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Automating Manufacturing Systems - Process Control and ...

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plc timers - 9.32<br />

9.10 PRACTICE PROBLEM SOLUTIONS<br />

1. edge triggered means the event when a logic signal goes from false to true (positive edge) or<br />

from true to false (negative edge).<br />

2. no, but they are essential for retentive timers, <strong>and</strong> very important for counters.<br />

3. Timers on PLC-5s <strong>and</strong> Micrologix are 16 bit, so they are limited to a range of -32768 to<br />

+32767. <strong>Control</strong>Logix timers are 32 bit <strong>and</strong> have a range of -2,147,483,648 to 2,147,483,647.<br />

4. the un underflow bit. This may result in a fault in some PLCs.<br />

5.<br />

first pass<br />

stop<br />

U<br />

motor<br />

start<br />

L<br />

motor<br />

start<br />

motor<br />

stop<br />

motor<br />

6.<br />

input<br />

TON<br />

delays turning on<br />

TOF<br />

delays turning off<br />

www.PA<strong>Control</strong>.com

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