Rockwell Automation 1797-CEC FLEX Ex Bus Isolator and Flexbus Connector - Manual (Page 24)

24 FLEX Ex Bus Isolator and Flexbus Connector
Publication 1797-5.13 - June 2010
 I/O module capacitance value is cumulative. Ci (total) = Ci (I/O module
1) + Ci (I/O module 2) + ...Ci (I/O module 8). Ci (total) must be less than
65 F. The limitation of eight I/O modules per isolator is a functional
limitation. Refer to table 2 of the appropriate I/O Modules sections in this
document (1797-6.5.6).
Application
The isolator type 1797-BIC/* module functions as a galvanic isolation barrier
for signals between a nonintrinsic backplane bus and an intrinsic safe
backplane bus. The isolator must be installed in a safe or Zone 2 area.
Cover Plug for IS Backplane Bus
The 16-pole male connector for the FLEX Ex IS backplane bus is provided
with a cover plug. The cover plug can only be removed when a 1797-TB3
terminal base, a 1794-CE1 cable or a 1794-CE3 cable is connected. The
connection must not be connected to any signals that exceed the instrinsically
safe values of the IS backplane.
Power Supply
The isolator is powered via a removable terminal connector with a dc-voltage
between 18V and 32V. Due to a failure in the power supply a maximum
voltage U
m
of 253V ac is permitted.
Isolator Restriction
1797-BIC and -CEC Max of 8 I/O modules
IMPORTANT
For detailed certification information, refer to the FLEX Ex
System Certification Reference Manual, publication
1797-6.5.6.