Difference between revisions of "Component: Modbus Slave (Comms: System)"

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|-
 
|-
 
| width="20%" style="color: gray;" | Version
 
| width="20%" style="color: gray;" | Version
−
| 1.2 (Release)
+
| 1.3 (Release)
 
|-
 
|-
 
| width="20%" style="color: gray;" | Category
 
| width="20%" style="color: gray;" | Category
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==Examples==
 
==Examples==
−
 
  
 
Example master program to control the slave. The example reads the 8 switches connected to PortD. If the switch values change then the new value is send to the slave.
 
Example master program to control the slave. The example reads the 8 switches connected to PortD. If the switch values change then the new value is send to the slave.
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{{Fcfile|ModBus_Slave_Example1.fcfx|Modbus Slave Example}}
 
{{Fcfile|ModBus_Slave_Example1.fcfx|Modbus Slave Example}}
  
 +
 +
===Addressing===
 +
 +
In Modbus the addressing protocol looks like this.
 +
 +
{| width="80%"
 +
|'''Data Type'''
 +
|'''Common name'''
 +
|'''Starting address'''
 +
|'''Ending Address'''
 +
|'''Flowcode Start Address'''
 +
|'''Flowcode End Address'''
 +
|-
 +
|Modbus Coils
 +
|Bits, binary values, flags
 +
|00001
 +
|10000
 +
|0
 +
|9999
 +
|-
 +
|Digital Inputs
 +
|Binary inputs
 +
|10001
 +
|30000
 +
|0
 +
|19999
 +
|-
 +
|Analog Inputs
 +
|Binary inputs
 +
|30001
 +
|40000
 +
|0
 +
|9999
 +
|-
 +
|Modbus Registers
 +
|Analog values, variables
 +
|40001
 +
|60000
 +
|0
 +
|19999
 +
|}
 +
 +
 +
In Flowcode each section starts from 0 so the address range is as shown.
  
  
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 +
 +
<span style="font-weight: normal;"><u>Reply Delay</u></span>
 +
 +
This property is of type ''Unsigned integer'' and can be referenced with the variable name ''ReplyDelay''.
 +
 +
Delay in micro seconds to wait before transmitting a reply
  
 
<span style="font-weight: normal;"><u>Label</u></span>
 
<span style="font-weight: normal;"><u>Label</u></span>
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This property is of type ''Unsigned integer'' and can be referenced with the variable name ''StartAdrCoil''.
 
This property is of type ''Unsigned integer'' and can be referenced with the variable name ''StartAdrCoil''.
  
−
''<span style="color:red;">No additional information</span>''
+
Start address of the Modbus coils. Referenced from 0.
 +
 
 +
For example
  
 +
Slave 1 might have 100 coils addressed 0-99 Start Address = 0
  
 +
Slave 2 might have 100 coils addressed 100-199 Start Address = 100
  
 
<span style="font-weight: normal;"><u>Number of Addresses</u></span>
 
<span style="font-weight: normal;"><u>Number of Addresses</u></span>
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This property is of type ''Unsigned integer'' and can be referenced with the variable name ''NumAdrCoil''.
 
This property is of type ''Unsigned integer'' and can be referenced with the variable name ''NumAdrCoil''.
  
−
Specifies how many Coils are available on the slave. Max 80 coils.
+
Specifies how many Coils are available on the slave.
 +
 
 +
Each address consumes a single bit of RAM, 8 Addresses are packed together into a single RAM Byte.
  
 
<span style="font-weight: normal;"><u>Starting Address</u></span>
 
<span style="font-weight: normal;"><u>Starting Address</u></span>
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This property is of type ''Unsigned integer'' and can be referenced with the variable name ''StartAdrDI''.
 
This property is of type ''Unsigned integer'' and can be referenced with the variable name ''StartAdrDI''.
  
−
''<span style="color:red;">No additional information</span>''
+
Start address of the Modbus digital inputs. Referenced from 0.
 +
 
 +
For example
  
 +
Slave 1 might have 100 inputs addressed 0-99 Start Address = 0
  
 +
Slave 2 might have 100 inputs addressed 100-199 Start Address = 100
  
 
<span style="font-weight: normal;"><u>Number of Addresses</u></span>
 
<span style="font-weight: normal;"><u>Number of Addresses</u></span>
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This property is of type ''Unsigned integer'' and can be referenced with the variable name ''NumAdrDI''.
 
This property is of type ''Unsigned integer'' and can be referenced with the variable name ''NumAdrDI''.
  
−
Specifies how many Digital Inputs are available on the slave. Max 80.
+
Specifies how many Digital Inputs are available on the slave.
 +
 
 +
Each address consumes a single bit of RAM, 8 Addresses are packed together into a single RAM Byte.
  
 
<span style="font-weight: normal;"><u>Starting Address</u></span>
 
<span style="font-weight: normal;"><u>Starting Address</u></span>
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This property is of type ''Unsigned integer'' and can be referenced with the variable name ''StartAdrAI''.
 
This property is of type ''Unsigned integer'' and can be referenced with the variable name ''StartAdrAI''.
  
−
''<span style="color:red;">No additional information</span>''
+
Start address of the Modbus analogue inputs. Referenced from 0.
 +
 
 +
For example
  
 +
Slave 1 might have 100 inputs addressed 0-99 Start Address = 0
  
 +
Slave 2 might have 100 inputs addressed 100-199 Start Address = 100
  
 
<span style="font-weight: normal;"><u>Number of Addresses</u></span>
 
<span style="font-weight: normal;"><u>Number of Addresses</u></span>
Line 366: Line 431:
 
This property is of type ''Unsigned integer'' and can be referenced with the variable name ''NumAdrAI''.
 
This property is of type ''Unsigned integer'' and can be referenced with the variable name ''NumAdrAI''.
  
−
Specifies how many 16-bit analogue inputs are available on the slave. Max 10.
+
Specifies how many 16-bit analogue inputs are available on the slave.
 +
 
 +
Each address consumes two RAM Bytes.
  
 
<span style="font-weight: normal;"><u>Starting Address</u></span>
 
<span style="font-weight: normal;"><u>Starting Address</u></span>
Line 372: Line 439:
 
This property is of type ''Unsigned integer'' and can be referenced with the variable name ''StartAdrReg''.
 
This property is of type ''Unsigned integer'' and can be referenced with the variable name ''StartAdrReg''.
  
−
''<span style="color:red;">No additional information</span>''
+
Start address of the Modbus registers. Referenced from 0.
 +
 
 +
For example
  
 +
Slave 1 might have 100 registers addressed 0-99 Start Address = 0
  
 +
Slave 2 might have 100 registers addressed 100-199 Start Address = 100
  
 
<span style="font-weight: normal;"><u>Number of Addresses</u></span>
 
<span style="font-weight: normal;"><u>Number of Addresses</u></span>
Line 380: Line 451:
 
This property is of type ''Unsigned integer'' and can be referenced with the variable name ''NumAdrReg''.
 
This property is of type ''Unsigned integer'' and can be referenced with the variable name ''NumAdrReg''.
  
−
''<span style="color:red;">No additional information</span>''
+
Specifies how many 16-bit holding registers are available on the slave.
 +
 
 +
Each address consumes two RAM Bytes.

Latest revision as of 10:07, 21 March 2017


Author Matrix Ltd.
Version 1.3 (Release)
Category Comms: System


Image Modbus Slave component

Modbus component for creating Modbus compatible slave hardware via RS232 or RS485.

Examples

Example master program to control the slave. The example reads the 8 switches connected to PortD. If the switch values change then the new value is send to the slave.

FC6 Icon.png Modbus Master Example


Example slave program to react to the signals from the master. The example listens for Modbus commands from the master and outputs the current coils 0-7 state to eight LEDs connected to PortD.

FC6 Icon.png Modbus Slave Example


Addressing

In Modbus the addressing protocol looks like this.

Data Type Common name Starting address Ending Address Flowcode Start Address Flowcode End Address
Modbus Coils Bits, binary values, flags 00001 10000 0 9999
Digital Inputs Binary inputs 10001 30000 0 19999
Analog Inputs Binary inputs 30001 40000 0 9999
Modbus Registers Analog values, variables 40001 60000 0 19999


In Flowcode each section starts from 0 so the address range is as shown.


Downloadable macro reference

ReadHoldingRegister

Reads the value of a single holding register.

Parameters

UINT Address
Coil Address


Return value

UINT


ReadCoilStates

Reads the state of a single digital coil.

Can pack a max of 8-bits together in a single operation

Parameters

UINT StartAddress
Coil Address Range 0 to (NumCoils - 1)
BYTE AddressCount
Range 1-8


Return value

BYTE


ReadAnalogueInput

Reads the value of a single analogue input.

Parameters

UINT Address
Coil Address


Return value

UINT


ReadInputStates

Reads the state of a single digital input.

Can pack a max of 8-bits together in a single operation

Parameters

UINT StartAddress
Coil Address Range 0 to (NumCoils - 1)
BYTE AddressCount
Range 1-8


Return value

BYTE


SetSlaveAddress

Allows the slave address to be overridden from the default slave address specified

in the component property. The number of bytes used for the address is fixed by the

Slave ID Bytes property to save on RAM usage.

Parameters

UINT SlaveAddress


Return value

This call does not return a value


SetCoilState

Sets the state of a single digital coil.

Parameters

UINT Address
Coil Address
BYTE State
0=off, 1=on


Return value

This call does not return a value


SetInputState

Sets the state of a single digital input.

Parameters

UINT Address
Coil Address
BYTE State
0=off, 1=on


Return value

This call does not return a value


SetBaudRate

Allows the Baud Rate to be controlled dynamically overriding the default

rate specified by the Baud component property.

Parameters

BYTE Rate
0=1200, 1=2400, 2=4800, 3=9600, 4=19200, 5=38400, 6=57600, 7=115200


Return value

This call does not return a value


SetHoldingRegister

Sets the state of a single holding register.

Parameters

UINT Address
Coil Address
UINT Value
Analogue Value range 0 - 65535


Return value

This call does not return a value


CheckForIncoming

Checks for an incoming message and if the data address is within range then also automatically replies with the correct reply.

Returns 0 if no comms received, 1 for a succesful transaction, 255 for an error.

Parameters

This macro has no parameters


Return value

BYTE


SetAnalogueInput

Sets the state of a single analogue input.

Parameters

UINT Address
Coil Address
UINT Value
Analogue Value range 0 - 65535


Return value

This call does not return a value


Initialise

Starts up the UART to allow communications and initialises the states of the various

Modbus Coils, Inputs and Registers to 0.

Parameters

This macro has no parameters


Return value

This call does not return a value


Simulation macro reference

This component does not contain any simulation macros


Property reference

Channel

This property is of type Fixed list of ints and can be referenced with the variable name CHANNEL.

UART channel to specify an onboard hardware channel.

Software channels are not availlable as we rely on hardware UART RX interrupts to pull in the data

TX

This property is of type Single digital pin and can be referenced with the variable name TX.

UART transmit pin

RX

This property is of type Single digital pin and can be referenced with the variable name RX.

UART receive pin

Baud Rate

This property is of type Fixed list of ints and can be referenced with the variable name BAUD_LIST.

Data rate in bits per second

Bus

This property is of type Fixed list of ints and can be referenced with the variable name BusType.

Specifies the bus mode being used,

RS232 allows you to connect a single master node to a single slave node.

RS485 allows you to connect a single master node to multiple slave nodes.

Timeout

This property is of type Unsigned integer and can be referenced with the variable name Timeout.

Timeout in milliseconds used to dictate the maximum time to wait in milliseconds between bytes in a packet.

Range: 1 - 255

Frame Type

This property is of type Fixed list of ints and can be referenced with the variable name FrameType.

Switches between RTU and ASCII forms of Modbus

Receive Buffer Size

This property is of type Unsigned integer and can be referenced with the variable name ReceiveBufferSize.

Maximum number of bytes the receive buffer can hold

Slave ID Bytes

This property is of type Unsigned integer and can be referenced with the variable name AddressBytes.

Number of bytes used when passing a slave ID, usually 1 but sometimes 2

Slave Address

This property is of type Unsigned integer and can be referenced with the variable name SlaveAddress.

No additional information


Reply Delay

This property is of type Unsigned integer and can be referenced with the variable name ReplyDelay.

Delay in micro seconds to wait before transmitting a reply

Label

This property is of type Line of text and can be referenced with the variable name label.

A text label to appear on the Modbus panel object.

Data Source

This property is of type Fixed list of ints and can be referenced with the variable name DataSource.

Simulation data source used to allow the component to connect to COM port hardware or the the data injector components.

COM Port

This property is of type Fixed list of ints and can be referenced with the variable name COM_port.

COM port assigned to allow the simulation to communicate with actual Modbus hardware.

Starting Address

This property is of type Unsigned integer and can be referenced with the variable name StartAdrCoil.

Start address of the Modbus coils. Referenced from 0.

For example

Slave 1 might have 100 coils addressed 0-99 Start Address = 0

Slave 2 might have 100 coils addressed 100-199 Start Address = 100

Number of Addresses

This property is of type Unsigned integer and can be referenced with the variable name NumAdrCoil.

Specifies how many Coils are available on the slave.

Each address consumes a single bit of RAM, 8 Addresses are packed together into a single RAM Byte.

Starting Address

This property is of type Unsigned integer and can be referenced with the variable name StartAdrDI.

Start address of the Modbus digital inputs. Referenced from 0.

For example

Slave 1 might have 100 inputs addressed 0-99 Start Address = 0

Slave 2 might have 100 inputs addressed 100-199 Start Address = 100

Number of Addresses

This property is of type Unsigned integer and can be referenced with the variable name NumAdrDI.

Specifies how many Digital Inputs are available on the slave.

Each address consumes a single bit of RAM, 8 Addresses are packed together into a single RAM Byte.

Starting Address

This property is of type Unsigned integer and can be referenced with the variable name StartAdrAI.

Start address of the Modbus analogue inputs. Referenced from 0.

For example

Slave 1 might have 100 inputs addressed 0-99 Start Address = 0

Slave 2 might have 100 inputs addressed 100-199 Start Address = 100

Number of Addresses

This property is of type Unsigned integer and can be referenced with the variable name NumAdrAI.

Specifies how many 16-bit analogue inputs are available on the slave.

Each address consumes two RAM Bytes.

Starting Address

This property is of type Unsigned integer and can be referenced with the variable name StartAdrReg.

Start address of the Modbus registers. Referenced from 0.

For example

Slave 1 might have 100 registers addressed 0-99 Start Address = 0

Slave 2 might have 100 registers addressed 100-199 Start Address = 100

Number of Addresses

This property is of type Unsigned integer and can be referenced with the variable name NumAdrReg.

Specifies how many 16-bit holding registers are available on the slave.

Each address consumes two RAM Bytes.

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