Suppose you have a conveyor oven where one shift has a product that requires a certain
amount of time in the oven, but the next shift a different product is being baked and requires
a different time.
And the next shift another product which requires yet another time.
You COULD use the GSD8 DC Drive in Rate mode, but that means you would have to calculate
all the various shaft rotation speeds to give you the time in the oven each product requires.
And when you get as new product, you have to do it all over again.
Yuck.
Or, you could use Time mode.
In Time mode, you just tell the drive how much time you want a product to be in the
oven.
And it’s super easy to do.
You just do a onetime measurement and the GSD8 DC Drive will automatically calculate
any future shaft speeds you may need.
So all you have to do is just enter the time you want the product to be in the oven or
whatever timed process you have!
This mode will save you a lot of headaches and frustration.
Let’s do an example.
Suppose we have a conveyor oven, and we used the DC Drive to control the motor in Rate
mode and we found that at a shaft speed of 1380 RPM it takes 6 minutes and 40 seconds for
the product to get through the oven tunnel.
And suppose we want to prevent the user from entering an inappropriate time, so let’s
say we want to limit the display entry to something between 6 minutes and 30 seconds
and 12 minutes and 15 seconds.
Let’s also give the user the option to expedite things through the oven by switching to a
fixed JOG oven duration of 2 minutes.
Ok, well we only have to do two things.
We need to enter the measured data point and configure the display.
Here are the steps to do this.
Let’s take them one at a time.
Before we get started, let’s do a factory reset so we are all starting from the same
place.
Drop into Parameter mode, scroll to parameter 95 and enter a 5.
Up arrow to confirm.
By the way, I should point out that all the parameter numbers we’re using in this demo
work for both the 10-amp and 5-amp drives.
The two drives don’t always share the same parameter numbers, but the parameter numbers
we are using in this demo happen to be the same.
So I’ll mark that here as a reminder.
I’m using the same demo hardware as the previous video, so I’m not going to dwell
on that here.
The key thing to note is I’m using the GSD8-PU2E encoder with the 20 pulses per revolution
disc installed.
You can use any sensor you want as long as it generates a digital pulse stream from 5
to 24 volts.
So, we just need to make sure the drive knows we are using a 20 PPR sensor.
Drop into parameter mode, scroll to parameter 32 and we see the default for this drive happens
to be 20 PPR so we are good to go.
We need to put the drive into Time mode.
Scroll to parameter 10.
Press enter and change it to a 2 for Time mode.
Enter to accept.
We measured our reference oven duration to be 6 minutes and 40 seconds at a motor speed
of 1380 RPM.
The time goes in parameter 30 and
6 minutes and 40 seconds is 400 seconds.
Move up to parameter 31 and enter the RPM we measured.
Great!
Given that the GSD8 Drive will now be able to calculate the motor RPM for any time we
enter.
We want to limit the user to a min and max time, so we go to parameter 20 and we enter
the min time in seconds and go to parameter 21 and enter the max time in seconds.
We wired terminal S2 as our JOG function, so we need to go to parameter 35 and change
it to a 7 to tell the drive we did that – which happens to be the default for this drive,
so we are good to go.
And we need to go to parameter 36 and enter the expedited oven time of 2 minutes – or
120 seconds.
Well, that’s it for entering parameters, so I’ll scroll to parameter 0 and BEFORE
I hit enter, I’m going to enable the INHIBIT so we don’t get any surprises.
And now I’ll hit enter to exit parameter entry mode.
This is REALLY important … whenever you change the mode of the drive, you have to
power cycle the drive for the mode change to take effect.
While the drive is off, we don’t want anyone changing this setup, so let’s open the drive
case and move JP1 to the OFF position.
That prevents anyone from making programming changes.
Ok, let’s apply power to the drive!
If I flip the inhibit switch on, then the drive automatically goes to the minimum time
we set – 6 minutes and 30 seconds.
That’s really important – the drive didn't start at zero because we told it not to with
the min time setting.
So, if you want to avoid surprises, it’s important to have the inhibit switch
enabled when you start things up.
Out of curiosity, I wonder how many RPMs that is.
The 6 minutes and 30-second min should be a little higher RPM than the 1380 RPM we
measured for 6 minutes and 40 seconds – right?
Sure enough, it is.
Notice that the user can’t go below 6:30 because that was the lower limit we entered.
If I scroll up, sure enough it stops at the upper limit we set.
And out of curiosity, I wonder what RPM that is.
It’s a longer duration in the oven, so it should be a lot slower RPM, right?
And … it is.
But how cool is it that we didn’t have to figure that out?
The drive did it for us automatically.
I love this feature.
Finally we set JOG to expedite the conveyor through the oven in only two minutes – so
that should be a lot faster RPM – right?
And sure enough it is.
And notice that JOG is NOT limited by the min/max durations we entered – 2 minutes
is a LOT faster than the 6 minutes 30-second limit we entered, isn’t it?
That ought to get you up and running with the Time mode in the GSD8 Digital DC Drive
from AutomationDirect.
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