Siemens Logo!

[Robotstar5]

Can anyone on here write simple programs for the Logo!?, although I have done fault finding on PLC's I worked out many years ago my brain doesn't seem to be wired right to write the software odd really as I have no problems writing robot software.

 

[Sparky666]

Hey Robotstar5, may be able to help depending on what your looking to do. Have you looked at the Siemens forums As someone may have done something similar?

 

[daleyd]

I’ve not used a Logo for a while but I don’t mind having a go - i have the software on an old laptop upstairs. What is you want it to do?

 

[Robotstar5]

Hadn't thought of looking for Siemens forums, although I'd probably get flamed for asking how to do a simple traffic light program, it's probably the first practical test on the course

I have Logo!soft V8 on the PC, the comms lead and a couple of Logo's.

I did study the software and googled for examples, but they mostly seemed to be logic gate format which I struggle to understand, as I learnt PLC's in the 80's I am more comfortable with ladder logic.

I'm just trying to run a traffic light in the "man cave" so:

Red 30 secs
Red + Amber 3 secs
Green 30 secs
Amber 3 secs
Return to start

 

[Ruffian]

I know it's a cop out but cant you just do it with start delays and run times?

Start
Red on 33 seconds
Time delay 30 seconds amber on for 3 seconds
Time delay 33 seconds green 30 seconds
Time delay 63 seconds amber 3 seconds
66seconds return to start?

 

[daleyd]

A reasonably easy way (And importantly for me easy to follow!!), is something like below using on delay timers and latching relays (plus a few OR blocks)

Where each "On delay" timer is setting/resetting the next function along. Ie timer 1 runs for 30 secs (I set it for 15 secs to save time testing) and when timed out it sets the next timer and resets itself. Then timer 2 starts and after 3 secs sets the next timer and resets itself etc etc. I used some OR blocks to get red/amber on together and also as amber was used several times but you can expand this to incorporate different patterns, just create more functions as necessary

You kick it off by setting input I1 to 1 and after that it runs by itself

 

[graffian]

A reasonably easy way (And importantly for me easy to follow!!),

That looks good, nope I wasn't going to say easy.

I was given a Moeller PLC to operate my power drawbar, but it needs dos to use the softyware
and a I think Pythagoras wrote the manual.

 

[daleyd]

That looks good, nope I wasn't going to say easy.

I was given a Moeller PLC to operate my power drawbar, but it needs dos to use the softyware
and a I think Pythagoras wrote the manual.

I've never used Moeller PLC's - they are not a well known name in the PLC market despite doing some great control and switch gear.

I struggled with function block stuff - then I joined my current company and most of their products are function block based and I had to get my head around it - once you get the basic concepts it's actually very easy to visualise and I find it great for process type stuff (Analogue values, temperatures, flows etc) rather than ladder or other programming languages.

It's more difficult to *easily* do sequential type stuff (Like traffic lights!) but once you get an idea of how to do things then you can do almost anything with it.

 

[zx9]

I have over the years done lots of room and AV system control with Crestron, AMX and more recently Extron but never had the need to look at PLC control so interesting thread. Logic is still logic it is just the GUI or lack of GUI that changes.

You kick it off by setting input I1 to 1 and after that it runs by itself

Given it is a set of traffic lights I would set I1 to be high on program start or for a bit of theatre run a 1, 2, 3 light F1 style start up before switching to a UK traffic light sequence.

 

[daleyd]

Yeah there loads of different ways to start it off, I just chose the simplest one. Most plc have a set of special instructions that you use for things like this, eg a bit that’s set true for the first scan and then is set false after. I don’t know if the logo has them as it’s a relatively basic (But excellent) controller, and I’m not all that familiar with them - if not you could easily configure a self resetting pulse to do the same job.

 

[Robotstar5]

A reasonably easy way (And importantly for me easy to follow!!), is something like below using on delay timers and latching relays (plus a few OR blocks)

View attachment 236312

Where each "On delay" timer is setting/resetting the next function along. Ie timer 1 runs for 30 secs (I set it for 15 secs to save time testing) and when timed out it sets the next timer and resets itself. Then timer 2 starts and after 3 secs sets the next timer and resets itself etc etc. I used some OR blocks to get red/amber on together and also as amber was used several times but you can expand this to incorporate different patterns, just create more functions as necessary

You kick it off by setting input I1 to 1 and after that it runs by itself

Thanks for doing that

I spent ages looking at it and still non the wiser, I seem to have a mental block with FB (function block) or STL (statement list) programming

I'll have a go at copying it and if all else fails ask you to e-mail the program.

If I put input I1 as an N/C it should run at power on?

 

[daleyd]

Thanks for doing that

I spent ages looking at it and still non the wiser, I seem to have a mental block with FB (function block) or STL (statement list) programming

I'll have a go at copying it and if all else fails ask you to e-mail the program.

If I put input I1 as an N/C it should run at power on?

I’m ok with FB but I have never even attempted STL - it’s the worst programming language anyone could have ever invented! I think there’s a few different ways this could be done but I’ve used this method before and it is quite flexible in that you can add as many or few steps as you like. (Not with logo software but with a dcs software that used FB programming, but the principle is the same)

You may need to reset I1 after a short pulse - I think it may continue to set the first function so just needs a pulse (I haven’t tried leaving it on so I’m not sure - i just set it on momentarily to kick it off and it worked ok). I’ll have a look to see if there’s a function that would work today to start automatically

 

[daleyd]

Looks like M8 will do as an initialisation flag - set for true 1 scan and then resets, so you can put this in place of the I1 input and it will self start on power up

 

[daleyd]

Tried it with M8 as a start trigger - works great (I don’t have real hardware but simulation works so no reason why it shouldn’t )