Seite 32
RS485 Interface
capaNCDT 61xx/IP
5.2.3
Example of the Measuring Value Transmission
Master: Request Data
Byte:
SD
DA
SA
FC
FCS
ED
Value:
0x10
x
x
0x4C
x
0x16
FCS
DA = Destination address = slave address = 0x7E
SA = Source address = master address = 0x01
FCS = Checksum = 0x7E+0x01+0x43 = 0xC2
Slave: Response Data
Byte:
SD
LE
LE
rep
SD
rep
DA
SA
FC
Data
FCS
ED
Value:
0x68
0x13
0x13
0x68
0x01
0x7E
0x08
e.g.
16 bytes
x
0x16
FCS
LE = Length = 16 data bytes + 3 bytes (DA, SA, FC) = 19 bytes = 0x13
DA = Destination address = master address = 0x01
SA = Source address = slave address = 0x7E
FCS = Checksum = 0x01 + 0x7E + ….