What is an indexer?

[IvanBratanov]

Hello! I’m in constant search for several days for something that is called indexer in the area of servo control. From this site:

https://www.valin.com/resources/articles/pulse-control-basics-for-motion-control

You can see that indexer here means a device that accepts communications commands from another device (i.g. PLC) and converts them into pulse trains to the servo driver. 
 

According to other sites however indexer is a rotating table (or something like that). Googling “servo indexer” returns that only. It has nothing to do with electronics. 
 

So what should it be? Could a positioning module, receiving commands from a PLC and converting them in pulse trains to the servo driver be regarded as indexer?

 

Thank you!

[Hati]

Indexer is a lot of thing, both what you have described are indexers. You can have fully pneumatic indexing tables or they can be motor controlled.

[kckku]

Indexers don't have to be servo controlled. It can be controlled using a VFD as well. Depends on how much you want to spend and what you need it for.

They are generally used as rotary indexers (look at Weiss) but can also be linear (Camco Precision link conveyor).

 

 

[IvanBratanov]

Thank you for the answers! I’d rather ask if a servo positioning module could be ragarded as indexer?

For example I have a Delta DVP01PU-S positioning module. It is designed to be attached to a Delta Slim series PLC and get commands by PLC’s internal communication bus. Then it converts received instructions into pulse train signals thru its outputs to the next standing servo driver.

With other words it is designed to make every Delta Slim series PLC capable of driving a single servo axis (mostly if the PLC cannot do that by its own or its output channels are insufficient). If there are few servo axes to be driven, the coresponding number of modules could be attached to the PLC.

 

So I only need to know could this module be regarded as an indexer?

[Joe E.]

I think the term "indexer" is pretty generic. I have seen some servo drives that have an indexing mode vs positioning mode. Positioning mode moves it to a particular position while indexing mode moves it a particular distance, also called an incremental move.

[IvanBratanov]

My searching gave me an answer which I posted here days ago but it never appeared. So I'm posting it again.

It seems that a positioning module could be regarded as an indexer. Here's what does this article say about that:

Its about stepper motors but it applies here as well. In my case the indexer is a type of MPU that is capable of driving a single servo axis by receiving commands from the PLC and transforming them into pulse train signals (both step and direction pulse commands).

So this explanation fits my question from the first topic  perfectly. A positioning module could be rearded as an indexer.