Allen-Bradley 1732ES-IB16 - Page 56

56 Rockwell Automation Publication 1791ES-UM001G-EN-P - November 2016
Chapter 3 Install the Module
Most 1732ES modules require two 24V DC (nominal) supplies. These
supplies are called the ‘input +24V DC power’ and the ‘output +24V DC
power’. The input +24V DC power provides power for the module control and
Ethernet portions of the module, the safety input/test output circuits, and the
test output loads. The output +24V DC power provides power for the safety
output circuits and the safety output loads. Since the 1732ES-IB16 module has
no safety outputs, it requires only one 24V DC (nominal) power supply to
provide ‘input +24V DC power’.
Internally, the input +24V DC power and output +24V DC power are isolated
from each other.
The input +24V DC power current that is required for a module in the daisy
chain can be estimated as described here.
I
IP
~ I
IPM
+ I
TO
+ I
IPDC
Where:
I
IP
is the input +24V DC power current through the male power connector of
the module.
I
IPM
is the input +24V DC power current required by the module itself (with
no test output load current).
I
TO
is the total test output load current for test outputs N (0…11).
I
IPDC
is the total input +24V DC power current through the female power
connector of the module (input +24V DC power current for the modules that
follow in the daisy chain).
I
IPM
can be approximated by dividing the number of watts for each type of
1732ES module by +24V DC as listed here:
• 1732ES-IB12XOB4, 1732ES-IB12XOBV2 = 4.2 W
• 1732ES-IB8XOB8, 1732ES-IB8XOBV4 = 3.96 W
• 1732ES-IB16 = 4.56 W
The table input +24V DC power calculation shows an example input
+24V DC power current calculation for a system of four 1732ES-IB12XOB4
modules. The input +24V DC power voltage is 24V DC in this example.
Module 1 is the first module in the daisy chain. Fill out the table by starting
with the last module in the daisy chain, in this example Module 4. Once I
IP
is
calculated for module 4, it transfers as the I
IPDC
value for Module 3. This
process continues for all modules in the daisy chain.
IMPORTANT The maximum current that any pin on the power connectors can carry is
10 A.