Rockwell Automation 1771-PD PID MODULE (+DU) - Manual (Page 37)

Assembly and Installation
Chapter 2
2Ć24
The PID module has internal pico fuses to protect circuitry from surges in
the optional +5V dc supply., A blown fuse condition is indicated when
none of the front panel LED indicators turn on after you turn on this
supply. If the LEDs do not turn on, check programming plugs E23 and
E24. These plugs allow you to select the source of +5V dc from the
backplane or from an external supply. Incorrect positioning of these plugs
can prevent the LEDs from turning on even when pico fuses are OK.
Check that E23 and E24 are in the correct position for using the external
+5V dc supply (Table 2.D and Figure 2.3).
If the fuses are blown, we recommend that you return the module for
factory repair through your nearest field service or sales office.
Unauthorized repair of these fuses could result in damage to other circuit
components and void your warrantee.
Precautions
Take the following precautions to avoid blowing these fuses:
Be sure that the optional +5V dc supply is connected correctly to field
wiring arm terminals (Figure 2.4).
Be sure that the optional +5V dc supply meets specifications
(Table 2.G), especially for surge voltage at turn on.
Supply +5V dc to each PID module using one or more optional external
power supplies.
Place an on/off switch in the +5V dc lead to each PID module. This
allows you to remove power and replace a PID module without turning
off power to other PID modules in the chassis.
Remove power from the PID Module’s field wiring arm before
connecting or disconnecting the arm.
We make the following recommendations for removing one of several
PID modules from an I/O chassis.
WARNING: Remove power from a field wiring arm before
connecting or disconnecting it. Turn off power to the I/O
chassis before inserting or removing any of its modules. Failure
to observe this warning can result in damage to module circuitry
and/or unpredictable operation of other modules in the chassis
with possible damage to equipment and/or injury to personnel.
Internal Fusing
Recommendations for Installing
or Removing Modules