Down Counter - Mitsubishi Electric MELSEC-Q/L Programming Manual

Down counter

CTD(_E)
High
Basic Process
Redundant Universal
performance
Structured ladder/FBD
CTD_E
EN ENO
s1 d1
s2 d2
n
The following function(s) can go in the dotted squares.
CTD, CTD_E
■Argument
Input/output Name
argument
Input argument EN
s1(CD)
s2(LOAD)
n(PV)
Output argument ENO
d1(Q)
d2(CV)
Processing details
■Operation processing
• Counts down (-1) (d2) when (s1) is turned ON. n sets the initial value for subtraction. (d1) turns ON when count value (d2)
reaches 0. When (s2) is turned ON, (d1) turns OFF and initial value for subtraction n is set for count value (d2).
• Valid setting range for n is -32768 to 32767. However, if 0 or less is set, (d1) is turned on regardless of the count value of
(d2).
■Operation result
• Function without EN/ENO
An operation is executed and the operation value is output from (d1) and (d2).
[Timing chart]
When n=3
ON ON
s1
OFF OFF OFF
ON
s2
OFF OFF
ON
d1
OFF
d2
0 3
Initializes d2 when s2 = ON. Counts
LCPU
ST
(EN, s1, s2, n, ENO, d1, d2);
CTD_E
Description
Executing condition (TRUE: Execution, FALSE:
Stop)
Count signal input
Count reset
Count start value
Execution result (TRUE: Normal, FALSE: Error or
stop)
Count match output
Count value
ON ON ON
OFF OFF
ON
2 1 0
d2 down at the falling of s1 .
Data type
Bit
Bit
Bit
Word (signed)
Bit
Bit
Word (signed)
ON ON ON
OFF OFF OFF
ON
OFF
OFF
3 2
5.11 Standard Counter Function Blocks
OFF
1
5 APPLICATION FUNCTIONS
5
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