Mounting on Terminal Units TU517 or TU518

The assignment of the terminals 1.0 - 1.9:

Terminal	Signal	Description
1.0	B	Data line B (receive and send line, positive)
1.1	B	Data line B (receive and send line, positive)
1.2	A	Data line A (receive and send line, negative)
1.3	A	Data line A (receive and send line, negative)
1.4	TermB	Bus termination data line B
1.5	TermB	Bus termination data line B
1.6	TermA	Bus termination data line A
1.7	TermA	Bus termination data line A
1.8	DGND	Reference potential for data transmission
1.9	DGND	Reference potential for data transmission

At the line ends of a bus segment, termination resistors must be connected. If using TU517/TU518, the bus termination resistors can be enabled by connecting the terminals TermA and TermB to the data lines A and B (no external termination resistors are required, see illustration below).

Note

If using TU517/TU518, note that the termination resistors are not located inside the TU, but inside the Bus Module CI541-DP. I. e. when removing the device from the TU, the bus termination resistors are not connected to the bus any more. The bus itself will not be disconnected if a device is removed.

If using TU517/TU518 the max. permitted baud rate is limited to 1,5 MBaud.

Note

The earthing of the shield should take place at the switch-gear cabinet, see System Data AC500 System Data AC500.