Re: Rambling hydraulic post that was: Multiple syncronized spindle question.

[Dave Engvall <dengvall-at-charter.net>]

Hi list:
Not that I've done this but controlling the temp of the  oil might help.
In this case one might have to warm to start with and then cool to maintain
but control to 0.1 C is pretty easy in a well stirred bath and you can get
two more orders of magnitude with out breaking the bank.
Dave

On 9/27/02 3:24 PM, "Ray Henry" <rehenry-at-up.net> wrote:

> 
> 
> Hi Howard
> 
> As a matter of fact, there is thermal compensation built into the EMC
> code someplace.  I am not certain where it is and whether it can be
> tapped to do more than the length of an axis but it is in there.
> 
> Ray
> 
> BTW -- thanks for snipping.
> 
> On Friday 27 September 2002 10:36 am, you wrote:
>>> Ray Henry says:
>> 
>> snip
>> 
>>> I wrote a digital controller for a hydraulic load frame.  It works
>>> very
>> 
>> well,
>> 
>>> except that it does have significantly lower errors once the fluid is
>>> up
>> 
>> to
>> 
>>> temp.  I am porting the software from dos to RTlinux to see if I can
>>> clear things up using a floating point controller, because I am
>>> having numerics
>> 
>> issues.
>> 
>> and snip some more
>> 
>> Would it be worth it to take a temperature reading of the hydraulic
>> fluid and based upon the temperature adjust variables to compensate for
>> the increased viscosity until the machine warms up?  I know some high
>> end CNC mills compensate for differential expansion of the glass scales
>> and the milling table.  Just a thought.
>> 
>> Regards,
>> 
>> Howard Bailey
>