Figure 9.9
NAND ladder logic diagram
Table 9.10
NAND logic truth table
B0
B1
B2
FALSE
FALSE
TRUE
FALSE
TRUE
TRUE
TRUE
FALSE
TRUE
TRUE
TRUE
FALSE
NAND example
When two warnings are present, the generator breaker is opened.
NOR
Two normally closed contacts connected in series. This operation is the opposite of the OR operation. The output of a
normally open coil is TRUE, until the input of one or both normally closed contacts are TRUE.
Figure 9.10
NOR ladder logic diagram
Table 9.11
NOR logic truth table
B0
B1
B2
FALSE
FALSE
TRUE
FALSE
TRUE
FALSE
TRUE
FALSE
FALSE
TRUE
TRUE
FALSE
NOR example
A ready light is activated until warning A and/or warning B is activated.
PPM 300 PICUS manual 4189341080 UK
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