Siemens Statement Logic

ControlsDude17 · Oct 18, 2021

Hello Everyone,

I am not proficient with STL so I wanted to get another opinion on this big of logic.

A(
L #MaxPos //maximum position [mm] greater than...
L DBD [AR1,P#2.0] //...absolute pane position [mm]...
>=D
)
A(
L DBD [AR1,P#2.0] //...absolute pane position [mm]...
L #MinPos //...and minimal position [mm]...
>=D //...less than absolute pane position [mm]...
)
JCN N1Lo

I read this as my DBD[AR1,P#2.0] both has to be Larger or equal to #MaxPos and Less than or equal to #MinPos in order to execute JCN N1Lo.

Is this correct or am I misreading this?

drbitboy · Oct 18, 2021

https://support.industry.siemens.co...-s7-300-and-s7-400-programming?dti=0&lc=en-WW

I think OP's interpretation might be backwards; I think it is evaluating

#MaxPos >= DBD [AR1,P#2.0]

AND

DBD [AR1,P#2.0] >= #MaxPos

>=D is (ACCU 2 >= ACCU 1) where ACCU 2 and ACCU1 are both double integers. ACCU 1 is the most recent L argument; ACCU 2 is the next most recent L argument, so in the first [AND with Nesting Open] A( ... ), when the close paren is reached, #MaxPos is in ACCU 2 and DBD [AR1,P#2.0] is in ACCU 1.

The L (Load) shifts the accumulator stack up and "pushes" it argument onto the at ACCU 1.

========================================================================

4.3 L Load Current Counter Value into ACCU 1
Format

L <counter>

[...]
Description

L <counter> loads the current count of the addressed counter as an integer into ACCU 1-L after the contents of ACCU 1 have been saved into ACCU 2.

========================================================================

2.3 ? D Compare Double Integer (32-Bit)

Format

==D, <>D, >D, <D, >=D, <=D

Description of instruction

The Compare Double Integer (32-bit) instructions compare the contents of ACCU 2 with the contents of ACCU 1 .The contents of ACCU 2 and ACCU 1 are interpreted as 32-bit integer numbers. The result of the comparison is indicated by the RLO and the setting of the relevant status word bits. RLO = 1 indicates that the result of the comparison is true; RLO = 0 indicates that the result of the comparison is false. The status word bits CC 1 and CC 0 indicate the relations ‘’less,’’ ‘’equal,’’ or ‘’greater.”

Ken Moore · Oct 18, 2021

It is a limit test, must be <=MaxPos and >=MinPos.

#MaxPos >= DBD [AR1,P#2.0]
AND
DBD [AR1,P#2.0] >= #MinPos

drbitboy · Oct 18, 2021

Also note that, if OP's original interpretaion was correct, and if #MaxPos is less than #MinPos, then routine [N1Lo] can never be executed.

ControlsDude17 · Oct 18, 2021

STL Logic

Ken Moore said:
It is a limit test, must be <=MaxPos and >=MinPos.

#MaxPos >= DBD [AR1,P#2.0]
AND
DBD [AR1,P#2.0] >= #MinPos

This makes more sense to me, it was just that in trying to interpret the STL logic, I had twisted it around. Basically, it states that if DBD [AR1,P#2.0] is between #MaxPos and #MinPos, then RLO = 1?

Ken Moore · Oct 18, 2021

Yes, if the value is within limits, RLO would = 1, and the JUMP would not occur.
Because JCN = JUMP if RLO=0.

ControlsDude17 · Oct 19, 2021

Ken Moore said:
Yes, if the value is within limits, RLO would = 1, and the JUMP would not occur.
Because JCN = JUMP if RLO=0.

So the full version of the code.

A(
L #MaxPos //maximum position [mm] greater than...
L DBD [AR1,P#2.0] //...absolute pane position [mm]...
>=D
)
A(
L DBD [AR1,P#2.0] //...absolute pane position [mm]...
L #MinPos //...and minimal position [mm]...
>=D //...less than absolute pane position [mm]...
)
JCN N1Lo
L #Count
T #TPane
N1Lo: L #Count
LOOP skn1

If I am between Max Pos and Min Pos, then RLO = 1 and I move #Count into #Tpane. If RLO = 1, jump to N1Lo?

Just want to verify because if so, this is opposite of the outcome I want and I would want to change that "JCN" to "JC".

RVaughan · Oct 19, 2021

If between MaxPos and MinPos, RLO = 1, do not jump, move #Count to #TPane, then load #Count, then loop.
If outside of MaxPos / MinPos, RLO = 0, jump (Do not move #Count to #TPane), then load #Count, then loop.

ControlsDude17 · Oct 20, 2021

Additional

Can I get some help with is part too?

Trying to isolate why we are faulting when it appears that our Value is within the limits.

L #MaxNoPane //maximum number of panes
skn1: T #Count
L 1
-I
L #S_PaneData //length of pane data array
*I
L #P_PaneData //start of pane data array
+I
SLD 3
LAR1

A(
L #MaxPos //maximum position [mm] greater than...
L DBD [AR1,P#2.0] //...absolute pane position [mm]...
>=D
)
A(
L DBD [AR1,P#2.0] //...absolute pane position [mm]...
L #MinPos //...and minimal position [mm]...
>=D //...less than absolute pane position [mm]...
)
JCN N1Lo
L #Count //... -> save pane number!
T #TPane
N1Lo: L #Count //...otherwise: check next pane!
LOOP skn1

L 0 //if no pane was found...
L #TPane //...between the parametrised position...
==I
S #DevFlt //...-> set fault
JC NotF //...-> goto: no pane found
L #TPane //...otherwise:
+ -1
L #S_PaneData //length of pane data array
*I
L #P_PaneData //start of pane data array
+I
SLD 3
LAR1

L #NewPos //get deviation
L DBD [AR1,P#2.0]
-D
T #ActDev

L #NewPos //copy the absolute plant position [mm]...
T DBD [AR1,P#2.0]

JU IniB

ControlsDude17 · Oct 20, 2021

ControlsDude17 said:
Can I get some help with is part too?

Trying to isolate why we are faulting when it appears that our Value is within the limits.

L #MaxNoPane //maximum number of panes
skn1: T #Count
L 1
-I
L #S_PaneData //length of pane data array
*I
L #P_PaneData //start of pane data array
+I
SLD 3
LAR1

A(
L #MaxPos //maximum position [mm] greater than...
L DBD [AR1,P#2.0] //...absolute pane position [mm]...
>=D
)
A(
L DBD [AR1,P#2.0] //...absolute pane position [mm]...
L #MinPos //...and minimal position [mm]...
>=D //...less than absolute pane position [mm]...
)
JCN N1Lo
L #Count //... -> save pane number!
T #TPane
N1Lo: L #Count //...otherwise: check next pane!
LOOP skn1

L 0 //if no pane was found...
L #TPane //...between the parametrised position...
==I
S #DevFlt //...-> set fault
JC NotF //...-> goto: no pane found
L #TPane //...otherwise:
+ -1
L #S_PaneData //length of pane data array
*I
L #P_PaneData //start of pane data array
+I
SLD 3
LAR1

L #NewPos //get deviation
L DBD [AR1,P#2.0]
-D
T #ActDev

L #NewPos //copy the absolute plant position [mm]...
T DBD [AR1,P#2.0]

JU IniB

Essentially what is going on in these lines, How do I determine what AR1 is, etc.

drbitboy · Oct 20, 2021

ControlsDude17 said:
Essentially what is going on in these lines, How do I determine what AR1 is, etc.

<Yoda voice> Help does this:

https://cache.industry.siemens.com/dl/files/814/109751814/att_933093/v1/STEP_7_-_Statement_List_for_S7-300_and_S7-400.pdf

?

L D[AR2P#0.0] · Oct 21, 2021

AR1 is an address register and can be used to access data down to the bit level. When accessing data at the byte level you have to multiply the byte number by 8, hence the SLD 3 instructions.
Your code is looping through an array where the start byte location of the array is specified in P_PaneData and the size of the array structure is specified in S_PaneData. The dint value for your comparison is located at byte 2 in the structure.

Siemens Statement Logic

ControlsDude17

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Ken Moore

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ControlsDude17

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L D[AR2P#0.0]

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