MESA THCAD-10 trouble

More
13 Feb 2021 11:53 #198670 by eslavko
Hello...

Long time ago I bought THCAD-10 card, but before card was arrived the my project was abandoned.

But now I have other project and I want to use that card lying in original package all that years and found that output is strange. As from datashet seems that it should be linear Voltage to frequency but as I supplyed voltage from power supply with 1V step and measuring results with oscilloscope I found that output seems more logharitmic than linear. Is That normal???

The jumpers was in Unipolar and F/128.

Attached is pdf with measurements. The 0V and 10V calibration from THCAD sticker seems to be valid. But linearity not.
Attachments:

Please Log in or Create an account to join the conversation.

More
13 Feb 2021 12:56 #198674 by rodw
Replied by rodw on topic MESA THCAD-10 trouble
Why didn't you measure frequency in Hz?

Every other example where I have seen people do similar measurements, the device was linear.

Please Log in or Create an account to join the conversation.

More
13 Feb 2021 13:25 #198677 by eslavko
Replied by eslavko on topic MESA THCAD-10 trouble
It has same result. 1/f=time and vice versa. So linearity should be same in both directions.

Please Log in or Create an account to join the conversation.

More
13 Feb 2021 14:57 - 13 Feb 2021 15:03 #198680 by PCW
Replied by PCW on topic MESA THCAD-10 trouble
Here's the (scaled in Khz) inverse of your data:

0,0.940733772
1,1.597444089
2,2.304147465
3,2.96735905
4,3.663003663
5,4.273504274
6,4.95049505
7,5.617977528
8,6.289308176
9,6.944444444
10,7.575757576

And here is the plot of that data



The frequency with respect to input voltage is linear, the period is not. The V-F linearity is typically better than .02%
Attachments:
Last edit: 13 Feb 2021 15:03 by PCW.

Please Log in or Create an account to join the conversation.

More
13 Feb 2021 17:35 #198697 by eslavko
Replied by eslavko on topic MESA THCAD-10 trouble
Hmm indeed with frequency is linear...
...but sadly just destroyed the card as I plug wrong connector on wrong place, supplyed 10V on +5V input.

Please Log in or Create an account to join the conversation.

More
13 Feb 2021 20:01 #198709 by rodw
Replied by rodw on topic MESA THCAD-10 trouble

Hmm indeed with frequency is linear...
...but sadly just destroyed the card as I plug wrong connector on wrong place, supplyed 10V on +5V input.


That must be your pennance for doubting the great PCW

PS. Now I don't know what smiley to add :(

Please Log in or Create an account to join the conversation.

More
14 Feb 2021 07:47 #198781 by eslavko
Replied by eslavko on topic MESA THCAD-10 trouble
repair or not to repair. That's question now. probably all the chips on computer side are toasted. all except isolator are cheaps...

Please Log in or Create an account to join the conversation.

Time to create page: 0.177 seconds
Powered by Kunena Forum