Re: [CAD_CAM_EDM_DRO] Hp 7475 Plotter Servo's

Tom H.,
I have negative voltage coming off of pin 3 of the computer's com1 port.
But I'm not convinced that the computer is sending out any data from the
com1 port. When I send a sting of commands through the port using DOS, I
did not get any change in the voltage across the pin. In fact when I send
the string, my curser hangs up and does not let me type any more commands
without first exiting the DOS window and then opening back up and starting
over.

I think at this point I am going to try and find a DOS only computer (No
Windows) laying around and try it.

Still trying to get the plotter to work.

Victor A.

----- Original Message -----
From: "caedave" <caedave@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Friday, September 30, 2005 6:01 AM
Subject: Re: [CAD_CAM_EDM_DRO] Hp 7475 Plotter Servo's


> Took a look on HP's site (Not the best to navigate around) and
> did eventually find some info on the 7475's including full pin out
> listings, Dip switch positions, test procedures and setting up.
>
> Limited amount on the error codes (lights) listed below.
>
> 1. Error light dim, slow blink :-
> Plotter not active but performing power management.
>
> 2. Error light on steady :-
> View Button pressed or plotter in paper load mode
> (Pinch wheel lever Up)
>
> 3. Error Light fast blink :-
> I/O error, Paper jamb error, HP-GL error.
> For these it then references certain sections of the manual.
>
> Dave M.
>
> ----- Original Message -----
> From: "Tom Harrison" <TomH-CNC@...>
> Subject: Re: [CAD_CAM_EDM_DRO] Hp 7475 Plotter Servo's
>
>
>> Don't forget: It also flips data receive and transmit (pins 2 and 3).
>>
>> Try this: using a digital voltmeter, measure the voltage at pins 2 and 3
>> using pin 7 as a reference. The one with an active negative voltage
>> (between -5 and -15 volts) is the pin the device is using to send data
>> out
>> to the world. On your plotter and on your computer (use a 9-pin to 25-pin
>> convertor if necessary), they must be on different pins to communicate.
>> Then apply jumpering if necessary, to satisfy the RTS/CTS and DSR/DTR/DCD
>> requirements of each end.
>>
>> Realize also that some interfaces actually USE the other control signals
>> to
>> throttle data flow so as to not overwhelm buffers. Not all use the
>> character-based throttling, like XON/XOFF and the like.
>>
>> More details if you need....
>>
>> Tom Harrison
>
>
>
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