Siemens Step 7 PLC Programming

I am currently working on a project with a Siemens S7-313 Cpu. I was wondering if it is possible to control a time value of a timer using a 10K Potentiometer connected to an Analog Input??

Alan

Sorry, but I am going to answer you with a question

Why would you want to do this, what is wrong with using a BCD thumb wheel input?

Paul

The timer preset is a number. An analog input is a number. There is no reason why the analog input value can't be used as a timer preset.

You only need to do the arithmetic to scale the analog data value to the range of timer presets you're looking for.

Re : PLucas

Alan

Sorry, but I am going to answer you with a question

Why would you want to do this, what is wrong with using a BCD thumb wheel input?

Paul


I am trying to keep new control system as before and timer value was originally set by a pot.

Alan

Alan

Thanks for your reply, I now understand why you would want to use a pot, instead of a digital input.

As Steve Bailey stated in his reply, there is no reason why you can't, you just have to get your scaling right.

Good luck with the project.

Paul

Hello !
I ones made a projects where one could change the timer time in the program. Ok it was S5 I used a ineteger value kf eg. 5 and added
a timer value eg. kt 0.2, then the value would be kt 5.2 wich should be 5 seconds. (it's been a little bit of time since that project or S5in general so It can be that I remember the KT and KF in the wrong way)

In general:
read the analog analog value scale it -> transform to integer ? and try to add it to the S5T# 0sek...? -> move the value to the timer.
I don't know how the timer will react if you change the value while the timer is running or do you need to add eg. a button wich will trigger the move command to the timer.

If you would use eg. a OP-oanel everything would be much more easier....

BR.
Nicke
zzzzz

Because the S5 Time format is used for the preset time, it is difficult to move the signal from the analog input to the timer. I have created a project, with a timer block, that will allow the analog signal to be the value X100ms and have attached it for you.


Thanks Phil, for making the file attachment large enough for this file.

Hi Alan, I was wondering if you had your problem sorted out yet?
I have used something very similar to what you want to do for controling the speed of an inverter through a plc using a Pot for an analog value scaled through the PLC.

If you need any help just shout.

Barry