Page 29
Appendix | Digital Interface RS485
ACC5703
A 4.2.2
Example Transmission of a Measurement Value
Master: Request data
Byte:
SD
DA
SA
FC
FCS
ED
Value:
0x10
0x7E
0x01
0x4C
0xCB
0x16
FCS
DA = Destination Address = 0x7E = 126 (slave address)
SA = Source Address = 0x01 (master address)
FCS = Checksum
= 0x7E +
0x01 + 0x4C = 0xCB
= 126
+
1 +
76 = 203 (no overflow) at 256)
Slave: Response data
Byte:
SD
LE
LE
rep
SD
rep
DA
SA
FC
Data[]
FCS
ED
Value:
0x68
1B
1B
0x68
0x01
0x7E
0x08
x
0x67
0x16
FCS
4 measured values = 4 x float = 4 x 4 bytes = 16 data bytes
LE = Length = 16 data bytes + 11 bytes (DA, SA, FC, 1xstatus, 4xstatus, 4xcounter, 1xnumber, 2xpadding
byte) = 0x1B = 27
DA = Destination Address = 0x01 (Master)
SA = Source Address = 0x7E = 126 (Slave)
FCS = Checksum = 0x01 + 0x7E + 0x08 + 0x00 (status) + 0x04 (counter) ... = 0x67 (note overflow at 256
each time = reset sum to zero)