CRCMB

Action

Returns the Modbus CRC value of a variable or array.

 

 

Syntax

Var = CRCMB( source , L)

 

 

Remarks

Var	The variable that is assigned with the modbus checksum of variable source. This should be a word variable.
Source	The source variable or first element of the array to get the checksum of.
L	The number of bytes to check.

 

CRC8 is used in communication protocols to check if there are no transmission errors.

The Modbus checksum uses a different polynome.

 

Modbus.lbx or modbus.lib need to be included in your project using the $LIB directive

 

 

See also

CHECKSUM , CRC16, CRC16UNI , CRC32 , TCPCHECKSUM , CRC8

 

 

 

 

Example

$regfile = "m48def.dat" ' specify the used micro
$crystal = 8000000 ' used crystal frequency
$baud = 19200 ' use baud rate
$hwstack = 32 ' default use 32 for the hardware stack
$swstack = 10 ' default use 10 for the SW stack
$framesize = 40 ' default use 40 for the frame space
 
Config Com1 = Dummy , Synchrone = 0 , Parity = None , Stopbits = 1 , Databits = 8 , Clockpol = 0
 
Dim Ar(10) As Byte
Dim W As Word
 
Ar(1) = 1
Ar(2) = 2
Ar(3) = 3
 
W = CrcMB(ar(1) , 3) 'calculate value
 
Print W
 
End

Languages	English