ComBricks User Manual v6.4.0 | January 18| © PROCENTEC 133/219
12.5.3 Spur lines
The trunk line on the PA module can have up to 32 spur lines with the following lengths:
Table 10 - Spur lines
The PROFIBUS PA specification allows up to 3 devices on a spur. Please refer to paragraph 12.5.1 for an
explanation on how to connect the PA trunk to the PA module.
12.5.4 Current consumption calculations
The PA module provides a maximum of 500mA to the PA trunk. The total current consumption of all slaves on
this trunk cannot exceed 500mA. The PA module consumes 10mA. At least one FDE (Fault Disconnection
Electronics, stated in the manual of the PA device) should also be calculated . The calculation for the current
consumption is as follows:
See Fig. 88 for an example.
I
SEG
= I
B0
+ I
B1
+ .. + I
BN
+ I
FDE
I
SEG
= Total current in a segment
I
BN
= Basic current of devices
I
FDE
= Current of the Fault Disconnection Electronics