Endress+Hauser Liquiline CM444 - Page 77

Liquiline CM442/CM444/CM448 Operation
Endress+Hauser 77
Outputting the manipulated variable of a controller
To output a controller manipulated variable via a relay, the relay is modulated. The relay is
energized (pulse, t
1
) and is then de-energized (interval, t
0
).
Types of modulation:
1. PWM (pulse width modulation):
The duty cycle is varied within a period T (T=t
1
+t
0
). The cycle duration remains constant.
Typical application: solenoid valve
Function="Controller"
Function Options Info
Source of data Options
•None
• Controller 1
• Controller 2
Factory setting
None
Select the controller that should act as the data source.
Operating mode Options
•PWM
•PFM
Factory setting
PWM
PWM=pulse width modulation
PFM=pulse frequency modulation