Reading an invalid entry
Let’s assume that there are only 2 alarms present in the system. Then reading alarm entry #3 should return an invalid
entry
Field Value Description
Function 4 (0x04) Read input register
Address 2014 (0x07DE) 2010 + 2*(3-1) = 2014 (see alarm table, page 83)
Number of registers 2 (0x02) Alarm entry is 2 registers wide
Master frame: 0x01 0x04 0x07 0xDE 0x00 0x02 0x10 0x85
T2S ETH frame: 0x01 0x04 0x04 0xFF 0xFF 0xFF 0xFF 0xFA 0x10
Conclusion, there is no alarm entry #3 and nor are there further entries. This leads to the conclusion that only 2 alarms
are present at the time in the system.
Linking alarm ID to alarm description text:
If we consider the alarm ID #179 of example above, we can get description text for this alarm by reading related entry
in the “Event string table”.
Field Value Description
Function 4 (0x04) Read input register
Address 18092 (0x46AC) 16660 + 8*179 = 18092
Number of registers 8 (0x08) Event description string is 16 characters long
Master frame: 0x01 0x04 0x46 0xAC 0x00 0x08 0x24 0xA5
T2S ETH frame: 0x01 0x04 0x10 0x56 0x61 0x63 0x5F 0x69 0x6E 0x20
0x54 0x4F 0x4F 0x20 0x4C 0x4F 0x57 0x20 0x20 0x36 0x7C
String description: Vac_in TOO LOW
87 – Monitoring T2S - ETH User Manual – v1.4
Annex 3: Modbus
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