Xylem CL500 ONLINE CHLORINE ANALYZERS MODBUS - Manual (Page 8)

4.0 The Modbus RS-485 Output & Commands Implemented
The default communication parameters are 8 bits, no parity and 1 stop bit. Please note that
all Modbus communication is via RS-485. The instruments can support a two wire
multidrop network of 255 units. If the connection is to the master on USB, an RS-485 to
USB converter is required.
4.1 Coils
These single-bit values are readable and changeable from the master. The data will be returned
with the lowest addressed coil in the LSB of the data. Unused bits in the data will be set to 0. True
is a 1 and False is 0.
4.1.1 Valid Command(s)
Code Name Broadcast
0x01 Read Coil Status No
0X05 Force Single Coil Yes
4.1.2 Format
16-bit word format
MSB LSB
Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8 Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
4.1.3 Valid Addresses
00001 – 00XXX
4.1.4 Definitions
Address Function Default
00001 Access code enabled False
00002 RS-485 enabled True
00003 4-20 mA enabled False
CL500 Modbus (3/09)
Rev. 1.3 6