PID output issue

[JtotheB]

You are correct that once you have the hardware connected, that will act as your system. As for the questions about the terminology, here are some explanations;

Static gain; Also known as process gain. This is basically how much the system responds as the input changes from steady state to steady state. For example, if a one volt excitation leads to a three volt system response, the process gain is three. More information here.

Lag; The plant model in that example has a built in lag compensator to simulate system phase lag. This variable is the phase lag time of that compensator. More information here.

Dead Cycle; This is a count of the number of loop iterations to delay the controller response. This is to simulate delay in the system.

Load; This is a bit more complex, but I will try my best to explain this in a sense that is analogous to your system. Imagine that you are trying to keep an object at a constant temperature. In this case, the load will be the amount of energy that you need to input to that object to keep it at that temperature. So, obviously, the load can vary based on a number of factors (heat capacity of the object, mass of the object, convective heat loss, radiation, etc.). For most systems the load is zero, but for thermal systems, where you are "accumulating" energy in an object, the load can be important.

Deadband; Deadband is a range of inputs that you can give to a system that will illicit no response from the system. For example, if I am trying to move an object the deadband will be the range of forces lower than the force I have to exert to overcome friction and start the object moving.

Noise Level; The amount of noise you expect from your output readings as a percentage of the maximum system output. If you are reading from 0-10 Volts, and you know you have a range of 250 mV in noise, your noise level is 2.5%. Generally speaking, a safe assumption for most systems is 3 to 5 percent.

Initial PV; Initial Process Variable. This is the initial state of your system measurement. So, if your system starts at 25 degrees Celsius and you are trying to heat it to 100 degrees, 25 is your initial process variable.

[kunj.acharya@utoronto.ca]

Hello,

So I have finally recieved my USB 6211 I/O module. I have connected it to my system and I am still having trouble controlling the system. I was trying to trouble shoot the process and program. And here my following questions:

1.) Does USB 6211 support CMOS signal (for RFena: Radio frequency enabaled). I looked up in the manual and I could not find which channel supports it. However, I recall speaking with NI application engineers and the conclusion was it does support CMOS signals. So which channel on 6211 is for CMOS signal?

2.) I believe I need to perform scaling for temperature control. So what I did was I adjusted IR-sensor for temperature range of 0 to 100oC and for 0 to 10V signal. So 0V is 0oC and 10V is 100oC and thus create a linear relation between Temp and Voltage. Now in the DAQ, I was performing scaling in the channel that is connected to my IR-sensor. And when I do this, there is a graph that comes up and preety much I have to give slope and y-int but this is not yet making much differencee. And this is because the reading in IR-sensor shows 24.8oC while I get a reading in the front pannel between 18 to 19 oC.

Thank you

Kunj

[JtotheB]

Any of the digital lines will support your CMOS signal, unless you are doing an analog application with a CMOS circuit for some kind of mixed-signal RF application. In that case, use one of the analog lines. As for the scaling, you may want to check your sensor's documentation. Very few sensors have linear scales, and you may get more accurate readings by more closely matching the scale to the sensor response.

[kunj.acharya@utoronto.ca]

Thanks for the reply. However how do I get the option for configuring the COMOS output signal in the digital line as I am only able to see analog input and output lines in the Physical channel that is seen when the DAQ is being configured. Can you give me step by step  procedure to configure the CMOS digital output from DAQ (specifically USB 6211).

Thanks

[JtotheB]

You may need a pull up resistor, but I'm not sure what you mean. Could you elaborate a bit more on the connection that you want?