Xylem CL500 ONLINE CHLORINE ANALYZERS MODBUS - Manual (Page 10)

4.3 Holding Registers
These 16-bit values are readable and changeable from the master. The data is stored and
transmitted with the MSB first and then the LSB.
4.3.1 Valid Command(s)
Code Name Broadcast
0x03 Read Holding Registers No
0x06 Preset Single Register Yes
0X16 Preset Multiple Registers Yes
4.3.2 Format
Float – stored in two consecutive addresses, with the first address containing the least significant
word (lower part of mantissa) and the second address containing the most significant word (sign,
exponent, and upper part of mantissa).
4.3.3 Valid Addresses
40001 – 40XXX
4.3.4 Definitions
Address Type Register Min Default Max Function
40001 Int Decimal places 0 2 3 0 – XXXXX
1 – XXXX.X
2 – XXX.XX
3 – XX.XXX
40002 Int Units (scaling) 0 0 1 0 – PPM
1 – MG/L
40003 Int # of Readings 1 2 5 Number of Readings
Used in Averaging
40004 Int LCD backlight 1 8 10 Higher is brighter
40005, 40006 Float 4-20 mA
minimum value
0.0 0.00 10.0 Scaling value
40007, 40008 Float 4-20 mA
maximum value
0.0 6.00 10.0 Scaling value
40009 Int 4-20 mA error
alarm output 0 2 3 0 – Off
1 – 0 mA
2 – 2 mA
3 – 4 mA
40010 Int RS-485 baud 0 3 4 0 – 1,200
1 – 2,400
2 – 4,800
3 – 9,600
4 – 19,200
40011 Int RS-485 data bits 0 1 1 0 – 7 bits
1 – 8 bits
40012 Int RS-485 parity 0 0 2 0 – None
1 – Even
CL500 Modbus (3/09)
Rev. 1.3 8