Taidacent RS485 Serial Port Digital LED Panel Meter TTL Display Module PLC communication MODBUS 3 4 5 6 Digit 7 Segment Display (6 Digit, RS485)

Bought one of the displays, and had no luck getting any of the 'ascii' commands to display anything. I was able to get a few of the modbus examples to work, but most of them didn't do anything either. Requested help from the vendor, and they verified that "the 6 digit meter does not support ASC form". They included the "full" datasheet for the unit, which show no support for changing the color or the brightness via modbus. There is also something wrong with their implementation of the modbus command for 'displaying floating point numbers". The last digit is always one less than it ought to be. So if you tell it to display 1.2345, it displays 1.2344. Decimal location doesn't matter; 123.45 shows as 123.44 So, you're not getting the simple ascii protocol at all, the modbus protocol does not support all the commands they claim, and at least one of the commands the support is buggy.