This example describes monitoring the movement of a cart.
Checks to be carried out:
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check that the Forward order has been correctly entered,
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after receiving the command Forward, ensure that the cart leaves the fcAr sensor before 1 second has passed,
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check that the Forward run-time period does not go beyond 10 seconds,
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check that the 2 sensors at the end of the run are never on 1 at the same time,
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check that the fcAr sensor is on 1 while the cart is at a halt.
Illustration of the application
The drawing below shows the application and the checks that have been carried out:
The application is programmed in text in this example.
%L0:
Advance := Forward AND NOT fcAv;
CondOK := Not (fcAv AND fcAr) AND (fcAr OR Advance OR fcAv)
NfcAr := Not fcAr;
MV_DIA1 (Advance, Forward, CondOK, NfcAr, fcAv, , ,) ;
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EVENT input is used to check that the Forward order has been correctly entered while the cart moves.
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EVENT_T0 input is used to ensure that the card leaves the fcAr sensor before 1 second,
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EVENT_T1 input checks that the run-time does not last longer than 10 seconds,
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COND input is monitored on 1 for the entire time that the DFB is running. It is used to check that:
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the fcAr sensor is on 1 while the is at a stop,
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the two fcAr and fcAv sensors are never on 1 at the same time.
The illustration below shows a graphic representation of the DFB diagnostics as it is hardwired in this example.
