Incorporation timers and out put signals to the VI

[Daniel 1]

Hello gentlemen, Unfortunately I'm really new in Lab view but we have to proceed. We have cDAQ-9172 8-slot USB 2.0 Chassis for Compact DAQ. Till present time we've just collected signals +/-20 mA   from pressure transducers, LVDT etc., thermocouples and charted them on graphs /charts.We'd like to incorporate to the Vi timers and output signals to the solenoids.Timer#1 selects continues 24V supply to one of the solenoids for programmed time then timer#2 selects the ON or OFF time (i.e. 1 sec ON / 2 sec OFF) to operate solenoid.Will you direct me to some examples that can help me to set up this test properly?

[Jason_D]

Daniel 1,

I am not exactly clear on what you mean by VI timers?  Could you explain what you are trying to achieve?  By timer #1/2 do you mean buttons that toggle different actions?  For example do you need the on/off time to be settable?  Are you simply trying to use both your pressure transducers and thermo couples in the same VI?  Any additional info you can give us on what you are trying to get the program to do will be extremely helpful.

[Daniel 1]

Hi Jason,

We are testing the actuator:  Pressure transducers, LVDT,thermocouples etc. connected to this actuator and we are using Labview to collect, chart and analyze data from these devises (very successfully). We are stepping the actuator by opening and closing the solenoids .In the present time we are using electrical stepping box equipped with OMRON timers to operate these solenoids 24VDC (pressurize/depressurize actuator cylinders with working liquid) .Timer (programmable by user) allows us to configure 24VDC supply to one of the solenoids (chosen by user).Other timer is settable for on/off time (close/open solenoid).Please see the one of the standard sequences.Stage1 .Solenoid#1 ON-LINE - 1sec. ON (24 VDC supplied) then 1 sec.OFF (0 VDC supplied).This sequence should be repeated 20 times.(duration is 40 sec), during this time solenoid#2 is OFF-LINE 0 VDC supplied.Stage2.Solenoid#2 ON-LINE - 1sec. ON (24 VDC supplied) then 1 sec.OFF ( 0 VDC supplied).This sequence should be repeated 20 times.(duration is 40 sec), during this time solenoid#2 is OFF-LINE 0 VDC supplied.ON-LINE, ON/OFF times are programmable by user. 

We'd like to operate solenoids from the screen by buttons that toggle different actions (ON-LINE time set up, ON/OFF of output signal). Our goal is to incorporate  "stepping box" to the program and use Labview and solenoids only.          

Thanks,

Daniel.       

[Jason_D]

Daniel1,

I assume that you meant in "stage2"  that solenoid #2 cycles off then back on while solenoid #1 is OFF-LINE?

You mentioned a 9172 CDAQ Chassis, but what modules do you have for this chassis that will allow us to control the solenoids?  You mentioned that the solenoids have either logic high (24V) or low (0V) what is supplying the 24V?  Are you using an LabVIEW and your CDAQ module to control a relay gating the external supply?  Programming this in LabVIEW should not be too difficult and I will set you up with some examples as soon as I know a little bit more about your setup and exactly how we want the program to control the solenoids.

Message Edited by Jason_D on 01-07-2009 05:03 PM

[Daniel 1]

 Jason,

We have currently installed NI 9481 Relay Module, NI 9265 Current Output Module, and NI 9219 Universal AI Module. We have 24VDC supply source that provides accurate 24 VDC supply to the channels.

We don't know how to control a relay gating the external supply.

Thanks,

Daniel. 

[Jason_D]

Daniel 1,

Here is a good KnowledgeBase article that describes how to get the relay module working.

I am assuming that software timing is acceptable for the 1 second on/off.  If so I would start with the Writ Dig Chan.VI.  This will allow you to once you change the write to the correct format (Digital>Multiple Chanel>Single Sample>1D Boolean) to pass an array of boolean to the write and wait 1s between toggling.  You can use a case statement connected to Knob to select Stage 1/2 which will determine which of the digitial lines you should toggle.  Finally for changing the wait time use a numeric control and have this (times 1000, because wait VI wants time in ms) input to the wait.vi.

Please let me know if you get stuck or have other questions!