Issue
102 January 1999
The
PCL3013 Step/Servo Motor Controller in Action
by
Gordon Dick
If
you need a high-performance step/servo motor controller,
check in with Gordon. Along with its unique approach
to program memory (data is written to preregisters),
the PCL3013 offers so many interesting features, you
won’t want to miss out.
It’s
getting harder and harder for the average person to
mess around with stuff! Most folks won’t build
a PC board just to test this new micro or that new controller
if the device is only available in a surface-mount package.
Oh
sure, evaluation boards are available, but that changes
a $10 ding in the wallet into a $100 dent. And even
if you go to the trouble of building a PCB, it takes
some skill to solder a surface-mount device by hand.
The day is approaching when, unless it’s part of
your job, you won’t be able to tinker with whatever
device is currently new and hot.
The
PCL3013 is a high-performance step/servo motor controller
with an exciting array of features and it was a newly
introduced device when I began this project about a
year ago. Like most step/servo motor controllers, it’s
intended to be used with a host micro directing its
operations. It keeps track of the time-critical items
and does any required calculations, freeing up the host
to do other things.
The
PCL3013 features control of step motors or pulse input
servo motors, linear or S-curve acceleration, microstepping,
stepping rates up to 4.9 Mpps, and out-of-step detection.
It also offers a Motorola or Intel interface, an 8-
or 16-bit data bus, 12 different origin returns, and
interrupts that signal various internal events. With
all of these features, it’s no surprise that this
device has a large number of pins, as illustrated in
Figure 1.
Solutions
to many problems I previously encountered seemed to
be at hand with this device. Let’s see how it
addresses them.
DOING
IT RIGHT
First
off, let’s say I have this device—thanks to
the folks at Kollmorgen for the samples—that I’m
anxious to get working. Should I try to haywire it together?
Or,
maybe there’s an adapter unit out there, something
that lets me solder my device to it and then have wire-wrap
pins to work with. Such adapters are available for a
variety of surface-mount styles, but not this one because
of the lead spacing. The lead spacing of this device
is metric because it is made by Nippon Pulse, a Japanese
device manufacturer.
I
care how it looks and it’ll probably save me time
in the long run to do it right the first time, so I
opted to make an adapter. That turns out to be more
work than I thought. (How many times have I jumped into
a project and said that?)
MADE
A PCB LATELY?
Like
everyone in the industry, we threw out our tape and
donut supply quite a while back. All our PCBs are made
using a CAD PCB design package.
When
I complained to one of my colleagues about how easy
it was to make a PCB in the good old days and how hard
it is now (since I don’t use powerful PCB CAD packages
that often), he told me about EasyTrax. It’s available
for free on the ’Net and it’s easy to learn.
In about three or four hours, I was done with the tutorial
and in another three or four hours, I had my adapter
layout complete.
For
many of the PCBs we make, there is no longer any photography
involved. A negative is made in a laser printer on a
transparency. Once I have the negative, it isn’t
long before I have a decent-looking adapter board waiting
for a device, pull-up resistors, and wire-wrap pins
to be installed.
How
often do you solder a surface mount IC to a PCB? I don’t
do it often. Examining my first attempt under a microscope
reveals it’s not perfect. A few leads may not be
connected.
After
a touchup or two and a vigorous wash in alcohol, it
looks all right. The pull-up SIPs and the wire-wrap
pins can now be installed. I’m getting close to
wiring!
