Saturday, August 11, 2012 8:25:03 PM
Chapter 1: My Story on Changing Settings of a Control System.
Response to remarks made by Tom Veale in http://investorshub.advfn.com/boards/read_msg.aspx?message_id=78405650
Good to hear from The Old Man(TOM)once in a while
I remember when I first got in contact with you on this Forum we had a lively discussion on Control Systems in general and that an AIM in fact is control system for investing money in a particular way. . .and a feature of control systems is that they have a number of "knobs" on them that can be rotated left and right by an operator. . .we never had any discussion on why these "dials" were there. . . we both knew why they are there: they are to be adjusted in response to system changes and external influences. I may even have told you about the time I was in the Digester Control Room of the Grande Prairie Pulp Mill in Alberta. The operators had a great problem with the Chip Chute Liquor Level. . .It is the Mixing vessel for wood chips and liquor mixing in order to pump the mixture at high pressure into a huge Kamyr Digester of about 50 m high. . . The CC either overflowed or the pump went dry any time they wanted to “run the mill a bit faster” than it was designed for (750 Tons/day of pulp). Proctor & Gamble wanted to run the mill faster so they set op a De-bottlenecking Program: This was the Instruction to all the operators: “Make everything run faster and when things go haywire and break down. . fix the bloody haywire and keep making the mill run faster again until Hell Freezes Over. . .I was the luckiest engineer on earth, almost fresh out of school, to be assigned to that mill . . .It was not my function to be in that Control Room at all. . .I just roamed the mill now ant then out of curiosity. . .Each time the Chip Chute (CC) System went off-line sirens went of. . .this was normal MO there. . .all the operators were turning knobs left, right and back on all the knobs they could find and I thought: “Hey this is a great place to be. . .things are happening here!!!” The Chief Operator. . .a young guy of I bet no older that 28 or so, explained to me: “This Mill is designed for 750 TPD and we got it running at 900 now but we have reached a bottleneck: the level of the CC can not be controlled and the Chief Instrumentation Man says the Level Controller can not handle it. . .look at this red level trace on the chart. . .it looks like an elevation profile of the Rocky Mountains just to the east of us here. . .we can not fix it”. I asked him: “Would it be OK if I try to adjust the settings to tune the controller a bit?”. . .the guy said: “ No problem. . .you could not make it worse that it is. . .The Chief Instrumentation Man has tried it too but he could not get the level stabalised”. So, I went at work on this PID Level controller. . .I was a greenhorn on this. . .it was the first Level Controller that I had ever faced outside of the university! . .So, I looked at the knobs, my fingers were itching to turn something. . .Knobs are made for Turning, and that’s what I will make them do, I thought . . .(Nancy Sinatra was standing behind me. . I swear it. . . urging me onwards. . .her boots were drumming their beat. . .in my head).
”Hey Man look at this”, I said, “The D-knob stands at zero. That’s not good at all. . .at zero it does noting! D stand for Derivative!” . . .The Chief Operator (CO) came looking and said: “I’ll be damned! What the hell is a derivative for???? The Chief Instrument Man has set it probably at 0. . . he has fiddled many times with this controller. . what does it do?”. . .I saw the writing on the wall. . .these people missed a bit of control theory, so I began to see the possibilities for me to let Nancy Sinatra push me further. . . An entire pulp mill De-bottlenecking Project would fall into my hands if I had my way. . .they obviously depended on me . . .So I did what came natural to me and explained: ”A derivative feature on a controller is a “rate of change” sensor for a variable in a process . . .in this case it is for measuring the time rate of change of the fluid level in the Chip Chute Level. . .most people would call it the “velocity” at which the fluid level rises or falls. Thwe controller would adapt the control valve opening time-shift to make it open more or less at the right time”. . .
”You got to be kidding me!” said the CO. . “how do you know all that?”. . .At D=0 it does probably not measure anything and do noting!”. . .The CO was obvious not an idiot. . .that was promising. . . So I told him that I will try a few things with different setting on the PID-controller and I did so. . . and in a short time the red line on the controller chart was already less “jittery” than before. The CO said: “We were told not to touch these knobs, but I see that you have already achieved a better level control setting. Obviously the fluid velocity changes in the CC are great and the Control System does not react fast enough to correct the flow if it is wrong. . .I got to leave now, my shift is ending. . .do what you can. . . you have my blessing!”. . .and he left. . . I felt like King Salomon. . .I had the Power to make things better. . .or to make a bloody mess of it. . . I had a multi million Dollar Kamyr Digester in my hands! It might as well have been The World . . . I felt like a Little God. . after all, I was a greenhorn facing to attack my first Level Controller in Real Life. . and I went to work! . . .A few times the bells started ringing when the P-knob was turned to much and the system went OUT. . .it was not en emotional reaction. . .it was simple a trial and error level control experiment. . .getting the fingerspitzengefühl of it in my hands. . .No problem. . .the boys at the other knobs knew how to get the Digestor on line again. . .everything was normal. . .this happened routinely every time when they turned the knobs.
I adjusted the PID-settings in a great many variety of relative positions and got to a situation at which the red liquid-level-trace jittery had been reduced to a 3 cm narrow range on a scale of +/- 5 cm chart. . .The D-knob stood at some non-zero position. Then, I started fine-tuning and got to the point the red up-down trace had about a 2 cm bandwidth and I went home. . . it was midnight. The next day I went to visit and the CO was as happy as a pig in shit: “I am amazed at what you to have achieved last night. . .You must have magical power in you hands. . .we are running at 950 TPD and all is well and the liquor level is stable, but at 975 TPD the system knocks itself out again. . .we want to go to at least 1000 TPD now. I have given a Work Order to install a bigger control valve. . .the 6” Bal Valve in the feed line will be replaced by a 10" Fischer Ball Valve in a few days".
I did a bit more fine-tuning but could not get the trace jitter much narrower than the 2cm range. . .I thought: “I have to check out that 6”ball valve . . .A 10” valve in a 10” pipeline is going to be a problem. . . I think.
***************
When we step in a cockpit of an aircraft there are a few knobs to be seen. . .If they were there just for the fun of it and not be connected to anything, then we could conclude that that aircraft is a sophisticated autonomous machine that could fly itself under any weather circumstance, and get to the instructed destination without the pilot doing anything at all. . . .all the knobs would be there only to entertain the Pseudo Pilot so that he would not become bored wile being there . . and not only that the pseudo pilot would only be there to make the passengers feel that they were in safe hands. . .An aircraft without “control knobs” to turn during the flight is an absolute impossibility. . . .ever. . .it must have an active control system(CS) in order to adapt to weather changes.
Any discussion on the proposition of not adjusting the settings on a control system(CS) is completely idiotic and therefore pointless. That is so for a CS in a chemical factory and that is so for an AIM Investment system. If CS knobs would have to be fixed and left alone then anything more that is said about it are wasted words. . .and in that light you would have to conclude that everything that has been discussed on AIM on this Forum, since its inception, on changing the values of a Hold Zone, the SAFE, the Update Fraction other than 0,5 of the PC, and all the other AIM-settings and adaptations that have been suggested to be useful, has been a waste of time. . . and current discussions on the subject would also be just as pointless. . . it would have been meaningless chatter that had no purpose other than to fill the Forum pages with nonsense and to spend time doing so because there was noting more useful to do...If that is the collective consensus of the readers of the AIM Forum in regards to AIM-setting changes then AIM Users might better join a Knitting Club. . .at least they would have something useful to do then.
Why talk about AIM-settings ever, if they are not to be changed? I will answer this with the ending of my Grand Prairie Chip Chute Control System Story.
Continued in Section 2
Response to remarks made by Tom Veale in http://investorshub.advfn.com/boards/read_msg.aspx?message_id=78405650
Good to hear from The Old Man(TOM)once in a while
I remember when I first got in contact with you on this Forum we had a lively discussion on Control Systems in general and that an AIM in fact is control system for investing money in a particular way. . .and a feature of control systems is that they have a number of "knobs" on them that can be rotated left and right by an operator. . .we never had any discussion on why these "dials" were there. . . we both knew why they are there: they are to be adjusted in response to system changes and external influences. I may even have told you about the time I was in the Digester Control Room of the Grande Prairie Pulp Mill in Alberta. The operators had a great problem with the Chip Chute Liquor Level. . .It is the Mixing vessel for wood chips and liquor mixing in order to pump the mixture at high pressure into a huge Kamyr Digester of about 50 m high. . . The CC either overflowed or the pump went dry any time they wanted to “run the mill a bit faster” than it was designed for (750 Tons/day of pulp). Proctor & Gamble wanted to run the mill faster so they set op a De-bottlenecking Program: This was the Instruction to all the operators: “Make everything run faster and when things go haywire and break down. . fix the bloody haywire and keep making the mill run faster again until Hell Freezes Over. . .I was the luckiest engineer on earth, almost fresh out of school, to be assigned to that mill . . .It was not my function to be in that Control Room at all. . .I just roamed the mill now ant then out of curiosity. . .Each time the Chip Chute (CC) System went off-line sirens went of. . .this was normal MO there. . .all the operators were turning knobs left, right and back on all the knobs they could find and I thought: “Hey this is a great place to be. . .things are happening here!!!” The Chief Operator. . .a young guy of I bet no older that 28 or so, explained to me: “This Mill is designed for 750 TPD and we got it running at 900 now but we have reached a bottleneck: the level of the CC can not be controlled and the Chief Instrumentation Man says the Level Controller can not handle it. . .look at this red level trace on the chart. . .it looks like an elevation profile of the Rocky Mountains just to the east of us here. . .we can not fix it”. I asked him: “Would it be OK if I try to adjust the settings to tune the controller a bit?”. . .the guy said: “ No problem. . .you could not make it worse that it is. . .The Chief Instrumentation Man has tried it too but he could not get the level stabalised”. So, I went at work on this PID Level controller. . .I was a greenhorn on this. . .it was the first Level Controller that I had ever faced outside of the university! . .So, I looked at the knobs, my fingers were itching to turn something. . .Knobs are made for Turning, and that’s what I will make them do, I thought . . .(Nancy Sinatra was standing behind me. . I swear it. . . urging me onwards. . .her boots were drumming their beat. . .in my head).
”Hey Man look at this”, I said, “The D-knob stands at zero. That’s not good at all. . .at zero it does noting! D stand for Derivative!” . . .The Chief Operator (CO) came looking and said: “I’ll be damned! What the hell is a derivative for???? The Chief Instrument Man has set it probably at 0. . . he has fiddled many times with this controller. . what does it do?”. . .I saw the writing on the wall. . .these people missed a bit of control theory, so I began to see the possibilities for me to let Nancy Sinatra push me further. . . An entire pulp mill De-bottlenecking Project would fall into my hands if I had my way. . .they obviously depended on me . . .So I did what came natural to me and explained: ”A derivative feature on a controller is a “rate of change” sensor for a variable in a process . . .in this case it is for measuring the time rate of change of the fluid level in the Chip Chute Level. . .most people would call it the “velocity” at which the fluid level rises or falls. Thwe controller would adapt the control valve opening time-shift to make it open more or less at the right time”. . .
”You got to be kidding me!” said the CO. . “how do you know all that?”. . .At D=0 it does probably not measure anything and do noting!”. . .The CO was obvious not an idiot. . .that was promising. . . So I told him that I will try a few things with different setting on the PID-controller and I did so. . . and in a short time the red line on the controller chart was already less “jittery” than before. The CO said: “We were told not to touch these knobs, but I see that you have already achieved a better level control setting. Obviously the fluid velocity changes in the CC are great and the Control System does not react fast enough to correct the flow if it is wrong. . .I got to leave now, my shift is ending. . .do what you can. . . you have my blessing!”. . .and he left. . . I felt like King Salomon. . .I had the Power to make things better. . .or to make a bloody mess of it. . . I had a multi million Dollar Kamyr Digester in my hands! It might as well have been The World . . . I felt like a Little God. . after all, I was a greenhorn facing to attack my first Level Controller in Real Life. . and I went to work! . . .A few times the bells started ringing when the P-knob was turned to much and the system went OUT. . .it was not en emotional reaction. . .it was simple a trial and error level control experiment. . .getting the fingerspitzengefühl of it in my hands. . .No problem. . .the boys at the other knobs knew how to get the Digestor on line again. . .everything was normal. . .this happened routinely every time when they turned the knobs.
I adjusted the PID-settings in a great many variety of relative positions and got to a situation at which the red liquid-level-trace jittery had been reduced to a 3 cm narrow range on a scale of +/- 5 cm chart. . .The D-knob stood at some non-zero position. Then, I started fine-tuning and got to the point the red up-down trace had about a 2 cm bandwidth and I went home. . . it was midnight. The next day I went to visit and the CO was as happy as a pig in shit: “I am amazed at what you to have achieved last night. . .You must have magical power in you hands. . .we are running at 950 TPD and all is well and the liquor level is stable, but at 975 TPD the system knocks itself out again. . .we want to go to at least 1000 TPD now. I have given a Work Order to install a bigger control valve. . .the 6” Bal Valve in the feed line will be replaced by a 10" Fischer Ball Valve in a few days".
I did a bit more fine-tuning but could not get the trace jitter much narrower than the 2cm range. . .I thought: “I have to check out that 6”ball valve . . .A 10” valve in a 10” pipeline is going to be a problem. . . I think.
***************
When we step in a cockpit of an aircraft there are a few knobs to be seen. . .If they were there just for the fun of it and not be connected to anything, then we could conclude that that aircraft is a sophisticated autonomous machine that could fly itself under any weather circumstance, and get to the instructed destination without the pilot doing anything at all. . . .all the knobs would be there only to entertain the Pseudo Pilot so that he would not become bored wile being there . . and not only that the pseudo pilot would only be there to make the passengers feel that they were in safe hands. . .An aircraft without “control knobs” to turn during the flight is an absolute impossibility. . . .ever. . .it must have an active control system(CS) in order to adapt to weather changes.
Any discussion on the proposition of not adjusting the settings on a control system(CS) is completely idiotic and therefore pointless. That is so for a CS in a chemical factory and that is so for an AIM Investment system. If CS knobs would have to be fixed and left alone then anything more that is said about it are wasted words. . .and in that light you would have to conclude that everything that has been discussed on AIM on this Forum, since its inception, on changing the values of a Hold Zone, the SAFE, the Update Fraction other than 0,5 of the PC, and all the other AIM-settings and adaptations that have been suggested to be useful, has been a waste of time. . . and current discussions on the subject would also be just as pointless. . . it would have been meaningless chatter that had no purpose other than to fill the Forum pages with nonsense and to spend time doing so because there was noting more useful to do...If that is the collective consensus of the readers of the AIM Forum in regards to AIM-setting changes then AIM Users might better join a Knitting Club. . .at least they would have something useful to do then.
Why talk about AIM-settings ever, if they are not to be changed? I will answer this with the ending of my Grand Prairie Chip Chute Control System Story.
Continued in Section 2
Conrad Winkelman
What is Vortex AIMing? Look for my Vortex Discussion Forum:
http://investorshub.advfn.com/boards/board.asp?board_id=1341
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