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S772 Digital Servo Amplifier Setup

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I am way behind the curve on this. I have an S772 drive controller that I am trying to set up. We have had this drive sitting on a shelf for a long time. I have a laptop set up with Windows 7, an RS232 cable, but no serial port on the computer. I bought a serial port to USB converter cable and opened the USB in the manager to be used as a COM port (for use with serial cable). But when I connect the computer and the drive units together, I get a faulty parameter error message which essentially means the drive and the computer are not communicating properly. I have confirmed the wiring on the RS232 cable with page 98 in the manual (see attachments), but cannot resolve this issue. Any advice on how to get the 2 machines communicating so we can set up the drive would be greatly appreciated.

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Per the S748-S772 Installation Manual, drives that have been stored more than 1 year require the capacitors to be reformed prior to use otherwise the drive may fail.

See manual for details ( Storage page 17 ),.



As you mentioned the RS232 serial connection is shown in the manual ( page 103 ). Are you using a shield?



A couple of thoughts on issues connecting using the Drive GUI software.

I’m using the latest from our website:


I like to check in Device Manager what virtual COM port number is assigned to the USB to Serial Converter.


In my case the COM port is COM4.



Go to the Communications pull-down menu->Device Parameters.




Select the COM number for the USB to Serial Converter assigned and verified in Device Manager.




Click OK to accept the Serial Port setting.





From Communication pull-down menu-Connect.





There were no communication errors and from the bottom status bar in the DriveGUI software it reads Ready and Online indicator lamp is GREEN.





Unfortunately we do not publish a list of tested USB to Serial Converters and sometimes it requires your experimentation with several brands.


Link to USB to the RS232 converter used by our group.


If you have a PC with a true serial port that can also be an option to take out the potential of converter issues.


We can also offer assistance via a web based meeting such as Teams, Team Viewer, etc.


It would be beneficial to take a photograph of each drive’s nameplate sticker on the side of the drive to note and record model numbers, hardware , and firmware revisions.


Thank you Todd! When our ETs come back in tomorrow, I will go through this with them. Firstly we will take care of reforming the capacitors.

With regards to the COM ports, I did select the port on the computer, but I did not reflect that selection in the GUI set up app. I will do that today.

I have bought a couple different serial to USB converters. How to identify what is different within each, I have no idea. But we will continue trying until we get that green light showing online connection.

Thank you very much for your input. We greatly appreciate you taking the time to consider our dilemma and providing us with some options.

All the best~


Pacific Subsea ... - Thu, 08/13/2020 - 16:38

Ok, we've made some progress. I have confirmed both sides of the COM port (laptop and drive). The 2 machines are now communicating. Now we are seeing a spinning cursor situation that doesn't stop spinning. That is one of our next hurdles. The other hurdle is the fact that we are using this drive to replace the out dated BDS4 drive unit. And our techs are now confused about how to connect the button trigger (operation) for this drive. One momentary button for direction motion (up). And another momentary button for direction motion (down). The contacts and locations are very different between the 2 drives. They are digging through the manual, and not coming up with much in the way of answers or solutions. I will get some pics to sort out what the 2 drives are we are looking at.

Pacific Subsea ... - Fri, 08/14/2020 - 23:47
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