Rockwell Automation 1797-BCNR FLEX Ex Redundant ControlNet Barrier Module - Manual (Page 10)

10 FLEX Ex Redundant ControlNet Barrier Module
Publication 1797-5.35 - July 2004
2. Connect the redundant ControlNet Ex trunk cable to connector C
after removing the insulator boot.
3. Connect the ControlNet trunk cable to terminal A.
4. Connect the redundant ControlNet trunk cable to terminal D.
5. Install a direct ground wire with a minimum diameter of 4mm 2
between terminal E and the PA Ground (Equipotential System) in the
hazardous area where the ControlNet Ex coax cable is installed.
Do not connect terminal E or the DIN rail to a standard earth ground
connection in the safe area.
When using a 1797-BCNR, the total allowable length of a segment containing
standard RG-6 quad shield cable depends upon the number of nodes in your
segment. There is no minimum trunk-cable section length requirement. The
maximum allowable length of a segment which contains a 1797-BCNR is
500m. (1640 ft.) with two nodes connected (one node on each side of the
1797-BCNR).
Each additional node decreases the maximum length of the segment
according to the plot below. The maximum number of non-redundant media
nodes allowed on a segment is 21 with a maximum length of 250m (820 ft.).
Please note that the maximum number of redundant media nodes on a
segment is 11 with a maximum length of 250m (820ft.).
IMPORTANT
Only remove the 1797-BCNR covers if the ControlNet Ex tap
drop cable is installed.
250
500
21 non-redundant
nodes or 11
redundant nodes
Number of Nodes with One 1797-BCNR
Se
gm
en
t Len
g
th (m)