Yaskawa Ladder Works Programming Manual - Manual (Page 140)

7.7 FIRST-ORDER LAG Instruction (LAG)
7-19
7.7 FIRST-ORDER LAG Instruction (LAG)
[Outline]
The LAG instruction calculates the first-order lag according to the contents of a previously set
parameter table. The input (Input) to the LAG operation must be integer or real number data.
Double-length integer data cannot be used. The configurations of the parameter tables for integer
and real number data are different. Operations are performed by processing each parameter as an
integer consisting of the lower-place 16 bits.
Table of Integer Type LAG Instruction Parameters
ADR Type Symbol Name Specification I/O
0 W RLY Relay I/O Relay input, relay output *S 1 IN/OUT
1 W T First-order lag time
constant First-order lag time constant(ms) IN
2 W Y LAG output LAG output (also output to the A register) OUT
3 W REM Remainder Storage of remainder OUT
* 1 : Relay I/O Bit Assignment
BIT Symbol Name Specification I/O
0 IRST LAG reset "ON" is input when LAG is reset. IN
1 to 7 － (Reserve) Reserve relay for input IN
8 to F － (Reserve) Reserve relay for output OUT
Table of Real Type LAG Instruction Parameters
ADR Type Symbol Name Specification I/O
0 W RLY Relay I/O Relay input, relay output *S 1 IN/OUT
1 W － (Reserve) Reserve register －
2 F T First-order lag time
constant First-order lag time constant(s) IN
4 F Y LAG output LAG output (also output to the F register) OUT
* 1 : Relay I/O Bit Assignment
BIT Symbol Name Specification I/O
0 IRST LAG reset "ON" is input when LAG is reset. IN
1 to 7 － (Reserve) Reserve relay for input IN
8 to F － (Reserve) Reserve relay for output OUT
Here, the LAG operation is expressed as follows:
Y 1
X
=
1＋T×S
; ie. T× ( dY/dt ) + Y = X
The following operation is performed within the LAG instruction with dt = Ts and dY = Y-Y':
T×Y' + Ts×X + REM
Y =
T + Ts
X : input value
Y : output value
Y' : previous output value
Ts : scan time set value
Y = 0 and REM = 0 are output when the LAG reset (RST) is "ON".