Tecomat TC600
TXV 138 08.02 86
Full description of the instruction set is given in the handbook
Instruction
Set of Tecomat PLC, TXV 001 05.02
11. Diagnostics and Removal of Faults
The Tecomat PLC diagnostic system is a part of the standard sw and hw
equipment of the PLC's. It is active starting from turning on of the PLC
power supply and operates independently of the user. The main function is
ensuring of error-free and accurately defined function of the PLC in any
situation. The system continuously follows vitally important parts and func-
tions of the PLC and ensures servicing of an error state immediately in the
moment of its occurrence and informs about the fault.
In the case a fault arises within the PLC, the diagnostic system must es-
pecially eliminate the possibility of origination of breakdown states in the
technology connected to the PLC.
Another task of the diagnostic system is to make easier removal of the
arise fault to service workers or to the user, respectively.
Besides basic functions, the diagnostic system notifies the user of any
possible erroneous manipulations or procedures at the PLC attendance due
to which working with the PLC becomes easier and more efficient.
11.1 Conditions for Proper Function of the Diagnostics
The basic condition for error-free function of the PLC and proper ope-
ration of its diagnostics is proper functions of the power supply and of the
central unit.
After turning on of the supply, basic checking of the system kernel is
performed within the initialization. If an error of the EPROM or RAM system
memory is found, the diagnostic system cannot continue in its operation.
This state is signalled by lighting the letter E or t on the display.
11.2 Indication of Errors
The central unit is equipped with the main error stack which contains 8
last error codes announced by the diagnostics of the whole PLC and a local
stack containing 8 last error codes announced by the diagnostics of servic-
ing of inputs, outputs, and communication through the serial channels.
Full error code in the main error stack is 4 bytes long. The first byte gives
the basic error code (it determines the group of faults), the following 3 bytes
give close specification of the error.
Full error code in the local error stack is 2 bytes long. The first byte gives
the basic error code (it determines the group of faults), the second byte
gives closer specification of the error.
Contents of both error stacks are available from the xPRO development
environment. Codes of serious errors are shown on the display at the mo-
ment of their evaluation in the format:
E - label followed with the full error code in hexadecimal form
80 - basic error code
09 00 00 - closer error specification
11.3 Serious Errors
In the case of the rise of a serious error, the diagnostic system blocks the
outputs first, interrupts execution of the user program, and then it identifies
the arisen fault. The full error code is shown on the display and stored in the
main error stack.
Indication of such an error can be cancelled by a command from the su-
perior system or by turning off and on of the PLC power supply.
The PLC diagnostic
system
Error stacks
Indication of errors
PLC behaviour in the
case of a serious
error
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