D-1
S7-200 Programmable Controller System Manual
A5E00066097-02
S7-200 Troubleshooting Guide
Table D-1 S7-200 Troubleshooting Guide
Problem
Possible Causes Solution
Outputs stop
working.
• The device being controlled
has caused an electrical surge
that damaged the output.
• User program error
• Wiring loose or incorrect
• Excessive load
• Output forced points
• When connecting to an inductive load (such
as a motor or relay), a proper suppression
circuit should be used. Refer to Section 2.4.
• Correct user program
• Check wiring and correct
• Check load against point ratings
• Check CPU for forced I/O
CPU SF
(System Fault)
light comes on.
The following list describes the
most common causes:
• User programming error
– 0003 Watchdog error
– 0011 Indirect addressing
– 0012 Illegal floating point
value
• Electrical noise
– 0001 through 0009
• Component damage
– 0001 through 0010
Read the fatal error code number and refer to
Section B.1:
• For a programming error, check the usage of
the FOR, NEXT, JMP, LBL, and Compare
instructions.
• For electrical noise:
– Refer to the wiring guidelines in
Section 2.3. It is very important that the
control panel is connected to a good
ground and that high voltage wiring is not
run in parallel with low voltage wiring.
– Connect the M terminal on the 24 VDC
Sensor Power Supply to ground.
Power supply
damaged.
Over-voltage on the power lines
coming to the unit.
Connect a line analyzer to the system to check
the magnitude and duration of the over-voltage
spikes. Based on this information, add the proper
type arrestor device to your system.
Refer to the wiring guidelines in Section 2.3 for
information about installing the field wiring.
Electrical noise
problems
• Improper grounding
• Routing on wiring within the
control cabinet.
• Input filters are configured for a
speed that is too fast
Refer to the wiring guidelines in Section 2.3. It is
very important that the control panel is connected
to a good ground and that high voltage wiring is
not run in parallel with low voltage wiring.
Connect the M terminal on the 24 VDC Sensor
Power Supply to ground.
Increase the input filter delay in the system data
block. Refer to Section 5.2.
D
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