Relay switching with error inputs. Requirements?

[ConradH]

I am brand new to NI. I would like to use Labview ( graphics rather than software language) for a PC to relay board interface. The input will be a single microswitch for sequential relay operation (up to 16 relays). There should also be a programmable delay per relay, as well as error input capabilities.

Can anyone suggest a start-up package as well as what would be required for this design.

[johnsold · Accepted solution]

ConradH,

Do you  want someone to do the job for you or do you want to learn LabVIEW, hardware I/O, and system design yourself?

You mentioned LabVIEW and relays but were not specific about what other hardware or software you have.  Do you have some kind of Digital Input and Output device?  If so which one?  What kind of relays? What are the power requirements for their coils?

What is the range and resolution of the delays? What are the initial and final conditions for your system?

You should start by going through the online tutorials about LV.

There are several examples showing how to do digital input and output.  Those would be good starting points.

Lynn

[ConradH]

Hi Lynn

As an overview - It is an autosampler from a scientific instrument. What I want the sampler to do (via the microswitch) is to trigger the program/interface to select a externally mounted solenoid (24VDC - 8watts). The selection process must be sequential, starting from solenoid 1 to finish at a user select 1-16. At the end of the completed sequence ,it must start at 1 again to repeat the process.

I have built the system using normal gates and logic, together with a heap of 555 delay ccts and it is working fine - albeit clumsy.

I do not have any i/o devices yet, hence the request. As basic as possible would probably suffice. The onboard relays would probably be good enough to switch the solenoids.

The programmable delay (solenoid on) should be variable from 10 seconds to about 1 minute.

To end of - I would like to learn Labview initially, but if there are some examples available, to negate the start-up time somewhat, I would rather go that direction.

[johnsold]

Since your timing requirements are quite slow, nearly any device with 17 digital I/O (one input for the switch and 16 outputs to the solenoids) would work.  Many DAQ devices will not drive your solenoids directly.  Use devices from the ULN200x series of drivers to amplify the logic signals to solenoid drive levels.

This should be a fairly straightforward program.  Work through the tutorials and try something.  If it odes not work, post your VI here for help.  People who participate in this Forum are mostly volunteers.  We are glad to help someone learn, provided you put in your effort.

Lynn

[ConradH]

Will give it a bash

Thanks

[ConradH]

Sorry about the delay, but I have been out the country for a while now. I am back in front of the PC to try and learn something (old dogs and new tricks - probably true) I have downloaded an example which looked very promising, but it failed to open. The error message list ended up taking more time to sort out than the project itself. Now I am not sure if I have done it correctly. Is there a very specific way to "install" this types of VI or what else can I try?

Conrad

[HeatherBaker]

Hi Conrad,

Can you elaborate on the error?  Are you missing subVIs, missing dlls, etc?  Can you provide a link to the example?  Another helpful resource for you may be www.ni.com/gettingstarted which has the basics of LabVIEW and hardware.