KROHNE Summit 8800 Vol 3 - Manual (Page 146)

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SUMMIT 8800 COMMUNICATION 08
Figure 197 Enron Modbus alarms
For each Alarmed Id a selection can be made from all the possible alarms.
Every cycle the Modbus Alarms are verified, and if the alarm status changes from a previous
cycle, an entry is made in the relevant Event Log. The alarms set the following bits within the
Modbus Log Event bitmap register.
Events are a result of a preset value change, and are generated by examining values in the Mod-
bus setup. These IDs do not necessarily have to be present in the Alarmed ID list.
8 .6 Pemex Modbus
Pemex modbus is, similar to Enron modbus, designed to read logs via Modbus. In this case also
batch logs are defined and the addressing scheme is slightly different.
8 .6 .1 Logs
All logs need to be kept for 35 days. This means that the sizes for:
• Daily logs: 35 entries
• Hourly log: 35x24= 840 entries
• Batch logs 35x10= 350 entries
• Event log entries of 255 entries
8 .6 .2 Addressing scheme
The following addressing scheme should be used:
Adresses Variables Read command Write command
0001-1000 History Logs 03
0032 Event log 03 05 (acknowledge)