Siemens Logo! Manual page 237

3. As AQ is set to 0 by means of the input R, PV changes.
This is based on the fact that PV increases, which on
account of Dir = upwards causes AQ to drop.
Functional description
If the input A/M is set to 0, then the special function issues
output AQ with the value that you set with parameter Mq.
If the input A/M is set to 1, then automatic mode
commences. As an integral sum the value Mq is adopted,
the controller function begins the calculations.
Note
For further information on the controller basics please refer
to the Online Help for LOGO!Soft Comfort.
The updated value PV is used to calculate in the formulas:
S
If the updated value PV = SP, then the special function
does not change the value of AQ.
S
Dir = upwards (+) (timing diagram numbers 1. and 3.)
– If the updated value PV > SP, then the special
– If the updated value PV < SP, then the special
S
Dir = downwards (–) (timing diagram number 2.)
– If the updated value PV > SP, then the special
– If the updated value PV < SP, then the special
With a disturbance, AQ continues to increase / decrease
until the updated value PV again corresponds to SP. The
speed with which AQ changes depends on the parameters
KC and TI.
LOGO! Manual
A5E00380835-01
Updated value PV = (PV
gain) + offset
function reduces the value of AQ.
function increases the value of AQ.
function increases the value of AQ.
function reduces the value of AQ.
LOGO! functions
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