Endress+Hauser Liquiline CM44 series - Activate Fieldbus-Mode Using the Device Menu; Activate Fieldbus-Mode Using Modbus

SD01189C/07/EN/04.17
Endress+Hauser
28 © Copyright Dec. 2016
6.1.1 Activate “Fieldbus”-mode using the device menu
Step
Action
Result
1
Press the soft key “MODE” to enter the
menu in which the operation mode can be
selected.
2
Activate the “Fieldbus mode”.
The operation mode can be changed at any time using the device menu. The setting of the device menu
has priority over the setting by Modbus. This is a safety measure to prevent the start of actions over
Modbus while the analyzer is in operation mode “Manual” during maintenance work.
Important:
A change from “Manual” directly to “Fieldbus” is now allowed by Modbus. Modbus can only change the
operation mode from “Automatic” to “Fieldbus”.
6.1.2 Activate “Fieldbus”-mode using Modbus
The following diagram shows an example sequence without error handling. The application program
should at least consider the following additional cases:
 The analyzer is not reachable by Modbus communication, e.g. because it is switched off
 A write access to a register fails and an exception code is returned in the Modbus reply
 A read access to a registers fails and an exception code is returned in the Modbus reply