Rockwell Automation 1760-xxxx Pico Controller User Manual - Manual (Page 186)

Publication 1760-UM001D-EN-P - September 2005
10-2 Troubleshoot Your Controller
Possible Situations When
Creating Circuit Diagrams
Possible Situations When
Creating Circuit Diagrams Explanation Remedy
Cannot enter contact or relay
in circuit diagram Pico is in Run mode Select Stop mode.
Time switch switches at
wrong times Incorrect time or time switch
parameters Check time and
parameters.
Cannot select analog
comparator ‘Ax’ Pico ac versions have no analog
inputs Use Pico dc for
comparing analog
values.
Cannot select time switch
contacts Pico has no clock ‘-NC’ version does
not have a clock.
When using a memory
module Pico will display the
message ‘PROG INVALID’ Pico memory module contains no
circuit diagram Change the version
of Pico or change the
circuit diagram in
the memory module.
Circuit diagram on the memory
module uses contacts /relays that
Pico does not recognize:
• Do not use “-NC” versions
for time switch functions
• Analog inputs only with DC
controllers
Current flow display does not
show modifications to the
circuit connections Pico is in Stop mode Select Run mode.
Operation / connection not
performed Check the circuit
diagram and
parameter sets and
modify as required.
Relay does not activate coil
Incorrect parameter values / time
• Analog value comparison
is incorrect
• Time value of timing relay
is incorrect
• Function of timing relay is
incorrect
Relay ‘Q’ or ‘M’ does not pick
up Relay coil has been wired up
several times Check coil field
entries.
Input not detected Loose terminal contact Check installation
instructions, and
external wiring.
No voltage to switch/button
Broken wire
Pico input is faulty Replace the Pico.