2. Pivot the top of the cover further to release it
from the lower two latches.
3. Replace the cover by placing it squarely over
the base, and then gently and evenly push the
cover on to the latches until they snap into the
latched position.
Figure 9: Controller with cover removed
Setting the End-of-Line (EOL) switch
Each expansion module has an EOL switch. When
the EOL switch is set to ON, it sets the expansion
module as a terminating device on the bus. See
Figure 10 for the EOL switch location. The default
EOL switch position is OFF.
Figure 10: End-of-Line switch positions
To set the EOL switch on an expansion module,
complete the following steps:
1. Determine the physical location of the
expansion module on the SA or FC bus.
2. Determine if the expansion module must be set
as a terminating device on the bus.
Note:
The EOL termination rules for SA
buses and FC buses are different. Refer to
the
MS/TP Communications Bus Technical
Bulletin (LIT-12011034)
for detailed information
regarding EOL termination rules and EOL
switch settings on SA and FC buses.
3. If the expansion module is a terminating device
on the FC bus, set the EOL switch to ON. If the
expansion module is not a terminating device
on the bus, set the EOL switch to OFF.
When an expansion module is connected to power
with its EOL switch set to ON, the amber EOL LED on
the expansion module cover is lit.
UI current loop jumpers
The UI current loop fail-safe jumpers are on the
circuit board under the expansion module cover
near the UI terminals. When a UI is defined (in the
system software) as a 4 to 20 mA Analog Input
and the UI’s current loop jumper is in the Disabled
(default) position (Figure 11), the 4 to 20 mA current
loop circuit opens whenever power to the expansion
module is interrupted or off.
Figure 11: Current loop jumper positions
Setting the current loop jumper to the Enabled
position (Figure 11) connects an internal 100 ohm
resistor across the UI terminals, which maintains the
4 to 20 mA current loop circuit even when power to
the expansion module is interrupted or off.
Important:
Current Loop jumpers must be in
the Disabled (default) position for all UIs that
are not set up to operate as 4 to 20 mA analog
inputs.
Table 7: UI Inputs and Jumper Labels
Universal Input Label
Jumper Label on Circuit Board
Label
IN1
J1
IN2
J2
IN3
J3
IOM2723 Input/Output Module Installation Guide
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