note Integrated Modbus support AN00198 ABB Motion control products 10 new abb com motion Example 3 Connect MicroFlex e150 Modbus RTU Server to an external PLC e g AC500 eco AC500 eco COM2 e150 X6 ...

Страница 11: ...n the Workbench Toolbox to display this work area Note that for this screen to operate correctly the e190 e180 must have been Discovered via the Mint HTTP Server please refer to the MicroFlex e190 or MotiFlex e180 Installation Manual for further details about the operation of the Mint HTTP Server and the use of Discovery to automatically scan and detect these devices Click on Network to configure ...

Страница 12: ...cally add some default values as shown below These settings can be edited to suit the configuration of the connected Modbus TCP Server devices It is important to note the Server ID associated with the remote device this is automatically allocated and is one of the parameters used by the MODBUSTCPxx Mint keywords to read write data on the Server device so for example if Server ID 0 relates to 192 1...

Страница 13: ...utton at the bottom of the screen to make any changes Configuration Modbus RTU Also the Modbus RTU configuration for the MicroFlex e190 drives is performed via the Configuration screens within Mint Workbench these configuration settings can be saved as part of a controller archive to be transferred to another drive if necessary Once online to the drive click on the Configuration button in the Work...

Страница 14: ...CPFLOAT to access a single 32 bit floating point Modbus register are used Example 1 Client e180 wishes to take data from a local integer variable and write this to Netinteger 3 on a MicroFlex e190 via Modbus TCP The MicroFlex e190 has IP address 192 168 0 11 and is configured as Server ID 4 in the list of connected devices Dim nValue As Integer MODBUSTCP32 4 6 nValue Example 2 Client e180 wishes t...

Страница 15: ...234 to NETFLOAT 1 on a remote MotiFlex e180 connected via Modbus TCP The MotiFlex e180 has IP address 192 168 0 2 and is configured as Server ID 0 in the list of connected devices MODBUSTCPFLOAT 0 2 1 234 When the MicroFlex e190 or MotiFlex e180 drive is operating as a Modbus Server Netdata events will only be raised whenever the Modbus Client writes modified data to Netinteger Netfloat locations ...

Страница 16: ... motion The Client diagnostics page lets the user initiate a Read holding registers Modbus TCP function function code 03 Diagnostics about the transaction are displayed after clicking the Send button This allows the user to test basic Modbus TCP operation without the need to write any Mint code ...

Страница 17: ... RTU parameters Mint pre defined constant values for index are _mpENABLE 0 0 Disabled 1 Enabled _mpREGISTER_MAPPING 1 0 NetData array e100 default 1 Comms array ESB 2 default _mpBYTE_ORDER 2 0 Big Endian default 1 Little Endian _mpWORD_ORDER 3 0 Big Endian default 1 Little Endian _mpDROPPED_FRAMES 6 Read only counter of number of invalid packets received _mpDEBUG 7 Parameter used to display Modbus...

Страница 18: ... Protocol BBP functionality on the serial port Enabling Modbus RTU also prevents the controller from directing data from Mint PRINT statements to the serial port to avoid corruption of Modbus data packets Example Mint Code The following code snippets show typical Mint code that may be included in a NextMove controller s Startup block Example Mint code Mint Modbus RTU Server e g NextMove ESB 2 conn...

Страница 19: ...response has been generated 2 Writing a terminal channel value to ModbusParameter bus _mpDEBUG will reset diagnostic counters and setup which terminal channel is to be used to display diagnostic information Reading ModbusParameter bus _mpDEBUG will then return which terminal channel is being used for diagnostics and will display some summary information on the selected terminal channel e g last pa...

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