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Hello everyone, Not sure if I have the right forum, so please forgive me; but... I have a control loop to tune, and it's the first one that I've ever been in charge of.  My question is about tuning PID.  The loop I have to tune is controlling a pressure reactor to setpoints ~3000psi with a safety valve that blows around 4500 psi.  My question is what procedure you might go through to tune it safely.  I'm quite honestly a bit afraid of the high pressures and I really don't want to make anything "pop".  What also makes it tricky is that the reactor has to heat up to get to full pressure.  Without heat, the reactor will reach ~1000 psi, then it sits there for a long time and eventually the heat kicks in and the pressure can rises up very quickly. I currently have a very small gain value, something like 0.009 and an integral time of ~7sec.  I'm getting pretty good results in that the PID controller will bring the reactor up to pressure without major overshoot, but it oscillates at ~ +-100psi, which seems excessive to me. [The situation is further complicated by the material in the reactor, a slurry, which has variable density often causing pressure spikes and drops as thicker sediments blob through.  Then, valves that we are using to control appear to be only opening ~10% to maintain setpoint, meaning I only get 1/10th the resolution I would be hoping for.  Also, the valve responds quite slowly to command signal changes.  The controller will be attempting to open the valve in 0.1% increments, but it only responds at minimum to 0.4% changes in the control signal, and when it reverses directions it seems to only respond after a ~5% change in control signal.  This alone appears to cause oscillations that I don't know if a PID loop could ever get ahold of.] Anyways, aside from the obvious valve issues, is there any tips for tuning a system with this high pressure?  I need fast response, but slow buildup... (Oh yeah, I'm also having to use connected components workbench for control software.  At least the newest version of CCW seems to have a nice iPID control block; but man, I have never had to ctrl-alt-delete a program more times due to freezing while building or downloading...so frustrating...).

Hello,  I have two pressure transmitters connected to a tank. One at the top and one at the bottom. How can I calculate the level of the tank ? I know the height and Specific gravity of the materials.    Thank You  Pratik Jain

Hello Everyone... I got a project of pumping station... Need your help to fulfill client requirements through PLC logic...   #System# There are 6 pumps, every pump is Controlled by Individual VFD, and all 6 VFDs are in Communication with PLC. Output header is common for all pumps, and a Pressure Transmitter is connected at output header...   #Logic Requirements# Now when we start sequence in auto, the least run hour vfd should start first and increase the frequency slowly to maintain the pressure setpoint, now if vfd1 at 50hz and pressure is lower then the SP next vfd according to run hour should start and and increase frequency slowly, afterwords 3rd vfd according to runhour and so on untill pressure match SP, then maintain the pressure of header... If pressure increases above the setpoint, last started vfd should reduce rpm and shut down first and then second last started to shutdown and so on... And client also need enable-disbale logic, if they mark a pump disable then that pump should not start... Can you help me out and suggest anything, or provide some sample backups or documents ?

Hi Everyone..I'm having hard time to read Analog Sensor. I've try to read the manuals about expansion module, but still having hard time to understand it. My PLC is CP1E-N30DR-A connect with Expansion CP1W-MAD44 and I'm trying to connect with pressure sensor Omron E8F2-B10C that in a certain pressure will trigger to open a Digital Valve. is there something wrong with my setting for range? I do the setting in 4-20mA (0-5V) I attached my Program and Picture while running, the program is only for reading the pressure sensor. the result is  -600 to +600, is there a way to earn the actual result? I've tried Scaling and APR, But didn't understand, is there a guide/tutorial for it as well?   Cheers.. Albert TEST.cxp TEST.cxp

Hi! Allen bradley PLC RS Logix 5000 I have a problem with a SMC pressure sensor (ISE30A if I remember correctly). When I monitoring the raw data from the ananlog module, I get about -7710 value, when the smc display shows about 0. There are another SMC pressure sensors too, and if the sensors displays shows 0 then the values what I get form the analog module is about 0 too, so the others work properly. But this one don't.  I already check the wiring. I have no clue waths the problem. Any idea from anybody? Thank you for your help.

Hello   Does someone have a good way to control pressure using PID in cx-programmer? I got two pumps and one PT(4-20mA) Half the year only one pump need`s to run (about 3bar)  but in the season (i work in a fabric) two pumps need to be running (about 4bar needed) except in the night. I`m going to use HMI for adjusting the setpoint so there is no need for any clock/date for this to change itself. The question is how to get one of the pumps to shut down when the need for pressure is not so high. And get the pumps to change "main" pump sometimes so one pump is not running all the time.   Hope this was understandable