2 stamp 2s connected

desz

· I have 2 stamp 2s connected together the second one counts sheets of paper on a printing press the first is connected to a pc via the serial port on a requst from the pc the first stamp interrupts the counting and gets the total.
This works fine but only when the counting stamp is connected to a debug terminal. If the·debug terminal is disconnected·it·fails intermittently.
Can someone please·help.
·Regards
Desz

Post Edited By Moderator (Joshua Donelson (Parallax)) : 10/23/2009 3:27:35 PM GMT

stamptrol

Desz,

Welcome to the forums. Please always use a descriptive Subject.

If I understand you correctly, if only one stamp is used (the counting stamp), the count is shown correctly on the debug screen and when the communication link is used it "fails".

I suspect the actual failure is due to having the multiple devices trying to do their own thing without regard to what the others are doing. As an example, as the counter is counting, it cannot really be interupted until its gets to its SERIN command and actually hears the other stamp asking for an update. Similarly the Stamp at the PC will not hear the PC unless it is actually sitting on the the SERIN when the PC requests an update.

Some of these issues can be overcome with better handshaking and taking advantage of the fact that the PC has a comm buffer and therefore can receive data anytime.

Show us the connections you're using and I'm sure you'll get some more things to check.

Cheers,

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Tom Sisk

http://www.siskconsult.com
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Chris Savage

You can add a descriptive subject to your post by clicking the pencil icon to the top right of the message.

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Chris Savage

Parallax Engineering
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