The following issue happened during the commissioning of a 250KW project.
The system was built with 7 pieces of inverters: 6x 36KTL + 1x 33KTL-A. The inverters were connected in a daisy chain via RS485.
I started to set up the SmartLogger1000 and the assigning of the inverters. But there were no visible devices in the list. The connector was properly fixed in the SmartLogger, and the cables were properly connected in the connector.
After restarting the SmartLogger, I attempted to find the inverters two more times, but with no success. I assumed that there should be a connection issue, so asked the customer to check the connector of the first inverter in the chain, and we realized that the +/- cables in the COM port connector were switched.
After quickly fixing the cables and connected the connector to the SmartLogger, we expected the auto assign address function finding all of the inverters at last. But there should be another issue in the system, because this time only 3 devices have been found, the first 3 in the chain.
After a reset of the SmartLogger and 2 other assign attempts, we checked the Baud rate set on the inverters, but all of them were set to 9600. Since the addresses were also set to a proper domain, it should have been a hardware issue.
The customer opened inverter 3 and 4 and made sure that the cables are properly connected by +/- and IN/OUT. All the connections were done in the proper order, were fixed properly to the connector and the connector was also fixed well to the terminal, so we went to do the auto assign again… but failed again.
Checking everything from the hardware and software side, our only idea was that we have a cable break between inverter 3 and 4, but without equipment, we aborted the commissioning that day. The customer returned to the site the next day and found out with measuring, that the Ethernet cable was indeed broken between the 2 mentioned inverters, possibly because of improper installation, transportation or storage.
After this incident, the customer decided to always use PLC in his systems J
