The OPC server is connected to a temperature-control instrument. The instrument's display reads negative, but the number in the OPC Quick Client reads backwards from 65535. For example, -2 reads as 65534.
Change the tag from an unsigned integer (such as Byte, Word, or DWord) to a signed integer of the same size (such as Char, Short, or Long). If using a Dynamic Tag in the client application, specify a data type that is different from the driver's default setting for that memory type. To do so, append an @ sign and the server's name for the data type to the client's Item ID. For example, a standard Modbus device in the Modbus Driver would be "Channel1.Device1.400001@Short".
Note: For more information on Dynamic Tags, refer to "Dynamic Tags" in the server help file.