Modbus Protocol for ION 7500, ION 7600 and ION 8000 series

Modbus Register MapModbus Register Configuration (Modbus Slave Module)ScalingThe Modbus Slave Module can scale and offset input values to fit within the outputrange for the selected format. The Scaling setup register selects if scaling (asdefined by InZero, InFull, OutZero, and OutFull) is applied to the inputs. Thefollowing values are valid for the Scaling setup register:0 = No1 = YesInZero, InFullIf Scaling is set to YES for a Modbus Slave Module, the input values are scaledaccording to a formula derived partly from the InZero, InFull setup registers. Inputvalues falling at or below InZero are represented as OutZero. Input values fallingat or above InFull are represented as OutFull. Input values between InZero andInFull are represented as a proportionate value between OutZero and OutFull.InZero and InFull are defined to range from -1x10 38 to +1x10 38 , but via Modbus,these registers are represented in Signed 32-bit Integer format, so the integerbounds of -2,147,483,648 to +2,147,483,647 are imposed upon these registers.OutZero, OutFullIf Scaling is set to YES, the input values to the Modbus Slave Module are scaled bya formula derived partly from OutZero, OutFull. The absolute range of theseregisters is -2, 147, 483, 647 to +2, 147, 483, 647, but the valid range variesdepending on the selected Format for the Modbus Slave Module. The followingchart shows the OutZero, OutFull ranges for the various Formats:Table 6: Out Zero and Out Full ranges for Modbus formatsFormat Low Bound High BoundUnsigned 16B 0 +65535Signed 16B -32767 +32767Unsigned 32B 0 +2,147,478,647Signed 32B -2,147,478,647 +2,147,478,647Unsigned 32B-M10K 0 +65,535,999Signed 32B-M10K -32,767,999 +32,767,999Packed Boolean N/A N/APage 23