YASKAWA Varispeed E7 Instruction Manual And Parameter Description page 229

Square Root Feedback Operation
If parameter b5-28 is set to 1 the feedback value is converted into a value that equals the square root of the
actual feedback. This can be used to control the flow rate when a pressure sensor is used to generate a feed-
back value. With parameter b5-29 the square root can be multiplied with a factor. Following formula applies:
So linear connection between the PI target value and the feedback can be realized.
With parameter b5-30 also the feedback monitor can be switched to show a square root value of the actual
feedback.
Multifunction Digital Input Settings: H1-01 to H1-05 (Terminal S3 bis S7)
PI Control Disable: "19"
When a multifunction input is set for this function it can be used to disable the PI function by switching the
•
input to ON.
The PI target value becomes the frequency reference value.
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PI Control Integral Reset: "30"
Using this function the integral share value of the PI control can be reset by setting a multifunction input to
•
ON.
PI Control Integral Hold: "31"
Using this function the integral share value of the PI control can be hold by setting a multifunction input to
•
ON. The value will be hold as long as the input is ON.
PI Softstarter: "34"
Using this function the PI target value can be raised or lowered slowly using an accel./decel. ramp
•
function. The accel./decel. time can be set in constant b5-17. The function is active when the multi-
function input with this function is ON.
PI Input Characteristic Switch: "35"
Using this function the PI input characteristic can be inverted by setting a multifunction input to ON.
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flow rate = gain (b5-29) x √pressure (head)