Time Proportioning PID Controller, On/Off Output On Lookout Version 5.1

[Sugarman]

I need a time proportional PID controller with an on and off output developed for Lookout Version 5.1. I can't find one from NI application library that will serve as example and template for our application. Your help is greatly appreciated. Thanks!

[Jeff M]

Here are a few PID resources for Lookout: 1. Using the PID Object in Lookout In this example, a PID controller is implemented using two pots and a PID object. The Setpoint and the Manipulated Variable are displayed on a HyperTrend. The PID object compares the Manipulated Variable to a Setpoint. If there is a difference, it calculates the error and adjusts its output to compensate until the Manipulated Variable is equal to the Setpoint. http://sine.ni.com/apps/we/niepd_web_display.display_epd4?p_guid=B45EACE3E6E556A4E034080020E74861&p_node=DZ52186&p_source=External 2. Controlling Fieldbus PID Loop in Lookout This process uses the Fieldbus PID driver object to control a Foundation Fieldbus PID loop. The example allows you to control the PID parameters and setpoint, switch from automatic to manual control, and set the manual output level. This example was built using FieldBus version 2.3.5 http://sine.ni.com/apps/we/niepd_web_display.display_epd4?p_guid=B45EACE3EA4D56A4E034080020E74861&p_node=DZ52375&p_source=External 3. Lookout PID Auto Tuning Example (attached with documentation) This example shows how to use the PID object and how to make an auto tuner for the PID. You can connect your own hardware to the example or use the built in software simulation. The auto tuner is based on the Zeigler and Nichols open-loop (Step Test) procedure. Most of these examples were developed for Lookout 4 and above. Hope this helps! Jeff M. Applications Engineering National Instruments

[Jeff M]

Let's try this again...

Here are a few PID resources for Lookout:

1. Using the PID Object in Lookout

In this example, a PID controller is implemented using two pots and a PID object. The Setpoint and the Manipulated Variable are displayed on a HyperTrend. The PID object compares the Manipulated Variable to a Setpoint. If there is a difference, it calculates the error and adjusts its output to compensate until the Manipulated Variable is equal to the Setpoint.

http://sine.ni.com/apps/we/niepd_web_display.display_epd4?p_guid=B45EACE3E6E556A4E034080020E74861&p_...

2. Controlling Fieldbus PID Loop in Lookout

This process uses the Fieldbus PID driver object to control a Foundation Fieldbus PID loop. The example allows you to control the PID parameters and setpoint, switch from automatic to manual control, and set the manual output level. This example was built using FieldBus version 2.3.5

http://sine.ni.com/apps/we/niepd_web_display.display_epd4?p_guid=B45EACE3EA4D56A4E034080020E74861&p_...

3. Lookout PID Auto Tuning Example (attached with documentation)

This example shows how to use the PID object and how to make an auto tuner for the PID. You can connect your own hardware to the example or use the built in software simulation. The auto tuner is based on the Zeigler and Nichols open-loop (Step Test) procedure.

Most of these examples were developed for Lookout 4 and above. Hope this helps!

Jeff M.

Applications Engineering, National Instruments 

[Sugarman]

Hello Jeff M.,

Thank you for spending your time with me. I have tried already the two PID object application examples that you have mentioned, but unfortunately, they donot fit my requirement. The output of those examples are exhibiting an analog signal. What I need is a Time Proportioning PID controller functioning as relay output where the cycle time is adjustable and responsive to PID parameter adjustments.Please consider my requirement. I simulated this in  a single loop PID controller with the following setting of parameters. This are my configurations as follows:

Template Discription: Single Loop with local setpoint

Control Output Type:  Relay Output

Control Action : Reverse

Analog Input:  4-20mA

Engineering High: 100

Engineering Low: 0

Decimal Places: 2

Cycle Time Output (1.0 to 300.0 seconds for time proportioning or “ OnOf” for On/Off

             Control: 1.0

Output On/Off Hysteresis Value: 0.0

These are just some of  the parameters settings of Level 2 to E on an ABB single loop PID controller that we need to input to function as PID Time Proportioning Controller with relay output. We wanted to have this on Lookout for our controlling action.

We have already tried using the Pulse Width Modulation using the Pulse object, though the pulse width varies according to the analog output of the PID object say, 4-20 mA), but it does represent the PID function to control the manipulated variable as the single loop controller is doing it. I suggest NI develop a PID object that all you have to do is just select your template for your application and, “presto!”- templates to function such as, Ratio Station, Ratio Controller, Cascade, Single Loop with Feed-Forward, Auto/Manual Station with low signal selection, etc…wow! this will make our job of developing a lot easier and time-saving rather than making a lot of object combinations and and expressions. I am looking forward to this development. Please note that our Lookout is connected to an Omron  PLC wherein the output at the PLC output module will drive a solenoid valve to modulate the control valve to control the manipulated variable. Thanks

Sugarman