[TowerTalk] SteppIR problem

[Roger (K8RI)]

> Roger (K8RI) wrote:
>
>>>I'm not at all familiar with the SteppIR design, but I've
>>>
>>>
>>
>>Nor am I, but I have many years working with process control and 
>>positioners
>>prior to moving into computer science.
>>Which brings up my question:  How does the system know the motors have 
>>moved
>>the tape/elements to the proper length? Hopefully they don't just count 
>>the
>>pulses to the motors.
>>
>>Roger (K8RI)
>>
>>
> Yes, that is exactly how it works.  It does have a recalibrate function
> which drives the elements back into the housing and oversteps the pulses
> so that it is now sure where the antenna is.

When it came to accuracy we always had problems with that type of system 
when things didn't work right.   IOW when the system recalibrates it starts 
out accurate, but if there is anything that hinders the steps, be it enough 
drag to prevent the motor from fully stepping,  not enough current, and in 
some rare instances misshapen or even dropped pulses. The more pulsese to 
get to the target position that larger the potential error.  I reiterate 
that this was only when things didn't work right and in the chemical 
industry we had some strong safety issues with maintaining accuracy so we 
used output signals much like you find on the large C-Band satellite dish 
positioners or even on modern radio VFOs. We used magnetic, but they can be 
optical or even mechanical switches to verify we were really/accurately 
getting to the positions we expected. Of course this added complexity and 
cost to the system but we *almost* always knew where the positioners were 
setting.

73

Roger (K8RI)

>
> Jerry
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