Table 5-44. State Truth Chart For Physical Input Forcing Function - ABB TPU2000 Technical Manual

Bit 8 Input 9 (Terminal 12)
Bit 9 Reserved
Bit 10 Reserved
Bit 11 Reserved
Bit 12 Reserved
Bit 13 Reserved
Bit 14 Reserved
Bit 15 Reserved (msb)
Group II functions operate as follows:
Register 41420 = Force Physical Input Change Mask - Selects Control for the Function Specified.
Register 41421 = Force Physical Input Normal State Mask - Places Bit in Normal or Force Mode.
Register 41422 = Physical Input Forcing State Mask - If Bit is in Force Mode, Determines Force State.
A Truth Table for the aforementioned bits follows as illustrated in Table 5-44:

Table 5-44. State Truth Chart for Physical Input Forcing Function

Bit Value
Change Mask Normal/Forced Mask
Register 41420
0
1
1
1
Note: X = Don't Care State
Once an input is forced on or off, it must be "unforced" or returned to normal state for the point to resume normal
operation and reflect the state present at the physical input terminals present at the rear of the relay. It is
important to emphasize that the forced states are stored in the TPU2000R's non-volatile RAM and will
remain forced until unforced by the operator. A point may be "unforced" via the front panel MMI, DOS
ECP, WinECP, or through the Modbus commands covered within this section.
A simple example illustrates the Force/Normal control sequence via the Modbus command operations. Figures 5-
48, 5-49, and 5-50 illustrate the word patterns which must be transmitted to the TPU2000R to complete a Force
ON, Force Off and Return to Normal State Operation within the TPU2000R. As with the other control functions,
the registers may be sent down individually, in blocks of data transferred, or as one block of data followed by an
execute command as illustrated in Figures 5-48, 5-49, and 5-50.
TPU2000/2000R Modbus/Modbus Plus Automation Guide
Bit Value
Register 41421 Register 41422
X
0
1
1
1 = Force Set State 0 = Force Reset State
1 = Force Set State 0 = Force Reset State
1 = Force Set State 0 = Force Reset State
Bit Value
Forced State
X Normal - State follows Voltage at Term.
X Normal - State follows Voltage at Term.
0 Input Forced – State = OFF
1 Input Forced – State = ON
Description
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