RLE LD5000 - Manual (Page 79)

User Guide: LD5000 Appendix A: Modbus Communication
www.rletech.com 970.484.6510 71
A-2 PACKET COMMUNICATIONS FOR THE LD5000
A-2.1 Function 03: Read Output Registers
To read the LD5000 parameter values, the master must send a Read Output Registers request packet.
The Read Output Registers request packet specifies a start register and the number of registers to read. The start
register is numbered from zero (40001 = zero, 40002 = one, etc).
Table 2: Read Output Registers Packet Structure
Read Registers Request Packet Read Registers Response Packet
Slave Address (1 byte) Slave Address (1 byte)
03 (Function code) (1 byte) 03 (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 3: Output Registers
Register Name Description Units Range
40001 Leak Threshold Trip current for leak alarm uAmps 0-65535
40002 Contamination Threshold Trip current for contamination alarm uAmps 0-65535
40003 Re-Alarm Re-Alarm delay Minutes 0-65535
40004 Latched Alarm Latching Alarms 0=No 1=Yes 0-65535
40005 Silence Alarm Set to 1 to silence audible alarm 1=Silence 0-65535
40006 Reset Alarm Set to 1 to reset alarms 1=Reset Alarm 0-65535
40007 Spare 0-65535
40008 Spare 0-65535
40009 Spare 0-65535
40010 Month Clock 1-12 0-65535
40011 Day Clock 1-31 0-65535
40012 Year Clock 00-99 0-65535
40013 Hour Clock 0-23 0-65535
40014 Minutes Clock 0-59 0-65535
40015 Seconds Clock 0-59 0-65535
40016 Seconds Leak Alarm Delay 20-3600 0-65535
40017 Seconds Contamination Alarm Delay 20-3600 0-65535
A-2.2 Function 04: Read Input Registers
To read the LD5000 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 (40001 = zero, 40002 = one, etc).