Welcome Back.
In the Quick Start video, we walked through setting up the SureStep system and used Self
Test to check everything out.
In this video, we’ll take a closer look at all the features of the SureStep software
so you can get the most out of your stepper system.
Keep in mind that this is only for the Advanced Stepper Drives that use the SureStep software
– not the drives that use dip switch settings.
Let’s start with the drive selection.
. Currently there are two drives that are configurable via this software.
Select the one you will be using.
This is the rev of the current drive.
It gets updated when you first turn the drive on – I’ll reach over and turn the drive
on here.. there it is – or anytime you do something that reads from the drive, like
an upload or status monitor.
That’s a really good number to have handy when you call into Tech Support.
Click here to select the how your controller will talk to the motor.
You can use pulse and direction – this is where one input is the pulses for movement
– the faster the pulses the faster the movement - and the other input indicates direction.
You can also send pulses in one input for one direction and pulses in the other input
for the other direction.
And you can use quadrature inputs.
If the A pulse goes active before the B pulse the motor turns one direction, if the B pulse
rises first the motor turns the other direction.
This option is cool because it let’s you control the drive directly from an incremental
quadrature encoder that is being driven from some other part of the system.
You can specify how many steps per revolution here.
The higher the number, the smoother the motor operates.
Now, if you choose a high number, just make sure your controller can handle it at the
rat you want to rotate the motor.
You can specify anything from 200 to 51,000 steps per revolution with these drives.
You can add a smoothing filter to help reduce noise.
This is the corner frequency of that low pass smoothing filter.
Beware, because this is a low pass filter it WILL delay the output.
The lower the cutoff frequency, the longer the delay.
Here is an example from the help file – it shows that changing the filter from 1000 Hz
to 50 Hz adds a 45 millisecond delay … so just beware of that …
You can also filter the digital inputs.
This can be helpful if your digital lines have noise on them.
Now keep in mind that if you lower the frequency response using this to say 200 KHz, then any
pulses you send faster than that won’t make it past the filter.
Which means you are ultimately limiting the speed of the motor.
For example, suppose we set the filter to 200 KHz and the drive is setup for 20000 pulses
per revolution.
Since this is now our maximum pulse rate, we have limited our maximum motor speed to
10 rev/sec or 600 rpm.
You could either increase the filter limit OR lower the pulses pre revolution.
Of course, that would increase your step size … it’s always a trade off – isn’t
it?
The cool thing about these advanced drives though, is you have these options to play
with to optimize your system the way you want it.
You can use the input pin to enable the motor or clear alarms and you can use the output
pin to signal fault, braking, motor status or even a tachometer output so you can monitor
the actual pulse rate coming out of the drive.
In the velocity mode you can tell the stepper to turn at a fixed rate with a fixed acceleration
and deceleration and use the Step input as an enable.
The Direction pin controls the direction of rotation.
Or you can use the analog input to control the speed of the motor.
The voltage range is fixed at 0 to 5 volts because that’s what the analog input is
rated for.
You specify what the 5 volt speed is.
So 0 to 5 volts controls the speed and the Direction pin still controls the direction
of rotation.
What if you want the analog input to control the direction?
Maybe have zero be full reverse and 5 be full forward?
Can you do that?
Sure!
Click on the advanced button and put an offset voltage here.
Anything below the offset will turn the motor in reverse.
The farther the analog voltage gets from this offset the faster the motor goes with the
max speed at both ends being this number here.
Or the easiest way is to use this Auto Offset feature.
I have a joystick connected right now and it’s centered.
I just hit the auto offset to record that voltage and now the velocity mode will use
that joysticks center position as the zero speed reference.
You can also setup a dead band so the joystick doesn’t respond for the first few millivolts
and you can filter the analog input to help reduce noise.
The SCL control mode allows you to control the drive via ASCII serial commands.
Using this, you can actually control the Drive from any controller with an RS232 output.
The SureStep Pro software provides a convenient terminal right here.
I like to use that for testing because I can quickly try things before writing my PLC code.
You can set the acceleration, the deceleration, the speed, set the number of pulses to issue,
tell it to go and stop, get status, reset alarms – pretty much everything you could
want to do with a stepper motor, all from this terminal window.
We’ll need another whole video to cover that topic so for now I’ll just point you
to the SCL manual which you can get to from the sure step product page right here.
It’s real easy to read and even has a getting started section that gets you up and running
quickly.
Click here to select the motor.
All of AutomationDirect’s motors are shown here - we’re using this 17060 stepper motor.
That automatically fills in the motor specs and max current for us!
Click here to see all the motor specs.
Even though this max current number was filled in for us, you can still change it.
Suppose you have an oversized motor.
You could reduce the max current to help lower power consumption and reduce the heat generated
by the motor.
You can also setup your own custom motor where you fill in all of those numbers yourself.
We’ll stick with the 17060 motor we have in this demo.
The idle current is the current you want the motor to fall back to when it is not moving.
This is a great way to save power both in the drive and in the motor BUT you sacrifice
holding torque.
So if you need lots of holding torque crank this up.
If you don’t then make it as small as you can.
In general, this 50% number is a great place to start.
This Idle Current Delay is how long the drive should wait before reducing the idle current.
It’s usually a good idea to have a little time here to let the motor settle before reducing
the current.
Finally you specify the load inertia here.
These advanced drives do a really good job of reducing system resonance but that’s
only if you specify an accurate inertia here.
Where do you get the inertia value from?
The SureStep user manual shows you how to calculate it in Appendix C and the videos
on how to choose a stepper motor walks you through step by step how to figure out what
your system’s inertia is.
There’s also a free tool on the AutomationDirect website that you can use to calculate the
system inertia.
Of course you could always do it via trial and error too … this SureStep software makes
it super easy to change so you can try as many times as you want.
I really like that this dialog lets me choose the units I want to work in.
You can also specify the inertia relative to the motors rotor inertia from zero to 20X.
I haven’t done the inertia calculations yet, so I’ll just leave this the default
1X– we can always change this later.
You can disable the damping or anti-resonance by checking this box.
This is great for optimizing your system.
You can try different inertia values and then quickly enable and disable the anti-resonance
feature to see how it affects your system.
And you can turn waveform smoothing on or off.
Normally you will want this on but you can turn it off if you want to see the difference
in how your system reacts.
Ok, the motor is good.
We’ve covered a lot of stuff here, but really all we did was select a drive, choose the
motion type and select a motor.
Now we just download to the drive ad we are good to go.
If I move the analog joystick the motor moves.
First one direction, then the other.
Exactly what we expect because we used that offset option.
Perfect Under this drive menu you can view the alarm
history – here are all the alarm types with column 1 being the most recent alarm.
This is cool because even if you have cleared an alarm, you can still go back and see what
the last 8 alarm conditions were.
Of course you can clear the history here.
This is where you clear the current alarm.
Keep in mind, if you clear an alarm that was found during power up, you won’t get another
one until you power cycle the drive.
You can restore the factory defaults here.
Here’s that terminal we talked about earlier so you can send SCL commands – if you are
in SCL mode of course.
Again, check out the SCL manual for more on that.
Self test is awesome.
We saw that in the quick start.
You just wire up your system, select your motor and drive and then hit self-test.
And if the motor runs back and forth like this, then you know your system is setup and
wired correctly so now you can focus on the configuration.
That saves so much system debug time.
With the system status monitor, you can see at a glance what everything in the drive is
doing in real time.
You can see activity on the inputs – we’re using the analog input right now so we don’t
see anything here.
But if you were using pulse and direction for example, you would see these little LEDs
light up.
If I move that joystick, sure enough you can see the analog input change and the drive
speed change.
Over here, you can see exactly what the drive thinks it is doing and if the alarm is set,
what is causing that alarm.
Over here, you can manually toggle the output pin and down here you can manually enable
and disable the drive.
This little dialog makes debugging stepper systems a breeze.
If you have any questions about AutomationDirect’s stepper drives, please contact our free award
winning tech support during regular business hours.
They will be happy to help.
And don’t forget the forums.
There are lots of folks there that love to share their years of experience.
Just don’t post any questions directed at AutomationDirect’s support team there – they
don’t monitor the forums on a regular basis.