Function Blocks
Function Block Reference Guide
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2.76 UPDN Function Block,
continued
Block Properties
Double click on the function block to access the
function block properties dialog box.
Block Order (Read Only)
You can change the assigned execution order
number by selecting “Execution Order” in the
“Configure” menu and arrange the order to suit
your control strategy.
Configuration Parameters
You must configure the UPDN function Block
parameters to the desired value or selection that
matches your operating requirements.
Table 2-65 describes the parameters and the
value or selection.
Table 2-65 UP/DOWN Configuration Parameters
Properties Group
Parameter
Index#
Parameter Description
Value or Selection
Presets
Local Preset
0
Local Preset
1 to 99999
1
On selects remote preset
Click on Box to select
Example
Figure 2-80 shows a Function Block Diagram using a UPDN function block. This example uses a Totalizer function block as a
retentive timer. If a fixed input of 1 is provided to the block using a Numeric Constant, the totalizer will time up to 1 at the input
rate selected (per sec, per min., per hr, or per day). For example, if the “per hr” rate were selected, the output would be 1.0 after
1 hour, 2.0 after 2 hours, etc, up to the Preset value.
A counter is shown to count the number of pump cycles (On to OFF transitions).
The P4-RESET Digital Variable is used to reset the timer and counter
Figure 2-80
UPDN Function Block Example