Hello everyone and good day!

Is it possible to alter telegram 352 to transmit back actual power instead of actual torque? Or do I need to use the free telegram to get this data back?

Additionally to this, is there an easy way to add data returned such as having power, torque, current etc? Do I need to use free telegram or can I extend 352 somehow, or is there a better way to read params from the drives?

I am new to drive and telegram control so a more detailed answer would be appreciated for my learning!

Thank you kindly in advance!

Alex

Hi,

yes you could change the torque value (r80) to the power value (r82). Therefore you need to change the telegram setting in the drive from telegram 352 to "free telegram". Then go to parameter p2051[3] - here you should see r80 is connected - just select r82 at this place. 

In your PLC program of course you need to rescale the value. Not sure if you are using the SINA_SPEED_TLG352 function block but it makes your life way easier. You can find it on SIOS as well (in the LSinaExt library): 

https://support.industry.siemens.com/cs/de/en/view/109747655

Using this block, it asks you at the input for the reference torque to be able to calculate the real value out of the normalized one which is transmitted via PROFINET. So here you simply do not enter the reference value for torque but for power (value of r2004). Then you will get the actual power instead of the actual torque at the FB's output.

In general there are some standard telegrams which have a fixed set of data which is exchanged. You can always change them to free telegram to adapt them to your needs. Also there is the possibility of telegram extension or supplementary data. 

Here is the behavior of telegram extension: You still have the data from the standard telegram and then extend by several words and connect the parameters that you want to transmit to the free words. The problem in my opinion is that you need to read this data in the PLC program using the same Hardware ID as it is still just one telegram. And if you use a standard FB such as SINA_SPEED for example then you need to adapt also this FB as it is intended to read exactly the amount of words of the corresponding telegram. For example telegram 1 has 2 words in send and receive direction - if you do a telegram extension then you need to also adapt the FB so that it can read more than the 2 words.

The other option is the supplementary data: I prefer this option to be honest. It means that you will have two separate telegram slots with an own Hardware ID for each. So you can still use your SINA_SPEED FB in the PLC without changing it. And additionally you create a DB in your PLC with the exact same amount of words that you use for your supplementary telegram. Then you use the function "GETIO" in your cyclic PLC program to read out the data from the supplementary telegram. 

Another way of communication between PLC and drive is the so called acyclic communication. You can read and write data acyclically. But as the name says you should not use this function to read cyclical data such as actual current, torque, power,... It should be used for all parameters that are no BiCos in the drive - so which are more setting parameters. Such as p1120 for example (changing the ramp up time). You can start acyclic commands using the SINA_PARA FB or the LAcycCom library.

Hope this summary helps you.