blue5t1050
Member
I currently need some assistance for a PLC project that I have. Currently I am taking a PLC course that hasn't been very fruitful, but have found more information for many of my questions so far amongst the numerous posts. My PLC knowledge is limited, but growing with each new post, YouTube video, etc. that I have encountered. Not so much with the class. It is the instructor's first time teaching it and my first time learning it.
I have to control the conductivity level of a boiler system by means of a temperature and conductivity probe. Those are the two control variables. My process variables are two motor actuated valves.
I am using a Micrologix 1100 1763-L16DWD with 1762-IF20F2 analog I/O expansion card. The temperature probe sends out a 4-20mA signal and the conductivity probe also sends out a 4-20mA signal. I have already discovered the switch settings by using the manual and this forum. The output goes to two motor actuated valves that are controlled by 4-20mA each.
In class we use a PLC-5/20E with simulator card (8 switches and 8 LED outputs), which originally confused me between the differences. After much trial and error I discovered that I only had to go to the word level addressing for the Micrologix 1100.
My current speed bump is finding more information concerning the implementation of a PID block. I want to use proportional control to start, but would like to see how PI may work. I have read through the forums to not preface the PID control with ANYTHING. I created a state diagram and sequence of operations that should take place. In order to have periodic blowdown take place, I want to use a timer. But, I was thinking about using the DONE bit of a TIMER, prefacing the PID block, but avoided it after research.
On the same token, it seems as though I can run a subroutine for the PID. The catch is that we are no where near subroutines in my class. Quite a bit of my learning has been outside of my class. If I created a subroutine for a PID block, can I also do one for my SCP's? I have some questions about SCP's as well, but I had a jumpstart with this forum and YouTube.
Questions:
Can I have some wisdom in regards to PID blocks, SCP's, and running them in subroutines? Base example for me to trial and error implementation?
Thank you.
I have to control the conductivity level of a boiler system by means of a temperature and conductivity probe. Those are the two control variables. My process variables are two motor actuated valves.
I am using a Micrologix 1100 1763-L16DWD with 1762-IF20F2 analog I/O expansion card. The temperature probe sends out a 4-20mA signal and the conductivity probe also sends out a 4-20mA signal. I have already discovered the switch settings by using the manual and this forum. The output goes to two motor actuated valves that are controlled by 4-20mA each.
In class we use a PLC-5/20E with simulator card (8 switches and 8 LED outputs), which originally confused me between the differences. After much trial and error I discovered that I only had to go to the word level addressing for the Micrologix 1100.
My current speed bump is finding more information concerning the implementation of a PID block. I want to use proportional control to start, but would like to see how PI may work. I have read through the forums to not preface the PID control with ANYTHING. I created a state diagram and sequence of operations that should take place. In order to have periodic blowdown take place, I want to use a timer. But, I was thinking about using the DONE bit of a TIMER, prefacing the PID block, but avoided it after research.
On the same token, it seems as though I can run a subroutine for the PID. The catch is that we are no where near subroutines in my class. Quite a bit of my learning has been outside of my class. If I created a subroutine for a PID block, can I also do one for my SCP's? I have some questions about SCP's as well, but I had a jumpstart with this forum and YouTube.
Questions:
Can I have some wisdom in regards to PID blocks, SCP's, and running them in subroutines? Base example for me to trial and error implementation?
Thank you.