Hello kamyar;

What serial port do you mean? You can use the USS protocol to control a Siemens drive over RS-485 (you can also use Profibus-DP, which uses RS-485 also, but then you need a processor for your MM4 drive).

Here are the specifictions of the USS protocol:

Specification: Universal Serial Interface Protocol USS Protocol

Do you plan on controlling the drive froma PC, a PLC?

The only implementation of the USS protocol on a PCthat I know of is part of the SimaticDrive ES package:

https://w3.usa.siemens.com/us/SiteCollectionDocuments/WSSResources/Internet/Products/11_20/13/DriveESShortStart-upInstructions.pdf?HTTPS=REDIR

S7-200 PLCs can add a USS protocolMicrowin library (to be purchased) to control drives:

Where in STEP 7 Micro/WIN can I find the operations libraries for the Modbus RTU protocol and USS protocol?

The protocol functions are described here: S7-200 System Manual

S7-1200 PLCs have an included USS library in Step 7 Basic, V. 11 and V. 12. For example, look in the following manual:

STEP 7 Basic V11.0 SP2

On the S7-300 distributed IO (ET 200S) you can use a 1SI serial CP to use the USS protocol; you can dowload the library from the link in this FAQ:

What changes do you have to make in the sample program "USS Protocol" in order to operate multiple slaves on the ET 200S 1SI module?

Hope this helps,

Daniel Chartier