TPU2000/2000R Modbus/Modbus Plus Automation Guide
81
Within this Automation Technical Guide several designations are given for the source data type. Each value
reported within a 4X Register has a separate designation. Example data type designations available for scaling
and re-mapping are as follows:
Unsigned Long Register 40385 Restraint Current A Winding 1
32 Bit Register Unsigned
Unsigned Short Register 40260 Restraint Current A
16 Bit Register Signed
Unsigned Long Registers 40513 Voltage Phase A
32 Bit Double Register Unsigned
Signed Long Registers 40528
40528 kWatts Phase A
32 Bit Double Register Signed
The query field may contain any of the above four register types for data transfer.
Source Scale Range and Source Scale Type Selections Explained
Scaling is determined by a simple formula depending upon the SCALE TYPE, FULL SCALE/SCALE FACTOR,
SCALING OPTION, and DESTINATION LENGTH, values
.
Each of the 4X registers defined within the Modbus Protocol Document are classified by being a Current Value,
Voltage Value, or Power Value. If one of these aforementioned scale types are selected, the value in the FULL
SCALE/SCALE FACTOR field is designated as the maximum value of the unscaled source value. If the source
value is above the configured FULL SCALE/SCALE FACTOR field value, the maximum value (as shown in Table
X) will be reported as the destination register scaled value.
The values within the relay may be scaled by an integer factor if a normal or remainder scaling type is selected. If
one of aforementioned selections are within the FULL SCALE/SCALE FACTOR selection field then the selection
is automatically the scale factor.
The allowable values for the FULL SCALE/SCALE FACTOR field are from 1 to 65535. This is equivalent to the
secondary quantities and the relationship to the primary quantities being scaled as per said formulas below.
(which should be familiar to those of you who are “old” transducer engineers.)
If one of the voltage, current, or power SCALE TYPES are selected, then one or more of the following CT /PT
ratio values must be known to compute the destination scaled value. The quantities which must be known to
compute the equations for scaling are:
40158:
Unsigned Short
Phase CT (CT)
40159:
Unsigned
Short
Neutral
CT
Ratio
(CT)
40160:
Unsigned
Short
PT
Ratio
(PT)
NOTE: If the quantity being scaled is a Phase Current then the Phase A CT value entered in WIN ECP is used in
the following equations. If the quantity being scaled is a Neutral Current value, then the Neutral Current CT is
used in the following scaling equations. The values may be viewed from the ECP/WinECP program as illustrated
in Figure 5-16.
IF OFFSET BIPOLAR CURRENT IS SELECTED
EQUATION 5:
Register Value = (2
N-1
*
Source Value / [FS
*
CT Ratio])+2
N-1
-1
IF OFFSET BIPOLAR VOLTAGE IS SELECTED
EQUATION 6:
Register Value = (2
N-1
*
Source Value / [FS
*
PT Ratio])+2
N-1
-1
IF OFFSET BIPOLAR POWER IS SELECTED
EQUATION 7:
Register Value = (2
N-1
*
Source Value / [FS
*
CT Ratio
*
PT Ratio])+2
N-1
-1