March 2015
Intermediate to advanced
424 pages
10h 53m
English
This chapter shows how timer blocks, on-delay and off-delay, can be used in programs, also pulse timers and retentive timers. Programs involving such operations are developed.
Keywords
timers
In many control tasks there is a need to control time. For example, a motor or a pump might need to be controlled to operate for a particular interval of time or perhaps be switched on after some time interval. PLCs thus have timers as built-in devices. Timers count seconds or fractions of seconds using the internal CPU clock. This chapter shows how such timer function blocks can be programmed to carry out control tasks.
PLC manufacturers differ on how timers should be programmed and hence how they can ...
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