Hi, How're you doing?
I've been trying to tune my PLC, a AB micro 820, for such a long time and I haven't yet noticed what I've done wrong.
I have a water level system consisted of two tanks, where one of then is only to storage the water that will be send to the other tank using a pump. The pump is controle through a frequency inverter and the inverter receives signal from the controller. The water level is measured using a ultrasonic sensor. The output flow of the tank is constant.
I've applied a step in the system and through its answer i was able to identify the transfer function of the plant.
I than, tried to apply Ziegler-Nichols to tune the system, but it didn't work. The controller output was binary, since the system is limited in the range 0-7v. I concluded that this happened because the gains were values too elevated.
My next move was trying to tune it using Mathlab, I used the Autotuner app, and noticed the it works really good for P and PI tuning the only thing i had to do is divide 1 by I parameter, but when i tried to apply PD or PID it doesn't worked. I've also realized that the PI part of the controller have the following transfer function Kp(1 + 1/(I*s))
I tried to find the block diagram or the transfer function of the PID Function Block but i haven't found anything.
Have you ever used a AB Micro800 series plc and used this PID function block?
Have you succeed tuning it?
Do you know how the derivative part of this function block works?
Do you have any idea of what could i do?
Do have a ladder block logic so it wouldn't be necessary using AB Function Blocks?
Ps: I've also tried to use others function blocks: IPID, RA_PID
Ps: Sorry about my poor english, hope you understand
I've been trying to tune my PLC, a AB micro 820, for such a long time and I haven't yet noticed what I've done wrong.
I have a water level system consisted of two tanks, where one of then is only to storage the water that will be send to the other tank using a pump. The pump is controle through a frequency inverter and the inverter receives signal from the controller. The water level is measured using a ultrasonic sensor. The output flow of the tank is constant.
I've applied a step in the system and through its answer i was able to identify the transfer function of the plant.
I than, tried to apply Ziegler-Nichols to tune the system, but it didn't work. The controller output was binary, since the system is limited in the range 0-7v. I concluded that this happened because the gains were values too elevated.
My next move was trying to tune it using Mathlab, I used the Autotuner app, and noticed the it works really good for P and PI tuning the only thing i had to do is divide 1 by I parameter, but when i tried to apply PD or PID it doesn't worked. I've also realized that the PI part of the controller have the following transfer function Kp(1 + 1/(I*s))
I tried to find the block diagram or the transfer function of the PID Function Block but i haven't found anything.
Have you ever used a AB Micro800 series plc and used this PID function block?
Have you succeed tuning it?
Do you know how the derivative part of this function block works?
Do you have any idea of what could i do?
Do have a ladder block logic so it wouldn't be necessary using AB Function Blocks?
Ps: I've also tried to use others function blocks: IPID, RA_PID
Ps: Sorry about my poor english, hope you understand