ABB TPU2000, Technical Manual, Page: 94 / 374

TPU2000/2000R Modbus/Modbus Plus/ Modbus TCP/IP Automation Guide
84
Full Scale =
10 MAX VALUE ALLOWABLE ON FPI = 10 * CT ratio.
CT Ratio (Current Calculation) = 100:1 (as per the default screen shown in Figure 8-2)
Source Value Location = 385 [ 16 Bit Value Signed
Calculate the 12 bit scaled reading when the TPU2000R indicates 5A for Ia.
(12 bits -1)
(12 bits -1)
(( 2 * 5A)/(10 * 100)) +(2 - 1) = 3071 counts.
Thus Equation 7 illustrates that a current of 5A displayed on the MMI shall indicate a count of 3071 reported to the
SCADA Host when register 40002 is read. The SCADA host shall then interpret it and display it on its host screen
as 5 A.
Perhaps another example shall suffice. The TPU2000/2000R also meters voltages. The next example illustrates
the scaling which occurs for the default registers, 40006, and 40007. Figure 8-8 shows the scale algorithm
application for scaling to an Offset Bipolar 12 bit number.
Change Register Configuration
E
C
NORMAL
FAIL
PICKUP
RECLOSER OUT
SYSTEM RESET
TIME
INSTANTANEOUS
FREQUENCY
NEGATIVE SEQUENCE
TARGET RESET
STATUS TARGETS
A
B
C
N
DPU
2000R
Network
Partner
V1.0
TPU2000R
32
Mappable
Registers
400001
.
.
.
400005
400006
400007
400032
Va Voltage Mag. Hi
VbVoltage Mag. Hi
40265
40266
40268
40269
40271
40272
Vc Voltage Mag. Hi
Va Voltage Mag. Lo
VbVoltage Mag. Lo
Vc Voltage Mag. Lo
OFFSET BIPOLAR
12 bit resolution
0 = (-) Full Scale
(12 bits -1)
2 - 1 = 2047 = 0
(12 bits)
2 - 1 = 4095 = (+) Full Scale
(+) Full Scale = 50000 V = FS * PT
(-) Full Scale = - 50000 V = FS * PT
0 Amperes
RTU or Host Reads 0
RTU or Host Reads 2047
RTU or Host Reads 4095
TPU 2000/2000R Metered Value reported
to the MMI SCREEN
Value stored in Registers
40005, 40006,and 40007 read by
the SCADA Host.
Figure 5-32. Scaling Example for Voltage Mapped Registers
The values used for this example are:
Full Scale =
500
PT Ratio (Current Calculation) = 100:1
Source Value Location = 513 [neglect the leading 4] 32 Bit Value Unsigned
Using Equation 6 the following results when calculating the numeric value reported to the SCADA host when
register 40005, 40006 or 40007 is accessed.
(12 bits -1) (12 bits -1)
(( 2 * 11884)/(500 * 100)) + (2 - 1) = 3699.562 counts
1622.562 + 2047 = 3699
When the front panel MMI reads 11884 V, a value of 3699 is reported to the SCADA host.
One final example is illustrated for transferring values from different areas in the protective relay to the default
table. Such values as Relay status (located in register 40129 and transferred to 40001), Phase CT ratio (used by
the SCADA host to provide for scale conversion located in Register 40158 and transferred to 40016), PT ratio
(used by the SCADA host to provide for scale conversion in Register 40160 and transferred to 40017), and
system frequency (located in Register 40027).