Rockwell Automation 1797-XXX FLEX Ex System Certification Reference Manual - Manual (Page 181)

Publication 1797-6.5.6 - June 2005
ControlNet Ex System 39-5
If fiber optic cable is provided with a metal shield, it must be connected to
a dedicated intrinsic safety ground in the non-hazardous location and tied back
in the hazardous location or be connected to a ground in the hazardous
location and tied back in the non-hazardous location.
The glass fiber must have a minimum diameter of 6µm.
The ControlNet Ex tap must be connected directly to the module (no
additional cable may be connected).
Must be FM approved.
Total coax trunk cable length is limited to 1000m (3280 ft) with up to 2
ControlNet Ex taps connected and to 250m (820 ft) with the maximum
allowed ControlNet Ex taps of 48. For ControlNet Ex taps between 2 and 48
use: 1000m (3280 ft) - 16.3m (53.4 ft) x (number of taps - 2) to find the
maximum allowed cable length.
Power supplies are suitable for mounting in Class I, Division 1, Groups
B-D or Class I, Zone 1, Group IIC.
The maximum number of 1797-ACNR15 modules that can be connected
to one system is 47.
The maximum number of 1797-RPA modules that can be connected to
one system is 47.
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