Systematic Repairs in the Event of Malfunction

In the event of an inadvertent interruption, repairs are to be carried out according to the following plan (Picture 1):

Picture 1: Systematic repairs

Prerequisite for systematic repairs

The basic prerequisite for systematic repairs and fault finding is knowledge of the system. This means that only when you have familiarised yourself with the system and know how it is structured, will you be able to carry out systematic repairs. Familiarisation with the system by:

>> closely observing the installation;
>> making available the entire system documentation;
>> knowing the product and processing technology;
>> exchanging information with the user, operator.


Structuring of the system into:

1. System and controller structure

>> Program flow charts
>> Function charts
>> Description

2. Mechanical design

>> Structure and support unit
>> Function units
>> Adjustment

3. Drive technology

>> Electrical system
>> Hydraulics
>> Pneumatics
>> Mechanical system

4. Final control element

>> same as 3

5. Control system

>> Electrical relay control
>> Programmable logic controller

6. Signal generator

>> Binary sensors
>> Analogue sensors
>> Digital sensors

7. Power supply

>> Electrical
>> Hydraulic
>> Pneumatic

Procedure

The first thing that must be done in the event of an error signal is to establish the actual status. The following options are available for this:

>> Discussing the fault with the user (Does the system operate incorrectly?);
>> Start failure;
>> Stopping during process step;
>> Faulty process;
>> Incorrect working practice.