12
3-4. Connecting the measuring unit
Devices can be connected to the Foundation Fieldbus™ in two ways:
Connection via conventional cable gland
→
Connection via fieldbus connector (optional, can be purchased as an accessory)
→
Handling Precautions:
Risk of damaging
f
Switch off power supply before installing or connecting the head transmitter.
Failure to observe this may result in destruction of parts of the electronics.
f
Grounding via one of the grounding screws (terminal head, field housing) is
recommended.
f
If the shielding of the fieldbus cable is grounded at more than one point in
systems without additional potential matching, power supply frequency
equalizing currents can occur that damage the cable or the shielding. In such
cases the shielding of the fieldbus cable is to be grounded on only one side,
i.e. it must not be connected to the ground terminal of the housing (terminal
head, field housing). The shield that is not connected should be insulated!
f
We recommend that the fieldbus not be looped using conventional
cable glands. If you later replace even just one measuring device, the bus
communication will have to be interrupted.
3-4-1. Cable glands or entries
Please also observe the general procedure on page 6.
Fig. 3-3. Connection to the F
oundation
Fieldbus™ fieldbus cable - installed
in the field housing on the left, and in the terminal head on the right
A FF terminals - fieldbus communication and power supply
B Inner ground terminal
C Outer ground terminal
D Shielded fieldbus cable (Foundation Fieldbus™)
