Best practice for programming a sequence with variations

AutoGen_6815244

Just let the condition for the next step be true when there is a product that doesn´t need that step.

I cannot do that. If I don't require Step3 I cannot set it to true.
If some product requires S1 > S4 > S5 I cannot make S4 go true just becase S1 was completed...

Later some other product requires S1 > S2 > S3 > S4 > S5 and in that case this one would also skip straight from S1 to S4.

 I don´t understand why.

Have a look:

A step need a transition or the information that it isn´t needed to set the next step and resets itself.

When a step isn´t needed it will be set but reset in the next network. This all happens in one cycle.

regards,

I feel horrible that I have given you a somewhat standardized approach (based on seeing it done by multiple vendors and plc programmers) for handling operational sequences without a full state machine approach.

What you want is a finite state machine (search online if you do not know what it is.. everyone has to look it up once).

If you feel comfortable searching for a finding a FSM library and then using it, by all means, do that.  It is much safer than trying to develop your own from scratch.

It is a moderately advanced "computer science" approach, but is a perfect fit for your made up example project.

AutoGen_6815244

Its not that funny and I think I have a so called algorithm in mind.

Every step has a "calculating" function in front of it that looks at the current product parameters - the required sequence, and decides if this step was required or not.

I have not found a way to search for the last TRUE array member, starting from a specific array member.
As in looking backwards from STEP[4] .... to see if STEP[3] was TRUE or STEP[2] was TRUE or STEP[1] was TRUE.

IF STEP[2] was TRUE ... use the "Processing_DONE" bit from STEP[2] as the starting criteria for STEP[4]

Do you guys follow?