[GreenKeys] Current Loop Converter

[Bill Horne]

Dave Hunter wrote:
> Hi All:
>
> Does anyone have for sale a current loop to RS232 converter 
> which is selectable between 20 or 60 ma loops?
>
> Alternatively, can anyone recommend a commercial product 
> which they use to drive an ASR-28 from a computer, also, to 
> drive an ASR33 from the computer (future project)...
>
> I realize these can be built, but as a diabetic with 
> eyesight which is now beginning to give me problems, it 
> will be simpler to purchase a suitable pre-wired device...
>
> Dave, VY2AC
>   
*Dave,

I seached for "(rs232,rs-232,rs232c,rs-232c,rs-232-c) current loop" on 
e-pay, and came up with several offers, which average about $50.

Here are the first two:

http://tinyurl.com/ya2dtnk
**http://tinyurl.com/yezs64r

HTH.

By the way, I've just realized that I don't know what the "standard" 
current loop value was: I'm used to 60ma from Model 15 machines, but I 
don't remember what the Model 33 used, and I never worked on the Model 
28. I know the 33's had a built-in driver assembly that used transistors 
to deliver ~500ma to the magnets, but I don't recall the default input 
current value during "marking" conditions.

Was the current value a strapable option in the 15/28/whatever, or did 
the 20ma machines have to have the special selector magnet assemblies 
that reset the armature mechanically before each pulse?

Bill, W1AC
*

-- 
E. William Horne
William Warren Consulting
Computer & Network Installations, Security, and Service
http://william-warren.com
781-784-7287