YASKAWA T1000V, Техническое руководство

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5.2 b: Application
YASKAWA ELECTRIC SIEP C710606 44B YASKAWA AC Drive T1000V Technical Manual 121
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■ b4-01, b4-02: Timer Function On-Delay, Off-Delay Time
b4-01 sets the On-delay time for switching the timer output. b4-02 sets the Off-delay time for switching the timer output.
■ Timer Function Operation
When the timer function input closes for longer than the value set in b4-01, the timer output switches on. When the timer
function input is open for longer than the value set in b4-02, the timer output function switches off. The following
diagram demonstrates the timer function operation.
Figure 5.15
Figure 5.15 Timer Operation
◆
b5: PID Control
The drive has a built in PID (Propor In Derivative) controller that can be used for closed loop control of
system variables such as pressure, temperature etc. The difference between the target and the feedback value (deviation)
is fed into the PID controller. The PID controller adjusts the drive output frequency in order to minimize the deviation,
providing an accurate control of the system variables.
■
P Control
The output of P control is the product of the deviation and the P gain so that it follows the deviation directly and linearly.
With P control only an offset between the target and feedback remains.
■
I Control
The output of I control is the integral of the deviation. It minimizes the offset between target and feedback value that
typically remains when pure P control is used. The integral time (I-time) constant determines how fast the offset is
eliminated.
■
D Control
D control predicts the deviation signal by multiplying its derivative (slope of the deviation) with a time constant and
adding this to the PID input. This way the D portion of a PID controller provides a braking action to the controller
response and can reduce the tendency of oscillations and overshoot.
Be aware that D control tends to amplify noise on the deviation signal, which can result in control instability. D control
should therefore only be used when necessary.
■
PID Operation
To better demonstrate how PID works, the diagram below shows how the PID output changes when the PID input
(deviation) jumps from 0 to a constant level.
Figure 5.16
Figure 5.16 PID Operation
No. Name Setting Range Default
b4-01 Timer Function On-Delay Time 0.0 to 300.0 s 0.0 s
b4-02 Timer Function Off-Delay Time 0.0 to 300.0 s 0.0 s
b4-01 b4-02 b4-01 b4-02
Multi-function Contact
Input: Timer Function
On (Closed)
Off (Open)
On (Closed)
Off (Open)
Multi-function Contact
Output: Timer Function
ON ON
ON ON
PID input
I control
PID Output
D control
Time
PID output
Time
P control