S7-200 Troubleshooting Guide - Siemens SIMATIC S7-200 System Manual

S7-200 Troubleshooting Guide

Table D-1 S7-200 Troubleshooting Guide
Problem
Outputs stop The device being controlled
working. has caused an electrical surge
that damaged the output.
User program error
Wiring loose or incorrect
Excessive load
Output forced points
CPU SF The following list describes the
(System Fault) most common causes:
light comes on.
User programming error
– 0003 Watchdog error
– 0011 Indirect addressing
– 0012 Illegal floating point
value
Electrical noise
– 0001 through 0009
Component damage
– 0001 through 0010
Power supply Over-voltage on the power lines
damaged. coming to the unit.
Electrical noise Improper grounding
problems
Routing on wiring within the
control cabinet.
Input filters are configured for a
speed that is too fast
S7-200 Programmable Controller System Manual
A5E00066097-02
Possible Causes Solution
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
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.
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.
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.
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