sinamics v90 control speed and reading ampere

hi

i'm using plc s71500 with sinamics v90 pn i manage to control the servo using sina_speed FB but when i change the telegram from 1 to 3 to read the current and alarms the SINA_speed FB stop working then i tried to use SINA_para alone it works and i suceeded to read current but when i tried to run motor (using access input output address) the motor run and SINA_para stop

the question is can i run the motor using Sina_speed and read the parameter using sina_para at the same time

Hi, 

in general it does not really make sense in my opinion to read the actual current with acylic commands because that is just too slow to really see what is going on during acceleration / deceleeation phases. 

It makes more sense to put the current into the cyclic telegram and extend it by the current actual value or to use e.g. telegram 352 (contains the current) with the according SINA_SPEED_TEL352 FB

--> but now the bad news: this is not available for SINAMICS V90. I cannot see any telegram that V90 supports that includes the current value. And I think there is no option to create your own telegram with free BiCo. 

So if I am not wrong there is simply not really a good solution for you to transfer the actual current to the PLC with your drive. Only way is acyclic with SINA_PARA. And yes it is of course possible to have the SINA_SPEED (for cyclic communication with telegram 1) and the SINA_PARA (for acyclic reading) in parallel working. With SINA_PARA you just need to know that you request a value and you will get just one single value from your request. After you read one value you have to request the next value and so on. So this is why I say acyclic communication does not really make sense to read actual values from the drive. 

What I am always asking myself: What is the reason to read out the actual current in the PLC? What would you do with that information. In fact the communication cycle is anyways slower than the current controller in the drive - so you won't really see every short peaks in the current.

first thank you alot to answer me

i need to read the actual current for the motor because in my project its related to the pressure of rubber roller on the drum which run with the motor so if this rubber happen to has any problem it will reduce the current so i can alarm the operator to change it

here i used sina_speed with telegram 1 and it work but for sinamics v90 to read the parameter i need to use telegram 3 and i can't use more than one telegram with sinamics v90

i really mangage to read the motor temperature and current but i cant run the motor

Ok I see, so instead of the current I think also the torque information would help you, right?

I mean torque and current are in proportional relation.

To read the actual torque you can add supplementary telegram 750 to the V90.

Then you have 2 telegram slots -> telegram 1 to run SINA_SPEED and a separate slot for telegram 750 which you could handle in your PLC program for example by using the "GETIO" function - the needed HW ID is the one from the telegram 750.

I just tried it out myself.

In TIA there are 2 options how to integrate the V90PN:

1. via GSD file

2. via Hardware Support Package (HSP)

No matter which way you choose - for both it is possible to add telegram 750. Please see my attached screenshots. I also made one of a simple PLC program to read out the telegram data.