The Craftmans Shop > New from Old
The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
awemawson:
Thanks Pekka, not come across FUB but I do know LOTS about FUD or Fear Uncertainty and Doubt :clap:
I can display the PLC program as CSF, LAD or STL
CSF - Control System Flowchart
LAD - Ladder
STL - Statement List
But I suppose not all constructions are possible to display in some formats hence interspersed statement lists. Here is an example of SEG-2 in all three formats
Incidentally that I4.4 is eSTOP, I7.7 is 24 volts OK, Q 7.0 is a spare output, but I have as yet no idea what F 24.3 is except that it's an internal flag bit, or what Q78.1 is, again it's an internally used output from the range it sits in.
Perhaps I should explain I's are inputs F's are flags (temporary one bit memory) and Q's are outputs. So Q 1.2 is output word 1 bit 2 for instance which would be 'select low gear on this lathe.
( all this is me trying to familiarise myself with what I'm working with - sorry if I'm boring you all :scratch: )
awemawson:
So continuing on the theme of self education, and boring the pants off you, segment 1 translates as follows:
Segment 1
:STL
:L KH 0202 Load Hexadecimal 0202 into Accumulator 1-L
:T FW 121 Transfer contents of Accumulator 1-L into Flag Word 121 bits 8-15 to byte n, bits 0-7 to byte n+1
:L KH 0020 Load Hexadecimal 0020 into Accumulator 1-L
:T FW 119 Transfer contents of Accumulator 1-L into Flag Word 119 bits 8-15 to byte n, bits 0-7 to byte n+1
:***
Which can only be represented as a statement list, as flowchart or ladder are not appropriate
tom osselton:
Not that boring but does make one scratch their head!
I’m waiting for the lightbulbs to turn on!
awemawson:
You and me both Tom :thumbup:
I've just spent the evening gleaning all the 'I bits' (ie inputs) from the circuit diagrams that I have and typing them into a cross reference file that STEP5 uses to translate absolute labels (such as I 8.1) into symbols.
Next task is to do the same for all the outputs (Q bits) from the circuit diagrams, then try and pick up the internal 'standard' flag words from the 'Guide to writing PLC programs from Siemens.
Hopefully when those tasks are completed the 33 pages of program will be more user friendly bed time reading :lol:
. . . of course all this effort is no guarantee that the 'M20' issue that I'm seeking will be revealed, or indeed that the issue is even IN the PLC :bugeye:
AdeV:
--- Quote from: awemawson on October 22, 2018, 09:54:13 AM ---
bits 8-15 to byte n, bits 0-7 to byte n+1
--- End quote ---
Ugh, I hate little-endian systems with a passion, they just don't feel right.
BTW, you might already have this manual, I can't remember off-hand, but in case it's useful, it appears to contain a Step5 programming manual: https://cache.industry.siemens.com/dl/files/940/1085940/att_1156/v1/pa928ben.pdf
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