Hi everyone,

I'm new to the Siemens world and am working on a project with the SINAMICS V20 and a LOGO! PLC. I’d appreciate some guidance on my configuration to see if I'm on the right track.

My goal is to achieve a multispeed control setup with 8 speeds. I'm using three relays connected to DI2, DI3, and DI4 for speed selection, and I plan to use another digital input for run/stop control.

I decided to go with digital control rather than adding an analog expansion module to the LOGO!, as it seemed more straightforward. Additionally, I'm considering adding a potentiometer to AI1 as a backup, in case the LOGO! encounters any issues.

One question I have is regarding the analog output AO1. I know it outputs 0..25 mA, but I’m curious—can it also be configured to output 0-10V?

Thanks in advance for any advice or insights!

Hello PaulFaud,

You've landed in the wrong section with your questions about the converter .

As I understand from your text, you want to use the connection macro Cn003. But the analog input is not available to you. If the Logo fails, you would have to intervene in the parameters every time. A switch solution parallel to the digital inputs would be better.

And why the resistor R2? You can set that with the minimum speed in the parameter settings .

But what puts you off the analog coupling between the converter and the Logo? You have many more options when it comes to the number of fixed speeds. And if you change the values, you don't have to go into the converter's parameters.

As far as the analog output AO1 is concerned, a short answer: No.

Regards Ella_68

(translated by google)

The problem, as I have read, is that Cn004 does not query the analog input AI1 and AI2 at all .

For what you have in mind, I would rather choose the Cn002 or Cn005 mode and use the Logo to determine the speed.

You only need a few muxers in the program for this (see "Speed 1-8").

For emergency operation, you can use a 2-pole changeover switch that switches between the analog output module and the potentiometer. This can be implemented as a key switch.

I would never give an operator access to the parameterization level of a converter. The risk is simply too great that they will change other things and damage the converter or the system.

Regards Ella_68

Many thanks,

The issue is that I want to use a multispeed option to create a more cost-effective prototype without an analog extension, as I don’t require precise speed regulation during operation.

I may need to purchase a V20 and experiment with various parameters rather than using some macro. Perhaps supervising the output of the V20 could also be helpful.