Those parameters are used to set up a function called
“Live Zero”.
Parameter 6-00 is the
“Live Zero” timeout time, and 6-01 is the “Live Zero” function. How it works is as follows; if the
analog signal on AI 53 or 54 falls below 50% of the minimum scaling of that input (P6-10 or
P6-20), the drive will start to count down from the time set in P6-00. If the condition still exists
after the timer expires, the function set in parameter 6-01 will be executed.
These
parameters are there to protect you from loosing an analog reference/feedback signal
and running out of control.
Parameters 6-00 & 6-01 are global to both inputs, but you can
enable or disable the function for either input using P6-17 & 6-27.
The parameters in Q3-30 are complete. Next, use the “Back” key to bring you out of Q3-30
and enter Q3-31. Scroll down through the menu and enter the following parameters;
20-81 - Normal
20-83 - 20 Hz or 20-82 to 600 rpm (600 rpm is = to 20 Hz)
Why does it make sense to set parameter 20-83 to at least the same value as parameter 4-12?
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20-21 - 80 PSI (this is our desired system set-point to maintain, between 3-02 & 3-03)
20-93 - 2
(higher numbers result in more aggressive action)
20-94 - 8 seconds
(higher numbers soften response)
The last step in the programming is to set up the LCP display parameters with relevant data.
Using the “Main Menu”, enter the following parameters;
0-20 - Reference Unit
0-21 - Analog Input 54
0-22 - Feedback Unit
Turn pot 1 all the way to the left and leave it there for the rest of the lab. Pot 1 is
connected to AI 53, which is set as the reference input. If it is not turned to the left, it
will add to our desired set-point of 80 PSI.
If you press the “Status” key and view the top line, you should see the set-point of 80 PSI in
the left, the voltage applied to analog input 54 in the middle and the corresponding feedback
in PSI at the right.
Use the potentiometer (pot 2) to change the voltage on AI 54 and watch the feedback
pressure change.
Approximately how many volts on analog input 54 represent a feedback pressure of 50 PSI?
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