Breaking News
Blog

The Art of Test, Part 1: Boards, Subassemblies, & Products

NO RATINGS
View Comments: Threaded | Newest First | Oldest First
MeasurementBlues
User Rank
Blogger
Test fixtures
MeasurementBlues   2/4/2014 5:59:41 PM
NO RATINGS
The closest I came to designing uC based fixtures was with an 8085. We used it to exercise stepper motors. The program would rampt the motor up and down in speed to emulate how the motor would be used in real life.

MeasurementBlues
User Rank
Blogger
No MCU needed
MeasurementBlues   2/4/2014 6:03:25 PM
NO RATINGS
I also designed some fixtures that used a simple ROM. We had the mechancial arm that ran on a motor, back and forth. The arm would reach then end and a sensor would detect it and clock a counter that would send the ROM to the next step, reversing the motor. At the other end the same thing occurred and the arm just went back and forth. The ROM would power up into a state that sent the motor to a known positon and the counter would wait for a pulse from the position sensor.

antedeluvian
User Rank
Blogger
Re: No MCU needed
antedeluvian   2/4/2014 6:29:53 PM
NO RATINGS
Martin

I also designed some fixtures that used a simple ROM. We had the mechancial arm that ran on a motor, back and forth. The arm would reach then end and a sensor would detect it and clock a counter that would send the ROM to the next step, reversing the motor. At the other end the same thing occurred and the arm just went back and forth. The ROM would power up into a state that sent the motor to a known positon and the counter would wait for a pulse from the position sensor.


This sounda like it would have been an ideal application for Mororola's MC14500 single bit (4 bit instructiion set) micro. It also needed external counters and an EPROM. But it could have done your decision making.

Your arrangement sounds rather like a state manchine implemented with a ROM intead of the PLD. At one point the generic development tools like CUPL actually supported PLDS implemented with (E)(P)ROMs. I know I designed one product like that.

MeasurementBlues
User Rank
Blogger
Re: No MCU needed
MeasurementBlues   2/4/2014 7:59:57 PM
NO RATINGS
antedeluvian, Yes it was a simple stat machine, a 4-bit counter driving a ROM. I think it maybe 5-6 counts after eacy cycle, a sensor wouldclear the counter and the repeasted. Simple but effective. The mechanica techs in the lab though it was cool waht we electrical guys did.

I have a story about the tech, but it needs a video. Maybe in the next few days. Tomorrow I'll be shoveling snow in between comments.

MeasurementBlues
User Rank
Blogger
Re: No MCU needed
MeasurementBlues   2/4/2014 10:50:41 PM
NO RATINGS
antedeluvian, here's the video I promised below.

 

 


antedeluvian
User Rank
Blogger
Re: No MCU needed
antedeluvian   2/5/2014 9:14:54 AM
NO RATINGS
Martin

Great video. I must admit it is the first time I have seen video comment. I normally struggle to insert even a jpg file.

MeasurementBlues
User Rank
Blogger
Re: No MCU needed
MeasurementBlues   2/5/2014 10:34:17 AM
NO RATINGS
Aubrey, I tried using the Video Comment link but it didn't work. The video uploaded but EET said the video was not avaialble. So, I uploaded it to my YouTube Channel and used the embedding code, but first I had to resize the video to fit.

If you need help with posting photos etc. search for "How to Use the New EE Times."

krisranes
User Rank
Rookie
Testing Boards
krisranes   2/5/2014 2:38:45 PM
NO RATINGS
Can you tell me where to get the Yellow and white board hold downs from I can not seem to find them

Thanks

Kris Ranes

antedeluvian
User Rank
Blogger
Re: Testing Boards
antedeluvian   2/5/2014 2:58:34 PM
NO RATINGS
krisranes

Can you tell me where to get the Yellow and white board hold downs from I can not seem to find them

 

 

 

The name on the latches is "hua rong" and it has a logo of a spring loaded test probe of the type you see on the jig to make the elcetrical connections. A quick google search seems to show these guys as the likley candidate, (http://www.hrfnet.com/). I have tried working through the site and haven't had much joy. If you contact me at akagan at emphatec dot com I will give you the name of the compnay that makes our jigs. They do sell the latch on its own.

P.S. we are in the process of moving our location and the internet access is very iffy. Please forgive me if it takes a little time.

 

 

MeasurementBlues
User Rank
Blogger
Changing location
MeasurementBlues   2/9/2014 12:41:38 PM
NO RATINGS
antedeluvian, I think many of us have been through location changes. My biggest one was from Burlington, Mass. to Andover, Mass. with a stop in Sunnyvale. We were moving into the new Andover facility and I was in charge of moving a product line from Sunnyvale to Andover. It was a great experience and I got to spend six weeks in Silicon Valley. I was single at the time and thus didn't mind.

In 2011, I wrote an article about moving a calibration lab. See. Moving a lab is a monumental task.

antedeluvian
User Rank
Blogger
Re: Changing location
antedeluvian   2/9/2014 3:29:58 PM
NO RATINGS
Martin

I must admit that our move pales in comparason to the ones you are tal;king about. Nevertheless there are many frustrations, especially if the logistics haven't been well thought out. In our case we moved from a location where we were renting space within another organization to one that we own. So issues like stocking the bathrooms, kitchen, picking up the garbage and snowplowing were all new to us and someone has to look after that, but who? That is to say nothing about the responsibilty for the layout, fitting existing furniture iton that space, redeploying partitions, storage space and on and on. It didn't help that the guy organizing this first had bypass surgery and then a detached retina slap dab in the middle of all the preparations.

We are about 50% done with another 90% to go.

Radio
NEXT UPCOMING BROADCAST
EE Times Senior Technical Editor Martin Rowe will interview EMC engineer Kenneth Wyatt.
Top Comments of the Week
Like Us on Facebook

Datasheets.com Parts Search

185 million searchable parts
(please enter a part number or hit search to begin)
EE Times on Twitter
EE Times Twitter Feed
Flash Poll