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5.16. Logic Operations
5.16.1. Function blocks
By means of Function Blocks, the Logic Operations function
processes the values of input variables to obtain values for
the output variables.
This lets you control the processes very precisely, because
you can make a number of actions subject to a series of
essential requisites.
The Function Blocks are run every 100msec in sequence,
from FB1 to FB16.
Typical maximum delay from activation of an input and
corresponding output = 100msec.
The Function Blocks are programmed with GF_eXpress
software.
There is a maximum of 16 Function Blocks. Each Block
manages up to 4 input variables and 1 variable output.
Four types of logic operations on input variables a, b, c and
d can be performed on the Function Blocks
• (a AND b) OR (c AND d)
• (a OR c) AND (b OR d)
• a OR b OR c OR d
• a AND b AND c AND d
where the AND operator means that the linked operands
must evaluate to “true” for the result to be “true,” whereas
with the OR operator is it sufficient for only one linked ope-
rand to evaluate to “true” for the result to be “true”.
Parentheses change the order of evaluation of the expres-
sions, i.e., expressions in parentheses are evaluated first,
and the result is then used for expressions outside paren-
theses.
The input variables (a, b, c, d) to each Function Block can
refer to:
• digital inputs (2 or 3 for model 650, 5 for models 1250
and 1350),
• state of alarms,
• state of control output,
• state of controller,
• state of setpoint programmer,
• variables FB_OUT01…16 from other Function Blocks
The result of the Logic Operations function can act on:
• state of controller,
• state of setpoint programmer,
• state of alarms,
• outputs, by directly setting the state.
5.16.2. Groups of variables
The controller provides a large number of variables that can
be used in input for Logic Operations.
The controller has the following groups of homogeneous va-
riables:
State Keys
BUT1
BUT2
BUT3
State of digital inputs
DIGITAL INPUT 1
DIGITAL INPUT 2
DIGITAL INPUT 3
DIGITAL INPUT 4
DIGITAL INPUT 5
State of digital outputs
OUTPUT 1
OUTPUT 2
OUTPUT 3
OUTPUT 4
Function commands
AU-MA (select Automatic / Manual)
LO-RE (select Local / Remote)
HOLD (hold main input variable)
AL ACK (reset alarms latch)
A.TUNE (start Auto-Tuning)
S.TUNE (start Self-Tuning)
ON-OF (software ON-OFF)
SKEY (block F key)
WRI.EN (enable write configuration parameter)
SP.SE.L (select SP1/SP2 or SP1…SP4 low bit)
SP.SE.H (select SP1…SP4 high bit)
T.STST (start/stop timer)
T.RST (reset timer)
P.STST (start/stop programmer)
P.STRT (start programmer)
P.STOP (stop programmer)
P.RST (reset programmer)
P.SKP (skip to end program)
ST.SKP (skip to end step)
ST.ENB.1 (consent 1 to start step)
ST.ENB.2 (consent 2 to start step)
ST.ENB.3 (consent 3 to start step)
ST.ENB.4 (consent 4 to start step)
LED.GREEN.1 (only for 1350 model)
LED.GREEN.2 (only for 1350 model)
LED.GREEN.3 (only for 1350 model)
LED.GREEN.4 (only for 1350 model)
LED.GREEN.5 (only for 1350 model)
LED.GREEN.6 (only for 1350 model)
LED.GREEN.7 (only for 1350 model)
LED.GREEN.8 (only for 1350 model)
LED.RED.1 (only for 1350 model)
LED.RED.2 (only for 1350 model)
LED.RED.3 (only for 1350 model)
LED.RED.4 (only for 1350 model)
LED.RED.5 (only for 1350 model)
LED.RED.6 (only for 1350 model)
LED.RED.7 (only for 1350 model)
LED.RED.8 (only for 1350 model)
LED.OUT.1
LED.OUT.2
LED.OUT.3
LED.OUT.4
Function state
PID heating
PID cooling
PID zero
ON/OFF heating
ON/OFF cooling
ON/OFF zero
OR state active alarms)
AL1…AL4 (Alarm AL1…4 state)
LBA ALARM (LBA alarm state)
HB ALARM (HB alarm state)
5. Examples and applicative notes
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