S7 300 Basics and stuck

[geniusintraining]

OK I am not very good with the 300, as a mater of fact I suck... but that said I still can not figure out why my outputs are working

      A     I      0.1
      AN    I      0.2
      L     MB     0
      T     QB     0
      L     MB     1
      L     1
      +I    
      T     MB     1
      T     QB     1

Simple little project, I have a 313 CPU and SM374 combination I/O (making a cheap S7 300 trainer) the I/O card has the dip switches to simulate inputs and the LEDs are my outputs

Top 8 on the card are outputs and the bottom 8 are inputs

I am just wanting the lights (LEDs) to flash and to test the I/Os... with the above OB1 I get the LEDs to flash but would of thought that they would stop once input 1 is off or input 2 is on

When I click on the monitor icon I see the inputs turning on and off (going true) but the outputs never stop flashing

Thanks for your help

 

[PLCKeef]

Load and Transfer will be executed ragardless of the RLO , so maybe try something like this ?

A I 0.1
AN I 0.2
A(
L MB 0
T QB 0
L MB 1
L 1
+I
T MB 1
T QB 1
)

 

[geniusintraining]

Thank you, I will try it tomorrow

 

[ivo.maenen]

The MOVE-instruction can be made conditional.

 

[KalleOlsen]

Hi git!

I would use a jump here:
A..
AN..
JCN L001
:
:
L001: NOP 0

But, in general if in doubt: Write the code in LAD and let S7 translate it to STL.

Kalle

 

[Jeebs]

Load, transfers, math and quite a few other instructions are done without regards to the RLO.

This is a simple rule with few exceptions:

If you don't want to execute the logic and it isn't bit-logic, use one of the various jumps.


The sooner you learn it, the less grey hair you'll get. (from working with siemens )

 

[JesperMP]

I say, program in LAD, and stay in LAD.
It is easier and less error prone.
Noone will give you a medal for programming in STL.

 

[geniusintraining]

...so maybe try something like this ?

Thank you for the suggestion but it did not work

I would use a jump here:

Hi Kalle, worked great, thank you!

the less grey hair you'll get.

I pulled that out a long time ago

Noone will give you a medal for programming in STL.

Hmmmm then how do you explain this

 

[KalleOlsen]

Hi git!

I think it's wise to learn about STL - it is very powerful, and doesn't need to be messy. Best suited for calculations and data moving.

More S7-stuff here, might be worth a closer look:http://www.automation.siemens.com/M...DOWNLOAD_TRAINING_MATERIAL/Pages/Default.aspx

Kalle

 

[JesperMP]

Hmmmm then how do you explain this

I think they are fake.

Seriously, the kind of code you listed in the 1st post would fit LAD perfectly.
To my opinion, STL should be relegated to being the last resort.

 

[TurpoUrpo]

I would not level it to last resort. But for jobs it suits well. Most can be done more effectively with SCL tough.

But, learning it is easiest by first learning trough lad->stl conversion and then continuing with that.