Function 04: read input registers, Table 5.4, Read input registers packet structure – RLE LD2100 V.2.6 User Manual
Page 70: Table 5.5, Input registers, 2 function 04: read input registers

70
LD2100 User Guide
800.518.1519
5
Modbus Communication
5.2.2 Function 04: Read Input Registers
To read the LD2100 input values, the master must send a Read Input Registers request packet.
The Read Input Registers request packet specifies a start register and the number of registers
to read. The start register is numbered from zero (30001 = zero, 30002 = one, etc).
40011
Spare
0-65535
40012
Spare
0-65535
40013
Spare
0-65535
40014
Spare
0-65535
40015
Spare
0-65535
40016
Leak Alarm Delay
Leak Alarm Delay
5-995 seconds
0-65535
40017
Contamination Alarm
Delay
Contamination Alarm
Delay
5-995 seconds
0-65535
Table 5.3 Output Registers
Register
Name
Description
Units
Range
Table 5.4 Read Input Registers Packet Structure
Read Registers Request Packet
Read Registers Response Packet
Slave Address (1 byte)
Slave Address (1 byte)
04 (Function code) (1 byte)
04 (Function code) (1 byte)
Start Register (2 bytes)
Byte count (1 byte)
# of registers to read (2 bytes)
First register (2 bytes)
CRC Checksum (2 bytes)
Second register (2 bytes)
…
Cry Checksum (2 bytes)
Table 5.5 Input Registers
Register
Name
Description
Units
Range
30001
Status
Bit level status
None
0-65535
30002
Leak Distance
Location of leak
Ft/Meters
0-65535
30003
Units
Unit of measure
1=Ft 0=Meters
0-65535
30004
Leak Current
Leakage current on
cable
uAmps
0-65535
30005
Cable Length
Installed cable length
Ft/Meters
0-65535
30006
Loop1 Res
Resistance of cable
Ohms
0-65535
30007
Loop2 Res
Resistance of cable
Ohms
0-65535
30008
Res/Ft
Resistance of cable
Ohms x1000
0-65535