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provides a variable time from 1.0 to 20.0 seconds, according to the
value of the potentiometer.
If input values exceed the limits set in the RANGE function, the
output will be blocked to the minimum or maximum allowed value.
As for the output PID, the minimum and maximum values serve to
calculate the value of the output generated by the algorithm of
regulation. Let us consider the following example:
RANGE( PID1, Min 100, Max 500 )
The function imposes the minimum limit of 100 and the maximum
limit of 500 for the PID1 output. This means that an output of 0%
corresponds to the minimum value imposed (100) and 100% will
correspond to an output equal to the maximum value (500).
7.16 NOT contacts
The contact NOT modifies the state of the flow of current. The flow
of current stops if it reaches a NOT contact and supplies energy if
it doesn’t reach it.
The operation NOT inverts the logical value (0
1 and 1
0).
7.17 P and N contacts
The transition positive P contact activates the flow of current for
one scan cycle of each transition from OFF to ON. The transition
negative N contact activates the flow of current for one scan cycle
of each transition from ON to OFF.
The instructions that follow in the diagram are thus executed only
once (per scan cycle) for each transition that activates the contact.
7.18 SEND functions
The function SEND transmits the data through the serial line in
free-port mode.
In this mode, enabled by the special markers SM39, SM40, and
SM41, the protocol that normally manages the serial port is
disabled and the Ladder program takes control of the port and of
the transmission and reception buffers.