Testing the Parker MX80L

It's time to discover whether the components I have purchased are functional.  I'm not capable of repairing any problems with an MX80L, and replacement parts are likely to cost more than simply purchasing another stage.  Let's hope luck is on our side and get started.

Given that the MX80L is plug and play, this post is really about setting up the Parker VIX IH drives.  As purchased, the VIX IH drives came with a full complement of cables.  This is kind of nice since I can cut a few of them up for testing.  I put them aside and got the drives ready.

The Parker VIX IH is a pretty high end servo drive and must be configured over serial communication using software they provide.  The first step is to wire up a cable so that it can communicate with a computer.  They provide a handy wiring guide to make it easy.

A touch of solder and heatshrink, and we have our cable.

Next we connect it to a computer and hope it communicates.

All three servo drives respond to a STATUS request and otherwise appear functional.

Since everything is looking good so far, its time to start the configuration.  You are given a basic GUI interface to select the motor type, gains and other miscellaneous choices.  As the MX80L is made by Parker you can simply select it from the list and click through.

At the end of the process you are prompted to upload the configuration to the drive.

If you aren't paying attention it is very easy to miss, but there is actually a huge twist here - the configuration was not directly uploaded to the drive!  Instead, a 80 lines of code were generated, uploaded to the drive, and executed.  The generated program configures the drive, sets up a fault handling event, and then loops in a "move" subroutine that runs the motor backwards and forwards.

The difference may seem insignificant, but this tells us something fairly critical: Doing anything with the VIX requires writing programs of reasonable complexity.  In fact there is no configuration option for step/dir input - we are going to have to program that ourselves!  The majority of the 250 page manual describes the "EASI" programming language, complete with subroutines, loops, conditional statements, and much more.  The drive itself has a selection of input and output pins, and the whole experience feels a lot like programming the 1990s equivalent of an Arduino.

This unexpected in a servo drive and would probably scare most non-programmers away.  It does, however, provide some extremely powerful options if you are willing to take advantage of them.

After configuring the drive I can finally connect the servo.  This is a breeze since the connectors are compatible.

Finally we type 1GOTO(START) into the terminal to run our program and actuate the stage.  I am powering everything using my benchtop supply which only goes to 30V.  The components are designed to be run on 80V so this will somewhat limit performance.

The stage works perfectly, although when limited to 30mm/s its not that impressive to look at.  You can monitor the maximum error of the stage and even when applying reasonable force to the table it never deviates more than 1 micron from the set point.

I repeated the same process with the second MX80L stage and the remaining two VIX IH drives to confirm that everything works.  The second MX80L has a broken home switch but is otherwise in good shape.  The lack of a home switch is not a big deal as it is superseded by the more accurate encoder Z channel.

This was fun, but everything pretty much worked as expected.  Getting the Aerotech to move will be a much greater challenge and the topic of my next post.