Aritech FP2000, Reference Manual

Page: 147 / 209

Logic
(INPUT/OUTPUT, 3, )
LOGIC TABLE
599
600
1
( Input 1
2 )= Output 1
3 ( Input 2
0. .9, ^V, <>, E, X
Alarms: 0 Faults: 0 Cond.: 0 P: 1 SDZ
Return to Input/Output Menu Page 109
Place cursor over field to be changed and press (Unlock memory!)
Either: Select the function and press
or: 0..9 or select a number and press
Logic sets outputs assigned in the Output Table true or false according to expressions.
An expression in general will contain inputs, outputs, markers and timers connected by
Boolean operators.
All expressions in the logic table are evaluated once per second and the true/false state
is transferred to the assigned output, marker or timer. Logic is the link between the inputs
defined in the Input Table and the outputs defined in the Output Table.
The simplest logic statement requires two steps in the logic table. More complex
expressions require more steps depending on the number of terms in the expression. The
maximum size of the logic table (default 300 steps) can be set in Memory Allocation 1
(
see Page 33) . The logic table entered by the user should have an END statement as the
last step. The END statement terminates evaluation of the table at that point. Any
statements after the END statement will never be evaluated.
The logic steps are evaluated sequentially from step 1 to the END step. This means that
outputs, markers or timers set in previous steps may be used as part of expressions in
later steps. The true/false value used will be the state that exists at the time of evaluating
the expression.
The physical outputs are only set at the END of the table. Thus if an
output is set at the beginning of the table, and then reset later in the table, no physical
output will occur.
The logic table menu contains limited editing features. An INSERT and DELETE function
is provided and NULL statements are allowed. The user is advised to make use of the
FPCONF Download Program to construct lengthy logic tables. A default logic table linking
inputs to outputs can be used.
(See Set Default, Page 65) . Thus simple I/O operations
can be performed without any logic programming. The default mode is described below.
The general form of a logic statement is:
field 1 field 2 field 3 field 4 field 5
Step m ( Term xx
Step m+1 Operator Term xx
| | |
| | |
Step m+n )= Assignment xx yy