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Old January 24th, 2023, 08:49 AM   #196
drbitboy
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Another typo at Subroutine 50 Test Pressure, Rung 5: high/low tolerance tests are reversed?
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Old January 24th, 2023, 09:03 AM   #197
drbitboy
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Subroutine 30 Discrete Valves, Rung 2, Compare of DS1 Sequence Step to 60 (Test Pressure Hold) should be <, not ≤, because the pump should not be available to restore the test part pressure if it drops.

By the same reasoning, in Subroutine 99 Outmap, Rungs 6 and 7 should write 0.0 to the I/P transducer during step 60, the ≤ 60 on Rung 6 should be < 60, and the > 60 on Rung 7 should be ≥ 60.
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Brian T. Carcich
i) Take care of the bits, and the bytes will take care of themselves.
ii) There is no software problem that cannot be solved with another layer of indirection.
iii) Measurement is hard.
iv) I solemnly swear that I am up to no good
v) I probably have the highest ratio of forum posts to actual applications in the field (∞).
vi) Hakuna matata.
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Old January 24th, 2023, 09:48 AM   #198
parky
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Regarding slowly increasing the pressure the pump will not run at probably 6-7 ma (assume 10 psi, so I suggest when you start the pump on a oneshot (perhaps an extra step you have plenty spare as it appears that all posts so far are keeping the steps of 10) for example if step 10 was to start the pump, from 0 (Idle) move 5 or what ever into the sequence step number, move say 7 ma (min pump start air pressure) then move 10 into the seq register this in itself is a oneshot so then you have a starting air pressure rather than starting at 0 & the pump will not run until the I/P (Current to pressure) (yes that is what it is called not a transducer that is ambiguous as it also refers to a signal back (analog input)rather than analog output).
See pic on extra step to pre-load (you may have to change the step number to fit in what others or you have done).
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Old January 24th, 2023, 12:53 PM   #199
drbitboy
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Another bug in Subroutine 20 States, I think; see the attached image.
Untitled.png
What started me thinking about this is, after the NO Contact C2 HMI_PB_Cycle_Stop on Rung 3, the NC Contact C2 HMI_PB_Cycle_Stop on Rung 4, which is not necessary:
  • If C2 is 1 on a scan, then Rung 3 will trigger, which will prevent Rung 4 from triggering even if the NC C2 is not there.
  • So the only way Rung 4 can trigger is if C2 is 0 in the first place, plus all the other contacts on Rung 4, so the NC C2 is redundant.
Also, this is the only reference to C1 HMI_PB_Cycle_Start in the entire program, so pressing the HMI start button is the only way to affect anything, and all it does is prevent the 10=>20 transition. Then there is the issue whether the HMI sets and clears the button's bits, or if those bits are set-and-forget.

So maybe that is supposed to be C1 in Rung 3?

P.S. I assume each of those bits is "active" (i.e. to start or to stop) when its value is 1.

Or maybe this is what was intended: pressing HMI Stop transitions to State 10 (Idle) from any state; pressing HMI Stopm, while both (i) in State Idle AND (ii) test part is depressured, transitions to State 20 Ready.
Untitled2.png
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Brian T. Carcich
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iv) I solemnly swear that I am up to no good
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vi) Hakuna matata.
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Old January 24th, 2023, 04:39 PM   #200
drbitboy
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This might work. I wonder if there is a conversion app from Click to DoMore; this should be straightforward to simulate.


[Edited: fixed a typo in the program]
Attached Files
File Type: pdf HPTv004drbitboy.pdf (1.13 MB, 0 views)
File Type: zip Hydrostatic Pressure Tester v004_drbitboy.zip (14.8 KB, 1 views)
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Brian T. Carcich
i) Take care of the bits, and the bytes will take care of themselves.
ii) There is no software problem that cannot be solved with another layer of indirection.
iii) Measurement is hard.
iv) I solemnly swear that I am up to no good
v) I probably have the highest ratio of forum posts to actual applications in the field (∞).
vi) Hakuna matata.

Last edited by drbitboy; January 24th, 2023 at 04:52 PM.
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Old January 24th, 2023, 05:26 PM   #201
drbitboy
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Here are some of the key pieces of the algorithm that sets the air pressure regulator setpoint. At its core it does summat similar to what the human operator seems to be doing:
  • initially turn "knob" most of the way to a fixed value that should bring the system nearly to the setpoint
    • With the known pump pressure ratio, the Click can do this in one go
    • This is State 20 Start Pump
    • Transition to next state at 10psi
  • Leave knob at initial fixed value, wait for pressure to settle
    • it should settle a bit below the setpoint
    • This is State 30 Pump to initial stall
    • Transition to next state when settled
      • current "settled" criterion is empirical and untested
  • Sneak up on setpoint from there
    • "Small moves, Ellie, small moves" - tweak "knob" by ~1psi
    • compare feedback from pressure sensor to setpoint
      • stop if all sampled pressures for a full second are above the setpoint
    • repeat at 1Hz
    • This is State 40 Pump until test pressure
Not shown are the 1-second group sampling metrics, used to determine "settled" and "above setpoint," a but they are simple.
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Brian T. Carcich
i) Take care of the bits, and the bytes will take care of themselves.
ii) There is no software problem that cannot be solved with another layer of indirection.
iii) Measurement is hard.
iv) I solemnly swear that I am up to no good
v) I probably have the highest ratio of forum posts to actual applications in the field (∞).
vi) Hakuna matata.
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Old January 25th, 2023, 07:25 PM   #202
drbitboy
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Update: I forgot to attach the image to that last post; here it is below.


Quote:
Originally Posted by drbitboy View Post
here are some of the key pieces of the algorithm that sets the air pressure regulator setpoint. At its core it does summat similar to what the human operator seems to be doing:
  • initially turn "knob" most of the way to a fixed value that should bring the system nearly to the setpoint
    • with the known pump pressure ratio, the click can do this in one go
    • this is state 20 start pump
    • transition to next state at 10psi
  • leave knob at initial fixed value, wait for pressure to settle
    • it should settle a bit below the setpoint
    • this is state 30 pump to initial stall
    • transition to next state when settled
      • current "settled" criterion is empirical and untested
  • sneak up on setpoint from there
    • "small moves, ellie, small moves" - tweak "knob" by ~1psi
    • compare feedback from pressure sensor to setpoint
      • stop if all sampled pressures for a full second are above the setpoint
    • repeat at 1hz
    • this is state 40 pump until test pressure
not shown are the 1-second group sampling metrics, used to determine "settled" and "above setpoint," a but they are simple.
Untitled.png
__________________
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Brian T. Carcich
i) Take care of the bits, and the bytes will take care of themselves.
ii) There is no software problem that cannot be solved with another layer of indirection.
iii) Measurement is hard.
iv) I solemnly swear that I am up to no good
v) I probably have the highest ratio of forum posts to actual applications in the field (∞).
vi) Hakuna matata.
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