reading from a parallel port

[Ak star]

Hi all,

I have bulit a photo-senors to read the orgin of a motor, when the senors isn't at the orgin it gives a voltage of 5 and at the orgin it is 0 volts. This information travels throught the parallel port and i want to read it on labview (reading from port 2). The code below is an example that i tried, i was trying to read from port 2.

[smercurio_fc]

What is your issue? Also, what do you mean by reading from "port 2"? Have you taken a look at the parallel port read/write VI that ships with LabVIEW? Open the Example Finder (Help -> Find Examples) and search for LabVIEW.

Also, have you verified that you parallel port is 5V tolerant? Many computer nowadays have 3V parallel ports. 

[Ak star]

My issue is to read the voltages from port 2. I don't know how to check if the parallel port is 5V tolerant. However, the computer i am using is an old computer.

[Dennis_Knutson]

You should check in device manager to see what the address of your second parallel port is. what you have now is the typical addrss for the first printer port. Also make sure the port is configured correctly. If I remember, there are directions with the shipping example (Search for 'Parallel').

Message Edited by Dennis Knutson on 03-22-2009 11:49 AM

[Ak star]

The address that i am using is the typical addrss for the first printer port.

[Dennis_Knutson]

Then your question makes no sense since you said a couple of time that you want to read from port 2. Do you actually have 2 ports or should we just subtract 1 from everything that you say?

[Ak star]

sorry i mean pin 2.

[Dennis_Knutson]

Okay, so what is the problem? Have you tried the example that comes with LabVIEW (Parallel Port Write and Read Loop) and have you configured the parallel port in the BIOS according to the instructions in the example?

[smercurio_fc]

Are you perhaps asking how to specifically get the value of bit 2? If so, then use Index Array to get the value from your Boolean array.

Have you gone through the LabVIEW tutorials? To learn more about LabVIEW it is recommended that you go through the tutorial(s) and look over the material in the NI Developer Zone's Learning Center which provides links to other materials and other tutorials. You can also take the online courses for free.

[Baji]

Hi Ak Star,

 Did u configured your parallel port as SPP(Standard parallel port) . If u connected your input to the pin2 then u need to read the staus of data bit 0.  what is the output u getting after u run your programme,Its always showing high\low? asking how to specifically get the value of bit 0? If so, then use Index Array to get the value from your Boolean array(as smercurio_fc said).

 smercurio_fc wrote

Also, have you verified that you parallel port is 5V tolerant? Many computer nowadays have 3V parallel ports. 

I like to know, what is 5V tolerant and 3V tolerant. do u mentioned TTL as 5V and CMOS as 3V or something else, please forward the infos or related links.