Rockwell Automation 1797-XXX FLEX Ex System Certification Reference Manual - Manual (Page 40)

Publication 1797-6.5.6 - June 2005
3-2 1797-TB3 FLEX Ex Terminal Base Unit
Inputs Do not apply any non-intrinsically safe signals to the terminal base.
When using as an intrinsically safe electrical apparatus according to EN50020,
the European directives and regulations must be followed.
The terminals in the terminal base unit may be electrically connected to each
other by the insertion of FLEX Ex I/O modules. See the module installation
instructions to determine this.
Description The 1797-TB3 terminal base has 36 wiring connections to/from a plug-in
module. The use of each terminal depends on the module mounted in this
base.
The 1797-TB3 terminal base also has connections for cold junction
compensation and terminals designated for shield termination to chassis
ground.
The terminal base is equipped with a factory-installed tab cover for the
backplane bus connection. The tab cover may be removed only when the
terminal base unit is connected to other terminal base units..
IMPORTANT
When interconnecting several lines, you must consider the
total accumulated power and check for intrinsic safety
requirements.
ATTENTION
• Make certain that you power the terminal base unit with
an intrinsically safe power supply. Do not exceed the
values listed in the specifications for the terminal base
unit.
• Do not use the unused terminals on the terminal base
unit. Using these terminals as supporting terminals can
result in damage to modules and/or unintended
operation of your system.
Wiring Connections for Terminal Base 1797-TB3
0 1 3 2 4 5 6 7 8 9 10 11 12 13 14 15
26 27 28 29 30 31 32 33 25 24 23 22 21 20 19 18 17 16
44 45 46 47 48 49 50 51 43 42 41 40 39 38 37 36 35 34
41252
+V -V -V +V
A
B
C
No connections allowed to terminals 36 and 49