Hardware Troubleshooting Guide - Siemens Simatic S7-200 System Manual

Hardware Troubleshooting Guide

Table 8-1 Troubleshooting Guide for the S7-200 Hardware
Symptom
Outputs stop working
SF (System Fault) light on the
S7-200 turns on
None of the LEDs turn on
Intermittent operation
associated with high energy
devices
Communications network is
damaged when connecting to
an external device
Either the port on the
computer, the port on the
S7-200, or the PC/PPI cable is
damaged
Other communications
problems (STEP 7–Micro/WIN)
Error handling
Hardware Troubleshooting Guide and Software Debugging Tools
Possible Causes
H
The device being controlled has
caused an electrical surge that
damaged the output
H
User program error
H
Wiring loose or incorrect
H
Excessive load
H
Output point is forced
The following list describes the most
common error codes and causes:
H
User programming error
– 0003 Watchdog error
– 0011 Indirect addressing
– 0012 Illegal floating-point
value
– 0014 Range error
H
Electrical noise
(0001 through 0009)
H
Component damage
(0001 through 0010)
H
Blown fuse
H
Reversed 24 V power wires
H
Incorrect voltage
H
Improper grounding
H
Routing of wiring within the control
cabinet
H
Too short of a delay time for the
input filters
The communications cable can provide
a path for unwanted currents if all
non-isolated devices, such as PLCs,
computers, or other devices that are
connected to the network do not share
the same circuit common reference.
The unwanted currents can cause
communications errors or damage to
the circuits.
Refer to Chapter 7 for information about network communications.
Refer to Appendix C for information about error codes.
Possible Solution
H
When connecting to an inductive load (such as a
motor or relay), a proper suppression circuit
should be used. Refer to Chapter 3.
H
Correct user program
H
Check wiring and correct
H
Check load against point ratings
H
Check the S7-200 for forced I/O
Read the fatal error code number and refer to
Appendix C for information about the type of error:
H
For a programming error, check the usage of the
FOR, NEXT, JMP, LBL, and Compare instructions.
H
For electrical noise:
– Refer to the wiring guidelines in Chapter 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 Chapter 3 for
information about installing the field wiring.
Refer to the wiring guidelines in Chapter 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.
H
Refer to the wiring guidelines in Chapter 3 and to
the network guidelines in Chapter 7.
H
Purchase the isolated PC/PPI cable.
H
Purchase the isolated RS-485-to-RS-485 repeater
when you connect machines that do not have a
common electrical reference.
Refer to Appendix E for information about order
numbers for S7-200 equipment.
Chapter 8
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