RLE LD5000 - Manual (Page 80)

Appendix A: Modbus Communication User Guide: LD5000
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Table 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)
…
Crc Checksum (2 bytes)
Table 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
30009 Version Firmware version xx.xx X 100 0-65535
Table 6: Status Flags (Register 30001):
Bit Description
00 1 = Leak is Detected
01 1 = Cable Break Alarm
02 1 = Contamination is detected
03-15 Spare
A-2.3 Function 06: Preset Single Register
To set a LD5000 parameter value, the master must send a Preset Single Register request packet. The Preset Single
Register request packet specifies a register and the data to write to that register. The register is numbered from zero
(40001 = zero, 40002 = one, etc).
Table 7: Preset Single Register Packet Structure
Preset Register Request Packet Preset Register Response Packet
Slave Address (1 byte) Slave Address (1 byte)
06 (Function code) (1 byte) 06 (Function code) (1 byte)
Register (2 bytes) Register (2 byte)
Data (2 bytes) Data (2 bytes)
Crc Checksum (2 bytes) Crc Checksum (2 bytes)