Fig. 8: Value input
Currently valid system value
Permissible range of values
Numerical value entry
In the case of numerical value entry, a value is set by entering the individual decimal places. First,
the number to be edited is selected using the left and right keys. Then, the digit can be changed
analogously to the pattern for step-by-step value entry
è
Step-by-step value entry.
4.2
Function
The CMSH is a digital, electropneumatic positioner. It controls the position of a process valve that is
actuated by a pneumatic drive.
The CMSH is a 4 … 20 mA loop powered 2-wire device. An additional power supply is therefore not
required.
The CMSH has a local user interface (LUI) for configuration and operation. A HART interface permits
remote access and integration into higher-level systems.
The CMSH-S-... has an internal position sensor for position/angular detection. The angular position of
the shaft is detected by the internal position sensor.
Alternatively, an external potentiometric position sensor can be connected to the positioner on all
product variants.
4.3 Safety position
The safety position defines the pneumatic initial position of the positioner.
Depending on the product variant and the type of drive, the positioner reacts differently to the failure
of the electrical power supply, the failure of the compressed air supply or an impermissible setpoint
specification.
In the product variant CMSH-...-V-SD-... the pneumatic manifold block CAPS determines the function
type of the positioner and thus the safety position.
To Next Page
Loading...
