Parallel Port Does Not Work in Input Mode
- tommylight
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26 Dec 2016 21:05 #84714
by tommylight
Replied by tommylight on topic Parallel Port Does Not Work in Input Mode
Oh you did not mention a BOB, they can not be used for that. If you want to connect limit switches, that is OK, anything else and it gets more complicated.
The older paraports had a 5V level, new ones are 3.3V and most of them can tolerate 5V ( all that i have do ).
Again for limit switches you do not need to worry about levels, if you do not intend to use it on a plasma cutter.
It can be used for plasma too, but need good shielding on the cabling.
The older paraports had a 5V level, new ones are 3.3V and most of them can tolerate 5V ( all that i have do ).
Again for limit switches you do not need to worry about levels, if you do not intend to use it on a plasma cutter.
It can be used for plasma too, but need good shielding on the cabling.
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27 Dec 2016 22:21 #84769
by andypugh
Replied by andypugh on topic Parallel Port Does Not Work in Input Mode
The logic level of the p-port depends on the machine, it will be either 5V or 3.3V. However they are all 5V tolerant, as the spec requires that.
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28 Dec 2016 11:09 #84800
by rodw
If your BOB is a DB25-1205 with the 17 optocouplers, we tested it on the bench with a multimeter and 5 v power supply (no PC) on the weekend and confirmed that it works on both inputs and outputs. Eg. All pins show a voltage in them by default and they are active low so 0V is on. Grounding one of the BOB inputs drops the 5 v on the corresponding DB25 pin. Grounding one of the DB25 connector output pins, drops the voltage on the BOB output. In our case, a faulty riser cable from the motherboard was the problem. This is how I diagnosed the faulty cable. Replacing it got the BOB working properly
I found that because the input pins in the BOB end of the cable are mostly in line with the ground pins, it is easy to test the PC side of it with the BOB removed and shorting the cable input pins to a ground pin with a screwdriver. You should be able to monitor the change of state using Axis tools. I would do this first so you know the parallel port is actually working.
There is an option to run isolated power so it may be possible to run 3.3v on the PC side and 5v on the BOB side by removing the 2 links. You may need to put one of the links on the third unpopulated link so experiment without the PC connected.
Replied by rodw on topic Parallel Port Does Not Work in Input Mode
Found the problem... i have this chinese break out board with the 17 optocouplers(one on each pin). They are onedirectional... so... 60 euros wasted... Another question. Does anyone know what is the logic level of the parallel port and how safe is to connect direct all my input to the parallel port without breakout board?
i have only switches and one encoder. no motors relays etc. Thank you..
If your BOB is a DB25-1205 with the 17 optocouplers, we tested it on the bench with a multimeter and 5 v power supply (no PC) on the weekend and confirmed that it works on both inputs and outputs. Eg. All pins show a voltage in them by default and they are active low so 0V is on. Grounding one of the BOB inputs drops the 5 v on the corresponding DB25 pin. Grounding one of the DB25 connector output pins, drops the voltage on the BOB output. In our case, a faulty riser cable from the motherboard was the problem. This is how I diagnosed the faulty cable. Replacing it got the BOB working properly
I found that because the input pins in the BOB end of the cable are mostly in line with the ground pins, it is easy to test the PC side of it with the BOB removed and shorting the cable input pins to a ground pin with a screwdriver. You should be able to monitor the change of state using Axis tools. I would do this first so you know the parallel port is actually working.
There is an option to run isolated power so it may be possible to run 3.3v on the PC side and 5v on the BOB side by removing the 2 links. You may need to put one of the links on the third unpopulated link so experiment without the PC connected.
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- Todd Zuercher
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28 Dec 2016 13:55 #84804
by Todd Zuercher
Replied by Todd Zuercher on topic Parallel Port Does Not Work in Input Mode
I'm pretty sure the question was about using the parallel port in "in-mode" and using pins 2-9 as inputs, and that breakout board can't do it. You have to buy a breakout board that is set up for bi-directional. Such as a C10.
cnc4pc.com/motion-control/breakout-board...-interface-card.html
cnc4pc.com/motion-control/breakout-board...-interface-card.html
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