Compare Plc To Disk; Run Plc Diagnostics; Display Failed I/O; Show Plc Diagnostic Cell - Siemens SIMATIC TI555 System Manual

Troubleshooting by Using Auxiliary Functions (continued)
Compare PLC
to Disk
Run PLC
Diagnostics

Display Failed I/O

Show PLC
Diagnostic Cell
Troubleshooting
7-4
AUX Function 17 (Compare PLC to Disk) compares program disk and
controller data. It allows you to save and load your VERIFY options to and
from the disk or directory.
AUX Function 20 (run PLC diagnostics) initiates the CPU self-checks. The
CPU must be in PROGRAM mode in order to execute self-tests. The CPU
executes the equivalent of an AUX Function 20 at every power up. If any
area fails, a message detailing the failure is displayed. AUX Function 20
makes the following tests.
Valid RAM locations are verified.
Pre-coded ROM checksum values are checked.
The hardware force function is checked.
Internal timer operation is verified.
AUX Function 25 (display failed I/O) displays the locations of any failed I/O
modules which are capable of diagnosing and indicating failure. Some
modules, such as word and analog modules, report that they have failed if
the user-supplied voltage is not correct.
AUX Function 25 also displays I/O mismatch(es), indicating that one or
more installed module(s) do not agree with the I/O configuration. Verify that
the configuration data for listed modules is correct before considering that
the module may actually be malfunctioning.
AUX Function 29 checks the operational status of the CPU and displays the
results. The display provides the information illustrated in Figure 7-1. Field
descriptions are listed below.
Scan = scan time reported by AUX Function 29; it is the highest scan
time recorded since the last CPU reset, PROGRAM–RUN mode
transition, or user peak resets. Status Word 10 (STW10) contains a
continuously updated report of the scan time.
Key = always unlocked; the CPU does not have a key.
Mode = Run, Program, or Hold; shows the CPU operating mode.
SF/Loop Mode = Run indicates the system is running loops, analog
alarms, and SF programs in the SF/Loop Mode.
TI545/TI555 System Manual