• All outputs in the below examples use a normally open coil, the output of which reflects the input.
• Element naming will be denoted by the letter B and a numerical value unique to the element, for example "B1".
• The images below were extracted from the
Logic creator
and do not show when an element is TRUE or FALSE with
different line colours.
AND
Two normally open contacts connected in series. For the output of a normally open coil to be TRUE, the inputs of both
normally open contacts must be TRUE. This logic can be extended to be used with more than two normally open contacts
connected in series.
Figure 9.6
AND ladder logic diagram
Table 9.7
AND logic truth table
B0
B1
B2
FALSE
FALSE
FALSE
FALSE
TRUE
FALSE
TRUE
FALSE
FALSE
TRUE
TRUE
TRUE
AND logic example
Two open breaker conditions must be met in order to open a circuit breaker.
OR
Two normally open contacts connected in parallel. For the output of the normally open coil to be TRUE, one, or both of the
normally open inputs must be TRUE. This logic can be extended to be used with more than two normally open contacts
connected in parallel.
Figure 9.7
OR ladder logic diagram
PPM 300 PICUS manual 4189341080 UK
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