9
3 Product description
VEGACAL 62 • Profibus PA
30025-EN-160331
1
2
3
Fig. 3: Functional principle - Plate capacitor
1 Distance between the electrode surfaces
2 Size of the electrode surfaces
3 Type of dielectric between the electrodes
The probe and the vessel wall are the capacitor plates. The measured
product is the dielectric. Due to the higher dielectric constant of the
product compared to air, the capacitance increases as the probe is
gradually covered.
The capacitance as well as the resistance change are converted by
the electronics module into a level-proportional signal.
Power supply via the Profibus DP/PA segment coupler or VEGALOG
571 EP cards. A two-wire cable according to Profibus specification
serves as carrier of both power and digital data transmission for
multiple sensors. The instrument profile of VEGACAL 62 corresponds
to profile specification version 3.0.
The backlight of the display and adjustment module is powered by the
sensor. Prerequisite is a certain level of operating voltage.
The data for power supply are specified in chapter "
Technical data
".
The optional heating requires its own operating voltage. You can find
details in the supplementary instructions manual "
Heating for display
and adjustment module
".
This function is generally not available for approved instruments.
The GSD (instrument master files) and bitmap files necessary for
planning your Profibus-DP-(PA) communication network are available
from the download section on the VEGA homepage www.vega.com.
There you can also find the appropriate certificates. In a PDM envi-
ronment, an EDD (Electronic Device Description) is also required
to enable the full range of sensor functions (also available as a
download).A CD with the appropriate files can be ordered via e-mail
under [email protected] or by phone from one of the VEGA agencies
under the order number "DRIVER.S".
3.3 Operation
The instrument can be adjusted with the following adjustment media:
•
With the display and adjustment module
Power supply and bus
communication
GSD/EDD
