CANopen:CAN PDO READ
Return contents of recent PDO message to from the slave.
System stores most resent PDO message from every slave, with each PDO reference counter is incremented.
Reference counter shall be used for detection a new data.
Input
Dadd - drive address
pdo number - 1..4
Offset - offset in PDO from where data will be copied
Size - how many bytes to copy 1..4
Output
lRefCnt - reference counter - increments each PDOx is recieved
Return Value
PDO data copied from offset and size
Declaration
public function CAN_PDO_Read(byval lDadd as long , byval lpdo as long,byval lOffset as long,byval lSize as long, lRefCnt as long) as long
Syntax
PdoData = CAN_PDO_Read(<Dadd>,<pdoNum>,<Offset>,<size>,RefCnt)
Limitations
Signed 8 and 16 bit objects are not properly converted to LONG. For example 8-bit negative value, eg. -3, read as 253. Application shall apply sign extension for negative 8/16 bit objects.
Exceptions
Examples
program
dim lRefCnt as long=0
dim lPdoVal as long=0
lPdoVal = CAN_PDO_Read(1 , 1,0,2, lRefCnt)
print "LValue ",lPdoVal hex,"ref count=",lRefCnt
lPdoVal = CAN_PDO_Read(1 , 4,0,2, lRefCnt)
print "LValue ",lPdoVal hex,"ref count=",lRefCnt
lPdoVal = CAN_PDO_Read(1 , 1,0,2, lRefCnt)
print "LValue ",lPdoVal hex,"ref count=",lRefCnt
end program ' <MyTask>.prg