Rules for Failsafe Operation of an S5-95F
S5-95F
18.1.2 Pre-Acceptance Inspection
Normally, the documents listed below must be handed over at a pre-acceptance test. The
documents must be released by the operator/installation engineer and must include the system,
version and date.
•
Component mounting diagrams, including specification of the module version
•
A printout of the configuring data made with COM 95F, and a data carrier containing these data
•
Logic and signal flow diagrams
•
Program flow diagrams, program overview and the user program in form of a test file (see the
COM 95F Manual), with data blocks on a data carrier and as KOMDOK listing
•
A cross-reference list of all inputs, outputs, flags, timers, counters, blocks and I/Os
•
Certification report and conditions of the prototype test
Checking of the System Parameters
Use a COM 95F printout to prove that all values relevant to failsafety fulfill the safety requirements.
The monitored cycle time must in all cases be reflected in the required processor response times.
Checking of the Configured Hardware
The inspector uses the component mounting diagram and the printout of the configuring data to
make sure that all safety-relevant input and output modules are failsafe. This applies not only to the
input and output modules, but also to sensors and actuators.
Checking of the User Program
The inspector checks the user program on the basis of the program listing, the flowcharts and the
logic diagrams.
Among other things, he checks
•
For proper conversion of the logic diagrams
•
The parameter initialization and use of the integral blocks
•
The parameter initialization and use of the standard function blocks
•
The failsafe formation of the safety-related outputs, timers and counters.
Outputs, timers and counters are regarded as failsafe when the input parameters used for them
are failsafe or when, after viewing an error, it could be proven that the arbitrary fallibility of a
non-failsafe input parameter can in no case lead to an unsafe state.
Checklist for the Acceptance Inspection
We would recommend a checklist which includes, among other things,
•
Objectives as far as failsafety is concerned
•
Function tests for safety-relevant functions
•
Conditions of the prototype test
and
•
Conditions of the automated process
18-4
EWA 4NEB 812 6210-02
