Campbell CR10X, Instruction Manual, Page: 347 / 363

Appendix I. Modbus on the CR10 and CR10X
I-3
I.3.1 Example 1: Function 1 to Read Coils 1 to 16 from Slave
Device 17
Hex
Slave address 11
Function 01
Starting Address Hi 00
Starting Address Lo 00
No. of Points Hi 00
No. of points Lo 16
Error check (LRC or CRC) --
The coil status is returned as one coil per bit of the data field. Coils 1 to 16 are
addressed as 0 to 15. Response for example 1 follows:
Binary
Hex 8765 4321
Slave address 11
Function 01
Byte Count 02
Data (Coils 7-0) CD 1100 1101
Data (Coils 15-8) 6B 0110 1011
Error check (LRC or CRC) --
The status of coils 7-0 is CD hex, or 1100 1101 binary. Coil 15 is the Most
Significant Bit (MSB). The CR10’s C1, C3, C4, C7, C8 are on, C2, C5, and C6
are off. Flags 1,2,4,6, and 7 are high.
I.3.2 Example 2: Function 3 to Read Registers 40009 to 40012
from Slave Device 17 to Retrieve Input Locations 5 and 6
from the CR10/10X
Hex
Slave address x11
Function 03
Starting Address Hi 00
Starting Address Lo 09
No. of Points Hi 00
No. of points Lo 04
Error check (LRC or CRC) --