iDect FC6A series, User Manual

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FC6A S
ERIES
M
ICRO
S
MART
A
LL
-
IN
-O
NE
T
YPE
U
SER
’
S
M
ANUAL
FC9Y-B1722 5-53
5: F
UNCTIONS AND
S
ETTINGS
Constant Scan Time
The scan time may vary whether basic and advanced instructions are executed or not depending on input conditions to these
instructions. The scan time can be made constant by entering a required scan time preset value into special data register D8022
reserved for constant scan time. When performing accurate repetitive control, make the scan time constant using this function.
The constant scan time preset value can be between 1 to 1,000 ms.
The scan time error is ±1 ms of the preset value normally. When the data link or other communication functions are used, the scan
time error may be increased to several milliseconds.
When the actual scan time is longer than the scan time preset value, the scan time cannot be reduced to the constant value.
Special Data Registers for Scan Time
In addition to D8022, three more special data registers are reserved to indicate current, maximum, and minimum scan time
values.
Note: R/W is the abbreviation for read/write. When R/W, it can be read and written. When R, it can only be read. When W, it can only be written.
Example: Constant Scan Time
This example sets the scan time to a constant value of 500 ms.
D8022 Constant Scan Time Preset Value (1 to 1,000 ms)
D8023 Scan Time Current Value (ms)
D8024 Scan Time Maximum Value (ms)
D8025 Scan Time Minimum Value (ms)
M8120 is the initialize pulse special internal relay.
When the FC6A Series MicroSmart starts operation, the MOV (move) instruction stores
500 to special data register D8022.
The scan time is set to a constant value of 500 ms.
M8120
REP D1
500
S2
D8022
MOV(W)