YASKAWA E7U Programming Manual page 26

Industrial hvac drive
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b5-14 PI Feedback Loss Detection Time
Setting Range:
0.0 to 25.0 Seconds
Factory Default: 1.0 Seconds
The Drive interprets feedback loss whenever the feedback signal drops below the value of b5-13 and stays below that level for
at least the time set into b5-14. See Figure below for timing details.
Measured
Feedback
Feedback
Feedback
Loss Output
Loss Digital Output
b5-15 Sleep Function Start Level
Setting Range:
0.0 to 200.0 Hz
Factory Default: 0.0 Hz
b5-16 Sleep Delay Time
Setting Range:
0.0 to 25.5 Seconds
Factory Default: 0.0 Seconds
The Sleep Function can be programmed to prevent running the Drive when the PI loop output or the speed command is so low
that no usable work is being done and/or equipment damage may result. The Sleep Function can be Enabled by entering a
value in parameter b5-15. If the Drive's output drops below the level set by the Sleep Function Start Level (b5-15) and
remains there at least as long as the delay time determined by the Sleep Delay Time (b5-16), then the Drive's internal Run
command drops out and the Drive output ceases. Though the Drive's output has ceased, all other Drive functions continue.
Once the Drive's theoretical output returns to a level above the Sleep Function Start Level (b5-15) and remains above that
level for at least the Sleep Delay Time (b5-16), the internal Run command returns and the Drive output begins again. The
b5-16 Delay Time prevents oscillation about the sleep level.
Note: The sleep function can be used even if the PI function is disabled (b5-01 = "0: Disabled").
Fig. 18 Loss of PI Feedback Feature
t
Outpu
Output
Sleep Level
b5-15
Fig. 19 Sleep Function Response
Programming 20
T
T
Upper Limit
Speed Command
Speed Command
b5-13
T = b5-14
ON (CLOSED)
t
OFF (OPEN)
TIME
d2-01

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