How to Read Signed Magnitude (16-bit)

The following table of values demonstrates the different expressions of 16 bit data, signed and unsigned.

The TOP Server Advanced Tag Plug-in can be used to convert an unsigned word into a signed magnitude value by using the modulo operator. 

Formula

-(({InputTag}-{InputTag}%32768))/32768)*2-1)*({InputTag}%32768)

Example

-(((TAG (Data Type Examples.16 Bit Device.K Registers.Word1)-(TAG (Data Type Examples.16 Bit Device.K Registers.Word1)%32768))/32768)*2-1)*(TAG (Data Type Examples.16 Bit Device.K Registers.Word1)%32768)

The following screenshots demonstrate the operation on the input tag 'Word1' and the output from the Derived Tag through the OPC Quick Client application.

Negative Values

Positive Values