3/8/2022 10:11:54 AM Module: 310304cB Version: 21 Page: 6 Comment: Page 6 reads "You can use some to analyze both gases and and liquids." should read "You can use some to analyze both gases and liquids." Although I am using an older version of the booklet so maybe it was already edited out. Status: Implemented
6/21/2021 1:10:43 PM Module: 310304cC Version: 21 Page: 8 Comment: Figure 3, point A is labeled as "At-line Zirconium Oxide Oxygen Analyzer". The text before the figure refer to it as at-line catalytic combustion analyzer. There is discrepancy between text and figure for point A. Also, was there supposed to be a point B for one of these analyzers? Status: Implemented
6/21/2021 1:06:21 PM Module: 310304cB Version: 21 Page: 27 Comment: Figure 15: there are two different shades for right and left half of the ring. There does not seems to be any real reason behind this and can cause confusion. Also there are lines splitting the sample inlet and sample outlet. In reality there is no line, as it is a hollow ring. Suggest to remove the lines splitting the inlet and outlet shades for Figure 15 to avoid confusion and just leave the arrows and the circle for magnet. Status: Implemented
6/21/2021 12:06:07 PM Module: 310304bB Version: 21 Page: Comment: page 7: temperature of 294.26 is mentioned as std. This can cause confusion as typical standards are 60F for API , 0deg C for STP. My suggestion is to rephrase and explain that the rotameters are typically calibrated and used at room temp which is 294.26K and pressure of 101.3kPaa. page 19: Figure 14, the arrow on the bottom left line should be changed to from to show the sample if extracted from that line. pages 38 and 39: in the steps 2, 3, 4 and 5 for fill and empty, pigtail valve is mentioned. It is not clear what this pig tail valve is as there is no mention of it in Fig 34 on page 38. Could you please look into clarifying what it is and update the text and/ or Fig 34 (if needed) Thanks! Status: Implemented
6/21/2021 11:21:16 AM Module: 310304a Version: 21 Page: 42 Comment: page 42: (1) There is no rule of thumb or info regarding concentration of span gas. (2) Discrepancy in concentration of H2 in text (specified as 4.91%) and Fig 37 (4.9%) which need to be corrected. Status: Implemented
6/21/2021 11:13:28 AM Module: 310304f Version: 21 Page: 11 Comment: The equations for displacement, velocity, acceleration, peak displacement, peak velocity and peak acceleration contain errors. 2f or 2ft should be changed to 2. pi .f Status: Implemented
4/8/2021 9:18:34 AM Module: 310305dA Version: 21 Page: 5 Comment: Remove digital Implementation section on the top half of the page. Digital controller's use the scan time in the calculation and do not require any additional filtering. Noisy signals in general should not be filtered any differently than analog devices. Any filtering that does occur should be for known periodic noise that is in the environment such as electrical 60Hz noise. For other noise types it is better to change the transmitter to a less noisy version such as from orifice to coriolis and/or adjust your tuning to minimize noise effect by reducing gain (generally to 0.2 or 0.3 as this cuts the noise down to 20 or 30% in amplitude) and using primarily reset to provide control. (Note that reset is the only control mode that noise has little impact on) Status: Declined
4/8/2021 8:48:17 AM Module: 310305dB Version: 21 Page: Comment: Remove all references to controller scan time and its effect on deadtime. The problem is that yes the controller adds deadtime to the process however we are using the controller to find the deadtime and therefore the extra deadtime is already added to the measured deadtime. Now if we used another device to find the deadtime then we would subtract that devices deadtime from the found deadtime to get the processes actual deadtime and then we would add the controllers deadtime to use the control loops deadtime. Best to ignore this small issue as it will confuse the learner and 99% of the time we are using the controller to find the deadtime so it cancels out. Status: Implemented
3/26/2021 9:24:51 AM Module: 310305dB Version: 21 Page: 12 Comment: The bottom note is misleading. The phase margin is the amount of phase lag that can be added before the system becomes unstable. So it is more how much lag can be added not how much it has. Status: Implemented
3/26/2021 9:11:21 AM Module: 310305dB Version: 21 Page: 6 Comment: Remove the last sentence on the page as a runaway process is a higher order integrating process (Two or more integrating processes on to of each other). A further line should be added as this ILM does not equip the Technician to tune these types of processes. Runaway processes are very difficult to tune and sometimes have a very small range of stable controller settings. It is best to leave these processes alone as the process can become unstable with gain too high or too low. They do not react well to Reset and will generally require Rate to be stable. Status: Implemented
3/18/2021 8:13:42 AM Module: 310305f Version: 21 Page: 13 Comment: For reset wind up this will occur any time that the selector is placed between the valve and the controller. This does not only happen with override control but also with limit control and the incorrect auctioneering with multiple controllers (If this is moved to override it fixes this problem). Wording is incorrect in the first para and wind up needs to be prevented when the controller is not driving the valve as the case when the limit protection is preventing the valve from closing the reset needs to be held at the limit not 0 or 100% so that it can open the valve immediately when demand goes up. Status: Implemented
3/18/2021 8:02:54 AM Module: 310301a Version: 21 Page: 12 Comment: On point 1 the high selector is because we want to select the valve with the highest throughput. If the valves were FO then we would use a low select (If we were optimizing a cooling system). Reword so that it is clear we are selecting the highest flow. Status: Implemented
3/18/2021 7:59:09 AM Module: 310305f Version: 21 Page: 11 Comment: Replace symbol with H selector. Add sentence that if the valve was FO the a L select would be required with a 95%. Status: Declined
3/18/2021 7:55:27 AM Module: 310305f Version: 21 Page: 44990 Comment: First off the text only indicates that a high select can be used when low and average selects can also be used for Auctioneering. Note that the use of multiple controllers in not auctioneering. This is override control and needs to be removed from here. ( for it to work with multiple controllers you must use always a low select and you have issues with reset wind up etc... ie the same as auctioneering) Status: Implemented
3/18/2021 7:42:47 AM Module: 310305f Version: 21 Page: 44960 Comment: Average selector is missing which is used in auctioneering. Note that the high limit selector is a not high symbol and represents in essence a low select that combined with the extra H on the side which are commonly used in the box and not the < and > symbols make this section extra confusing. I would change the < and not> to L and > and not< to H in the boxes and rewrite removing the current extra H and L from the diagrams and text. Status: Declined
3/17/2021 2:49:33 PM Module: 310305e Version: 21 Page: 21 Comment: Initialized Manual mode was removed earlier in the ILM. Do we still want it here or does it need to be reworked or do we want to add it back in earlier in the ILM? Status: Implemented
3/17/2021 2:44:00 PM Module: 310305e Version: 21 Page: Comment: Remove Pneumatic controllers section and change Digital controllers heading to something new. Note that External feedback is a common feature on Pneumatic controllers also not all digital controllers have this feature, so this needs fixing. Status: Implemented
3/17/2021 2:40:13 PM Module: 310305e Version: 21 Page: 14 Comment: As i-man was removed from the module the primary controller only has two modes now and the first sentence must be fixed (or return the i-man). Status: Implemented
3/17/2021 2:29:14 PM Module: 310305cB Version: 21 Page: Comment: The students get confused here as the para that start Figure 20 shows..... Is part of an example that has a disturbance that follows the PV and CO and has three zones. Then at the end of page 21 add an example of a bullet tank level control which only follows PV and not CO. To solve this one we tune it the slowest acceptable at 50% and then find the level where the control gets to aggressive and start a new region again with the slowest acceptable tuning at the start of the new region. So Tune at 50% then if 80%/20% is too fast retune at these points and test at the max and min levels to see if you need two more regions. Status: Declined
3/17/2021 2:16:56 PM Module: 310305cB Version: 21 Page: 17 Comment: In note at top of page add that the nonlinearity must follow the CO. Remove figure 19 with the para before and after as this is not part of non-linearity objective. Status: Implemented
3/17/2021 2:13:48 PM Module: 310305cB Version: 21 Page: 14 Comment: Add to bottom of page 14. It is recommended that the characterizer be located in the controller so that the controller shows the actual valve position sent to the valve. Note that a characterizer is only able to correct for disturbances that follow the CO. If the disturbance does not follow the CO another method must be used. Status: Implemented
3/17/2021 2:03:25 PM Module: 310305cB Version: 21 Page: 45273 Comment: Note that valve selection will potentially improve linearity. So replace page 12 second last para sentence one "which results in a more linear loop." Remove the last para on page 12 as it is incorrect. It is correct to engineer valve to operate with small changing pressure drops across them. The plant does not want to pay to have oversized pumps running full out to provide fixed pressure drops across all valves. Remove para at top of 13 or reword. What is important is that the pressure drop, valve trim and pump curve produce a near linear response in the operating range. Last para on 13 remove "or to correct a mechanical sizing issue in others". Note that nonlinearity due to oversized valves is an issue in aging plants. This may be corrected by reducing the port size of the trim to improve the range of valve stem motion and thus linearity. Status: Implemented
3/17/2021 11:47:50 AM Module: 310305b Version: 21 Page: Comment: For comments were made to the module in error they should be for 310305cA. 3/17/21 11:08:04 3/17/21 11:11:07 3/17/21 11:12:37 3/17/21 11:12:57 Please move them to the other module sorry. Status: Declined
3/17/2021 10:16:32 AM Module: 310305b Version: 21 Page: 21 Comment: As with the first-order the dynamic gain of Integral heads to 0 with high frequencies here the phase shift is set at 90 but the Reset reaches 90 degrees at high frequencies so again will not go unstable unless other dynamics are present. It will oscillate but will die down. Status: Implemented
3/17/2021 10:11:20 AM Module: 310305b Version: 21 Page: 14 Comment: Remove text at top of page before the note. This is why the diagram on 13 is in error the writer added non-linearity to the problem this is not appropriate at this time and an extra source of confusion. Status: Implemented
3/17/2021 10:08:34 AM Module: 310305b Version: 21 Page: Comment: Note that the addition of reset to a pure first order system will not make it go unstable as shown in Figure 15 and the text on the bottom of 14. As the dynamic gain of the plant approaches 0 as the phase lag goes to 90. So you will get oscillations but they will die out. However the addition of a digital controller with deadtime can push it to instability as shown Status: Implemented
3/17/2021 9:59:31 AM Module: 310305b Version: 21 Page: 13 Comment: Figure 13 C the overshoot will be smaller for a pure first-order system with a controller gain of 10 then it had with a gain of 2. For this to occur as shown indicates the presence of a higher order or deadtime. My concern is that it appears that the stability of the loop is affected by the higher gain which it is not if it is pure first-order. Status: Implemented
3/17/2021 9:28:24 AM Module: 310305b Version: 21 Page: 15 Comment: "First" spelling error on tittle. Status: Implemented
3/3/2021 2:53:43 PM Module: 310305dA Version: 21 Page: 12 Comment: Figure 12 the arrow with the CO on the chart is not correct as the CO is not the Bias if there is error. As the example has PV<>SP. Remove the CO from the picture and you are okay. If you want to add CO then you need to ramp up the CO in a curve faster than the Bias at time T0 and then sit at 100% until some time between t3 and t4 when the proportional will bring the CO below 100% before the Bias drops below 100%. Status: Implemented
3/3/2021 2:43:51 PM Module: 310305dA Version: 21 Page: 11 Comment: Picture B in figure 11 is incorrect unless the gain of the controller is set to about 0.2. Note that the DG filter removes the noise amplification due to the D but it does not reduce the noise as P passes this through. Note that with a gain of 1 the CO will have the same amplitude of noise as the PV. The statement is correct but the picture miss represents what is happening. Status: Implemented
3/3/2021 2:38:00 PM Module: 310305dA Version: 21 Page: 5 Comment: I am generally opposed to any use of filtering on controller inputs other than to reject electrical noise. The Digital Implementation section on the top of the page should be removed. Analog input modules do not introduce noise or require filtering and this is incorrect they actually provide a bit of filtering of the data unfortunately by the nature of their operation and loss of data. Filtering unfortunately make this problem even worse. Status: Implemented
3/3/2021 2:29:38 PM Module: 310305dA Version: 21 Page: 3 Comment: Figure 1 is incorrect as it is a ID controller and the line from the output of the P to the summing block has been omitted. Status: Implemented
3/3/2021 2:16:59 PM Module: 310305dB Version: 21 Page: 39 Comment: The last paragraph on the page is incorrect. The real issue is that the dynamic loop gain of a flow loop is very close to the static gain and as such the loop gain must be less than one to prevent instability. Note that low controller gains with a high process gain will have small offset. Now as the plant gain for a flow loop should be close to one if the equipment is sized correctly the answer is partially correct. Better to say that as the loop gain is less than one, offset is a problem.... Now as flow loops are noisy and proportional passes that noise through to the valve I would prefer. As flow loops are very noisy it is recommended to not use derivative which amplifies the noise and a small gain to reduce the noise (a gain of larger than 1 will amplify the noise and a gain of 1/2 with cut it in half). The low gain requires the use of integral to return the loop to setpoint. (note that integral is the only mode that will smooth out the noise) Status: Declined
3/3/2021 1:42:58 PM Module: 310305dB Version: 21 Page: 23 Comment: This equation for Tc confuses many of the students rewrite that Tc is equal to Lambda times the larger of T1 and TD. Status: Implemented
3/3/2021 1:40:23 PM Module: 310305dB Version: 21 Page: Comment: Relay-Oscillation Tuning Too much information Tradesmen do not manually do this method as it is used by computers to suggest tuning which can be more than just ZN. Tradesmen need to know when and how to use this method. Status: Implemented
6/24/2020 9:45:29 AM Module: 310304bA Version: 21 Page: Comment: Page 31: Paragraph two, above figure 34: it is stated that "Packed tube absorbers also use silica gel or molecular sieves to trap water by absorption on their outer surfaces." Removal of interfering gases by using silica gel or molecular sieves happens by adsorption (NOT absorption). So the sentence should be changed to adsorbers, and adsorption. Page 40: Paragraph two, above figure 45, second line: it is stated "measure 02 as long as temperatures..." this is referring to oxygen gas measurement. The current text has number zero 0, instead of letter O for oxygen, so it should be corrected. Status: Implemented
1/22/2020 11:09:15 AM Module: 310302a Version: 1.1 Page: Comment: It seems to me technology has evolved to the point that it is difficult to find an manual ranging meter that we would use in our trade. Most newer devices like the fluke 725 have set resolutions, and we normally measure 30v or less. For example the 725 when reading a "aa" battery will display 1.234v, not 1.2345 and its resolution is .001 regardless of the range up to it's 30v max. So I am questioning the relevance of the whole 4 1/2 digit exercise. Opinions would be appreciated.... Status: Declined
11/21/2019 7:22:29 PM Module: 310302f Version: 1 Page: Comment: Page 10 states that to improve sensitivity move the probe closer to vessel wall. Question three is incorrect in saying the answer is true. Moving the probe further from vessel wall should decrease sensitivity which would make question three false. Status: Implemented
1/1/2019 12:00:00 AM Module: 310305e Version: 1.1 Page: 6 Comment: The information on valve positioners as an example of a cascade loop if overkill. Positioners are a common occurance and have very little to no tuning ability. I reccommend reducing the information that starts on page 6 and ends at the bottom of page 7. Mention that as "An example, a positioner in a control loop is a simplified cascade control scheme. The positioner is high gain P-Only controller that has its setpoint set by the output of the main controller." Keep figure 5. Status: Implemented
1/1/2019 12:00:00 AM Module: 310302a Version: 1.1 Page: 26 Comment: This is a % of reading question, there for the answer should be: .005 x 144.3= 0.7215 Status: Implemented
1/1/2019 12:00:00 AM Module: 310302a Version: 1.1 Page: 28 Comment: question 13. answer should be 0.0005 not 0.0004 (0.02/100)1 + 3(0.0001)= 0.0005 Status: Implemented
1/1/2019 12:00:00 AM Module: 310301a Version: 1 Page: 24 Comment: The solution for the R Loop max is shown as 525 ohms. The correct value is 575 ohms. Status: Implemented
1/1/2019 12:00:00 AM Module: 310302o Version: 2 Page: 23 Comment: Answer key is incorrect. If keeping this question the answer should be True; Gases are less viscous than liquids, so slippage is more of a problem. Status: Declined
1/1/2019 12:00:00 AM Module: 310304dB Version: 2 Page: 30 Comment: Before the equation for L25, the sentence ends (C25). (C25) should be changed to (L25). Status: Implemented
1/1/2019 12:00:00 AM Module: 310304dB Version: 2 Page: 39 Comment: Before the equation for L25, the sentence ends (C25). (C25) should be changed to (L25). (The previous feedback submission had the wrong page number!) Status: Implemented
1/1/2019 12:00:00 AM Module: 310304e Version: 2 Page: 14 Comment: Table 4- for LPG applications, it is mentioned that for LPGs with vapour pressures up to 111.6 MPa (225psig). 111.6MPa is not 225psig. If you convert 111.6 MPa to psi, you will obtain 16186psi!!! I do not have access to ASTM D 1267-89 to verify what the vapour pressure is. Status: Implemented
1/1/2019 12:00:00 AM Module: 310304e Version: 2 Page: 30 Comment: Step 4 of operation for Vibrating Probe Viscometer need to be modified. Signal is inversely proportional to viscosity. See figure 1.71ac of Liptak (Fifth Edition, Volume II, Analysis and Analyzers) Status: Implemented
1/1/2019 12:00:00 AM Module: 310305a Version: 1 Page: 18 Comment: Figure 16: FIC-101 should be changed to FIC-102. OR FT-101 needs to be changed to FT-101 to match each other Status: Implemented
1/1/2019 12:00:00 AM Module: 310301a Version: 1.1 Page: 29 Comment: last sentence, last paragraph. Reads: A proportional controller has one tuning parameter, which is the proportional gain (Kc), and a bias setting. Should read: A proportional controller has two tuning parameters, which is the proportional gain (Kc), and a bias setting. Status: Declined