GE GFK-0787B user manual Genius Bus Connections, Termination Boards

8

Genius Bus Connections

When planning and installing a Genius bus, it is extremely important to follow the guidelines given in the Genius I/O System and Communications User's Manual. That manual describes correct cable types, wiring guidelines, bus length, bus termination, baud rate, and bus ambient electrical information.

In GMR system, ªGMR bussesº can operate at any baud rate with the following restrictions:

D.All busses in a group must use the same baud rate.

E.Each individual GMR bus must have a scan time of 60 milliseconds or less.

Bus cable connections to a Genius block in a GMR system should be made in such a way that a block's terminal assembly can be removed from the bus during system operation without ªbreakingº the bus and disrupting communications.

To do that, the bus can be installed at each block using an intermediate connector, as shown below.

I

N

O

U

T

S1

S2

SHLD IN

SHLD OUT

'

S1

S2

SHLD IN

SHLD OUT

An alternative method, but somewhat less desirable, is to solder together the corresponding wire ends before inserting then into the block's terminals. If such soldered wires are removed while the system is operating, it is important to cover the ends of the wires with tape to prevent shorting the signal wires to one another or to ground.

Both of these installations allow a block's terminal assembly to be removed while maintaining data integrity on the bus.

When blocks are connected to the bus in this manner, field wiring to the blocks should also provide a means of disconnecting power to individual blocks.

Termination Boards

Termination boards that will make it easier to integrate Genius blocks into redundant groups (4-block output groups or 3 or 2 block input groups) are currently being developed by a third-party supplier. Please contact your GE Fanuc Sales representative for more information about these GMR Termination Boards.

8-2	GeniustModular Redundancy Flexible Triple Modular Redundant (TMR) System	GFK-0787B
	User's Manual ± March 1995