Rockwell Automation T8019 Trusted Process Control Algorithm Software Package - Manual (Page 10)

Trusted
TM
Process Control Algorithms T8019
Issue 8 Sep 07 PD-T8019 10
1.3. Analogue Select
R_SEL
PV1
OUT
PV2
SEL
The process variables (PV1 and PV2) and the output (OUT) must all be of type REAL 1 . The select
signal (SEL) is of type BOOLEAN. When SEL is FALSE, PV1 is copied to the output; when SEL is
TRUE, PV2 is copied to the output.
if SEL
Set OUT = PV2
else
Set OUT = PV1
end if
Out is finite if, and only if, the selected PV1 or PV2 is finite.
1.4. Multiple Value Averaging
AVG
N
OUT
PV1
PV2
PV3
PV4
PV5
PV6
PV7
PV8
PV9
PV10
The multiple value averaging calculates the average of between 1 and 10 values (PV1 to PV10). N
specifies the number of values averaged; the first N values are averaged. E.g. if N=3, the average of
PV1, PV2 and PV3 is returned. N is of type INTEGER, PV1 to PV10 and OUT are of type REAL. All
input values must be connected; unused inputs should be tied to either one of the other used inputs or
a constant value.
If the value of N is out of range, i.e. 1>N>10, the average of all ten input values is to be returned and
the “param” error count incremented. Overflow errors occurring whilst calculating the average are to
result in a value of PV1 being returned and the “overflow” error count incremented. If an “underflow”
condition occurs, the function is to set OUT to zero and increment the “underflow” error counter.
1 The standard ISaGRAF SEL function provides the equivalent operation for integer values.