ISPSoft not working as it should

[drbitboy]

@parky has it, of course.

If you like to play code golf:

1) if we move the Y0-toY1 transition rung to after the Y1-to-Y2 transition rung, then I am pretty sure we can drop the M0 Reset instruction from the former; only the Y2-to-Y0 transition rung needs that Reset of M0.

2) the M0 tests on the last two rungs can be simple [Normally Open] instructions instead of pulse/rising-edge instructions.

 

[parky]

DR is right, actually do not need the pulse function just use the in-built pulse contact of X0,
Also another way is to use a counter, and compare i.e.
if counter = 0 then Y0 on
Counter = 1 Y1 on
Counter = 2 Y2 on
Counter = 3 reset counter
This way you do not need to set Y0 on PLC start (assuming non retentive counter).

 

[drbitboy]

Another approach that includes using the M1002 bit to determine when the system is doing the Y0-Y1-Y2 cycling, as was present in Post #1.

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N.B. the ordering of the branches in Rung 0001 is intentional and crucial for this to work.

This is an academic exercise that would be suitable for a teaching situation, where you want someone to learn boolean logic; adding comments and/or explaining how and why this works is left to the student.

In production I would go with @parky's approach because it is easier to understand and debug when diagnosing problems.

Sometimes "code golf" brings clarity, and sometimes is brings the opposite. For example, putting this much complexity into a single rung may not be worth the obfuscation, and breaking that last rung into two or even six rungs would be aesthetically worth a few more instructions.

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[drbitboy]

DR is right, actually do not need the pulse function just use the in-built pulse contact of X0,

N.B. the in-built pulse [Rising-edge triggered] contacts on X0, if used, would need to be at the start of the last three rungs, before the [Normally-open] contacts testing Y0, Y1, and Y2.

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[drbitboy]

also another way is to use a counter, ...

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or this, which has the same subtle bug (or feature, depending on your point of view):

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[drbitboy]

Here is @parky's approach, tested so I know it works, reduced by one instruction by re-ordering the last pair of rungs:

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And here is a slight modification, dropping another three instructions by eliminating the need both for the first-pass code and for clearing the one-shot mid-program:

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ISPSOFT's Rising-edge trigger instruction would drop another two instructions.

An SQO instruction could make things even tighter, but I don't think ISPSOFT has that.

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[drbitboy]

Here's four instructions that can do the job:

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The last rung is for display only; ISPSOFT may not have equivalent instructions.

 

[EVentomar]

I looked at OP's original images again, and something does not make sense; see below.

View attachment 61870​

I was actually making a bigger program and not working. So I made this little one for testing my assumptions. And by this time my mind completely burnt out. I was trying everything I the printscreen end up going this way

 

[drbitboy]

I was actually making a bigger program and not working. So I made this little one for testing my assumptions. And by this time my mind completely burnt out. I was trying everything I the printscreen end up going this way

Ah, we've all been there and done that. Testing assumptions with little programs is an excellent approach to development though, so well done!

Anyway, use @parky's solution, with [Rising* edge-triggered contacts] on the button to the left of (i.e. before) the Normally-open contacts on M1002. All of my approaches are just for fun.

* or Falling, if X0 is wired that way.

 

[2rlp]

EVentomar, ISPSoft is a cumbersome software to use. An easier way to program Delta PLCs would be using WPLSoft.


You can check out the pdf attached

 

[drbitboy]

Here is the best I have come up with so far from both aesthetic and readable/understandable standpoints: it uses an amalgamation of what I assume are the well-known [Start/Stop] and [State Coil/Fault Coil] patterns* for both Y2 and Y1, minimizing what need be sussed, and a trivial if-no-other-output-is-1 shortcut for Y0. X0ONS is the one-shot pulse that would be controlled via the output of a [Rising edge-triggered contact] instruction in ISPSoft. Reversing the order of the rungs, i.e. Y2 before Y1 before Y0, is again critical here to avoid the wonkiness of the algorithm in Post #1. This is like a three-way version of a flip-flop circuit; I wonder if something is possible similar to the difference between two-switch vs. three-switch lighting circuits.

* cf. here and here

It is functionally similar to @parky's canonical model, which is still probably closest to the cleanest possible, with seal-ins replacing the Set/Reset pattern, but without the (awkward?) mid-scan reset of the one-shot; Set/Reset can also sometimes be problematic.

I could drop the instruction count by two if I hung the last three rungs off of a single XIC/NO M1002, but I think the aesthetics are better this way.

N.B. I still think X0 may need a debounce.

I know I am likely flogging a dead horse as far as OP is concerned, but IMNSHO clean code is never a vain pursuit.

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[parky]

@DR, Lol, you certainly know how to clean things up, how about this one, only two rungs using bit shift, only caveat is if the outputs are driven directly then need "Y3" that is not in the program but I suppose could use memory bits to drive the coils but that would require extra code.

 

[parky]

I have DR's bug now, got round the extra Y output just one extra rung & 1 extra contact in the bit shift.

 

[drbitboy]

@parky: sweet, I am green with envy!

I did summat similar in Post #22, AB can pass a bit into the BSL, so that saves a few instructions, but also leaves the Y2 bit to shift its way, like a stale f@rt, through the following 13 discrete output bis, which would not work, so as you noted it also needs six instructions (or two with a MVM) to transfer to the discrete outputs.

OP does not have shift instruction, so they will have to multiply by 2 and carry pseudo-Y2 to pseudo-Y0 manually.

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[parky]

Ah... That's where the Mitsi is clever, the bit shift has a parameter that determines how many places to shift it so if set to 3 then it only shifts Y0 to 2.
TBH, it probably won't save any scan time as their function probably does the indirect transfer to the bits using a pointer so the real code behind it takes as many instructions to process.