Michael Lloyd

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About Michael Lloyd

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  • Birthday 06/01/58

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  • Gender Male
  • Location Texas
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  • Interests Photography, Flying, Electronics, Long Range Shooting, Reloading, Fishing, Hunting

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  1. 0-10V output drops when connected to Micrologix 1400

    Can you share how you're wiring the loop?
  2. sine wave generation for frequency tests purpose

    I've never had the luxury, need, or desire to continuously disrupt the process by using a sinewave for a setpoint. I'm sure you haven't either. Typically you step the setpoint, analyze the result, adjust tuning parameters, step change, etc. Maybe the OP is working on an exercise intended to teach loop tuning?
  3. sine wave generation for frequency tests purpose

    This?: http://www.ni.com/tutorial/6450/en/ Controlled by a PLC or controlled by a PID loop in a PLC?
  4. sine wave generation for frequency tests purpose

    I don't think you're dense, but if you are you have company :)
  5. sine wave generation for frequency tests purpose

    I think you can use a PID loop with the analog output fed back to the PV of the loop, then vary the gain and integral values to adjust the output "characteristics". Tap off of the output for an analog representation of the sine wave. I am struggling to understand what type of signal you are looking for. If analog, what is the scale or limits? 0-100%; -100% - 0 - 100%? Actual frequency and amplitude? Frequency in Hz. kHz? I don't think you are looking for a Boolean value but I don't want to assume so I'll ask.
  6. sine wave generation for frequency tests purpose

    Ok... scratch the AOI. I almosts always over complicate the first draft and this was no exception. Besides that it has errors.  How do you see this function working?  The idea behind what you want to implement isn't clear. Are you going to drive an analog output? Linear motor driving a pump? 
  7. sine wave generation for frequency tests purpose

    Thinking thru the AOI over lunch- I think I used the wrong value for t. <-- scratch this, more thinking below
  8. sine wave generation for frequency tests purpose

    Removed. Not valid
  9. sine wave generation for frequency tests purpose

    There's a SIN function block and you can use SIN( ) in structured text but there's more to it than just the SIN portion of the equation. The value for t seems to be as easy as using a periodic task and then extracting t with: GSV(Task, THIS, Rate, TaskRate); // Get the rate of the task. The units are microseconds t := TaskRate / 1000000;; // Convert Microseconds to Seconds I may tinker with writing an AOI for this if I can find some free time today
  10. sine wave generation for frequency tests purpose

    There may be an easier way but you could write a structured text routine for the SIN function (copy / paste from Wikipedia): Its most basic form as a function of time (t) is: where: A, amplitude, the peak deviation of the function from zero. f, ordinary frequency, the number of oscillations (cycles) that occur each second of time. ω = 2πf, angular frequency, the rate of change of the function argument in units of radians per second , phase, specifies (in radians) where in its cycle the oscillation is at t= 0.   When  is non-zero, the entire waveform appears to be shifted in time by the amount /ω seconds. A negative value represents a delay, and a positive value represents an advance.  
  11. PID Control Loop

    You're not vaporizing or condensing on the water side so M*Cp*Delta T can used to calculate the amount of heat being input and removed in the system. The steam side is a little more difficult and only useful if you're trying to evaluate the heat exchanger. M = mass flow rate, #/Hr Cp = Specific heat of the fluid. Water is easy. It's 1 Delta T is obvious Hopefully you have flow measurement. Most of the time (in my industry) liquid flow rate is displayed in GPM (gallons per minute) or BPH (barrels and hour). If GPM it's pretty easy to get #/Hr. #/Hr = GPM * 500 * Sg (specific gravity). Water (in your temperature range) has a specific gravity of 1.0-ish, which makes the calc easy. Know how much heat the exchanger is capable of producing (Bob's warnings about hot spots and calcification are spot on) vs how much heat is required is a good start to analyzing whether or not you can speed the process up and it will tell you if the exchanger is fouled. I doubt if you can. You may even have a fouled heat exchanger if it's been in service for a while and the steam system water isn't treated properly. There should be an exchanger spec sheet available. Sometimes (rarely these days) the nameplate has the info that you need. Sensor 1 is your PV since you're are blending cold water with hot water and the desired temperature of the blend is your target.
  12. Add-on Profile install help

    This: EDS allows RSlinks to ID the device (which is why you install them from RSLinx I guess) while AOP tells the logix how to handle the device" seems to agree with you. This is a post by Ken Roach (also a valued member here) from another forum:   which leads me to - does the AOP you installed match the module series?
  13. Add-on Profile install help

    Ok... just making sure it wasn't typo for AOI. Any chance that you need to update the EDS file? https://literature.rockwellautomation.com/idc/groups/literature/documents/pm/1756-pm002_-en-d.pdf    
  14. Temperature Sensor's Raw value Scalling

    For some reason I see where other people use the max range of the sensor. You don't have to do that. The PT100 RTD range is -200° C to 600° C (-328° F to 1,112° F). If you only need a small piece of the range then scale it that way. Your PID loops will hug you (from 6' away, while wearing a mask that dust can penetrate) for it. The following is working fine (PT100) in dozens of locations. The range changes but functionality doesn't. This is (clearly) for the IR6I
  15. Add-on Profile install help

    What is an AOP?