Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Next revision		Previous revision
daq-and-datalogging:documents:temperature-two-point-controller [2023/06/14 04:53] – created Scandiwebdaq-and-datalogging:documents:temperature-two-point-controller [2023/07/28 00:54] (current) – Arthur Brown
Line 1: Line 1:
-====== Temperature two-point controller ======+====== Temperature Two-Point Controller ======
  
 There are many types of control systems.  A control system manages and regulates the behavior of a device or a system.  Types of control systems are open-loop, closed-loop, logic, two-point, linear, proportional, and PID.  This article discusses the two-point controller.  A two-point controller is also known as a Bang-Bang controller or On-off controller.  There are many types of control systems.  A control system manages and regulates the behavior of a device or a system.  Types of control systems are open-loop, closed-loop, logic, two-point, linear, proportional, and PID.  This article discusses the two-point controller.  A two-point controller is also known as a Bang-Bang controller or On-off controller. 
Line 37: Line 37:
 If you wanted to use channel 0 of an E-TC to monitor a room’s temperature and control a heater to keep that room at 25 °C, you can configuration the Alarm dialog box like this: If you wanted to use channel 0 of an E-TC to monitor a room’s temperature and control a heater to keep that room at 25 °C, you can configuration the Alarm dialog box like this:
  
-{{https://files.digilent.com/resources/measurement-computing/Reference Images/InstaCal_BoardConfig_AlarmSettings.png?412x593}}+{{https://files.digilent.com/reference-images/InstaCal_BoardConfig_AlarmSettings.png?412x593}}
  
 Here we see Channel 0’s alarm set to enabled.  It is set to turn on when a threshold is exceeded, and the output will use active high logic. Here we see Channel 0’s alarm set to enabled.  It is set to turn on when a threshold is exceeded, and the output will use active high logic.
Line 50: Line 50:
 The E-TC and external wiring to the heater: The E-TC and external wiring to the heater:
  
-{{https://files.digilent.com/resources/measurement-computing/Reference Images/ETC_2pt_Ctrlr_schematic.png?759x394}}+{{https://files.digilent.com/reference-images/ETC_2pt_Ctrlr_schematic.png?759x394}}
  
 **Two Point Controller in DASYLab.** **Two Point Controller in DASYLab.**
 DASYLab has a built in module for 2 point control as part of all versions except DASYLab Lite. Here is what a basic two point control worksheet would look like: DASYLab has a built in module for 2 point control as part of all versions except DASYLab Lite. Here is what a basic two point control worksheet would look like:
  
-{{https://files.digilent.com/resources/measurement-computing/Reference Images/DASYLab_2pt_Ctrl.png?600x225}}+{{https://files.digilent.com/reference-images/DASYLab_2pt_Ctrl.png?600x225}}
  
 And the Layout: And the Layout:
  
-{{https://files.digilent.com/resources/measurement-computing/Reference Images/DASYLab_2pt_Ctrl_layout.png?896x508}}+{{https://files.digilent.com/reference-images/DASYLab_2pt_Ctrl_layout.png?896x508}}
  
 This is the basics of implementing a 2 point control.  There are some additional settings and options used here, but I wanted to keep focus on the process itself.  For more, please see the attached worksheet. This is the basics of implementing a 2 point control.  There are some additional settings and options used here, but I wanted to keep focus on the process itself.  For more, please see the attached worksheet.
Line 66: Line 66:
 LabVIEW does not have a specific 2 point control vi, but it can easily be resolved using a Less than/Equal vi as the decision maker.  Here is what a basic 2 point controller would look like in LabVIEW: LabVIEW does not have a specific 2 point control vi, but it can easily be resolved using a Less than/Equal vi as the decision maker.  Here is what a basic 2 point controller would look like in LabVIEW:
  
-{{https://files.digilent.com/resources/measurement-computing/Reference Images/LabVIEW_2pt_Ctrl.png?920x323}}+{{https://files.digilent.com/reference-images/LabVIEW_2pt_Ctrl.png?920x323}}
  
 And the Front Panel: And the Front Panel:
  
-{{https://files.digilent.com/resources/measurement-computing/Reference Images/LabVIEW_2pt_Ctrl_FrontPanel.png?792x369}}+{{https://files.digilent.com/reference-images/LabVIEW_2pt_Ctrl_FrontPanel.png?792x369}}
  
 This is the basic 2 point control implementation.  From the front panel, you can adjust the set point, and monitor the performance of the system.   This is the basic 2 point control implementation.  From the front panel, you can adjust the set point, and monitor the performance of the system.  
Line 79: Line 79:
 Here is the routine in the Timer_tick event used to loop through reading the thermocouple, determine if the 2 point controller should be on or off, and operate the digital bit controlling the relay and heater. Here is the routine in the Timer_tick event used to loop through reading the thermocouple, determine if the 2 point controller should be on or off, and operate the digital bit controlling the relay and heater.
  
 +<code>
 Dim ETC_Temperature As Double Dim ETC_Temperature As Double
  
Line 103: Line 104:
     Exit Sub     Exit Sub
 End If End If
 +
 +</code>
  
 And the form view: And the form view:
  
-{{https://files.digilent.com/resources/measurement-computing/Reference Images/VBNET2010_2pt_Ctrl_Form.png?732x394}}+{{https://files.digilent.com/reference-images/VBNET2010_2pt_Ctrl_Form.png?732x394}}
  
 This is the basic 2 point control implementation in Visual Basic.NET.  From the Form view, you can adjust the set point, and monitor the performance of the system. This is the basic 2 point control implementation in Visual Basic.NET.  From the Form view, you can adjust the set point, and monitor the performance of the system.
Line 122: Line 125:
  
 **Attachments**\\  **Attachments**\\ 
-[[ https://files.digilent.com/resources/measurement-computing/Reference Attachments/Two_Point_Controller.zip | Two_Point_Controller.zip]]\\  +[[ https://files.digilent.com/reference-attachments/Two_Point_Controller.zip | Two_Point_Controller.zip]]\\  
-[[ https://files.digilent.com/resources/measurement-computing/Reference Attachments/Two Point Controller.llb | Two Point Controller.llb]]\\  +[[ https://files.digilent.com/reference-attachments/Two Point Controller.llb | Two Point Controller.llb]]\\  
-[[ https://files.digilent.com/resources/measurement-computing/Reference Attachments/twopointcontroller.DSB | twopointcontroller.DSB]]+[[ https://files.digilent.com/reference-attachments/twopointcontroller.DSB | twopointcontroller.DSB]]