Delta Electronics DVP15MC11T - Page 120

Chapter 8 Logic Instructions
8_

Programming Example

The variable table and program
Variable name Data type Initial value
CTD1
CTD
CTD1_EN
BOOL
FALSE
CTD1_CD
BOOL
FALSE
CTD1_Load
BOOL
FALSE
CTD1_PV
UDINT
4
CTD1_Q
BOOL
CTD1_CV
UDINT

Timing Chart:
Case 1： There is no impact on the ouput by triggering CTD1_CD when the value of CTD1_CV is
0.
Case 2： When CTD1_Load is TRUE and CTD1_CV equals the set value of CTD1_PV, CTD1_Q
changes from TRUE to FALSE. At the moment, CTD1_CV does not count down when
CTD1_CD is triggered.
Case 3： If CTD counts down normally and CTD1_Load is FALSE, the value of CTD1_CV is
decreased by 1 whenever CTD1_CD is triggered once. CTD1_Q is TRUE when the
value of CTD1_CV is decreased to 0.
1
CTD
EN ENO
Q
CTD1
CD
Q
Load
CV
PV
CTD1_EN
CTD1_CD
CTD1_Load
CTD1_PV
CTD1_ Q
CTD1_ CV
CTD1_CD
CTD1_Load
CTD1_Q
CTD1_CV
CTD1_PV
Case 1 Case 2 Case 3
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