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3 Safety Standard Function Blocks
NX-series Safety Control Unit Instructions Reference Manual (Z931)
3
SF_CTD
SF_CTD
This FB decrements the counter value when the counter input signal is received.
• The SF_CTD instruction creates a down counter. The preset value and counter value must have a
SAFEINT data type.
• When load signal
Load
changes to TRUE, counter value
CV
is set to the value of preset value
PV
and counter output
Q
changes to FALSE.
• When counter input signal
CD
changes to TRUE,
CV
is decremented.
• When the value of
CV
reaches 0 or less, the value of
Q
changes to TRUE.
• After the value of
CV
reaches 0 or less,
CV
does not change even if
CD
changes to TRUE.
•
CD
is ignored while
Load
is TRUE.
CV
is not decremented.
Instruction
Name
FB/FUN
Graphic expression
SF_CTD
Down-counter
FB
Variables
Input Variables
Variable
Name
Data type
Valid range
Default
Description
CD
Counter input
BOOL
TRUE or FALSE
FALSE
Counter input
LOAD
Load signal
BOOL
TRUE or FALSE
FALSE
TRUE: Set CV to PV.
PV
Preset value
SAFEINT
0 to 32767
0
Counter preset value
Output Variables
Variable
Name
Data type
Valid range
Default
Description
Q
Counter output
SAFEBOOL TRUE or FALSE
FALSE
TRUE:
CV
is 0 or lower.
FALSE:
CV
is 1 or higher.
CV
Counter value
SAFEINT
0 to 32767
0
Counter present value
Function
SF_CTD
CD
LOAD
PV
Q
CV
Summary of Contents for NX-SL series
Page 8: ...CONTENTS 6 NX series Safety Control Unit Instructions Reference Manual Z931 ...
Page 28: ...Sections in this Manual 26 NX series Safety Control Unit Instructions Reference Manual Z931 ...
Page 98: ...2 Standard Functions 2 64 NX series Safety Control Unit Instructions Reference Manual Z931 ...
Page 104: ...2 Standard Functions 2 70 NX series Safety Control Unit Instructions Reference Manual Z931 ...
Page 110: ...2 Standard Functions 2 76 NX series Safety Control Unit Instructions Reference Manual Z931 ...
Page 265: ...I 1 I NX series Safety Control Unit Instructions Reference Manual Z931 Index ...
Page 268: ...I 4 NX series Safety Control Unit Instructions Reference Manual Z931 Index ...
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