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Limitorque Master Station III FCD LMENIM5001-02 – 12/13
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8.2.5.3.1 Modbus FC 02 Read Input Status
Touching the “Modbus FC 02 Read Input Status” button will take the user to the FC 02 Read Input
Status Screen (Figure 8.23) for selection of desired input status bits from field unit holding registers
9-13. There are two ways of doing this: Standard and A/B Style. Standard style is a static mapping
of register status bits as seen in Table 8.1. A/B Style is a dynamic mapping of register status bits as
selected using the register tables based on Table 8.1. Choose the mapping style according to the
expatiation in Section 8.2.5 DCS Configuration.
Figure 8.23 - FC-02 Read Input Status
Selecting the “Next” button will advance the screen from registers 9 through 13.
In standard mapping mode the Function Code -02 mapping is a static mapping of the total input
table as shown in Table 8.1 per MOV. A total of 80 bits represent an individual MOV. The use of this
function code will provide the user with the input status bits that are used to develop holding registers
9 through 13. Only the enabled bits will be returned as valid data (otherwise, zeros). Address affect
is accounted for in MS III decoding process (i.e., 10,000). The A/B mapping style operates similarly
but with the exception that only enabled bits return data. So where the Standard Style returns all bits,
valid or not, A/B Style returns only the bits that are selected.
Table 8.1 - Status Bit Definitions
Bit Number
Modbus
Bit
Address
MX/DDC
129
128
Opened
130
129
Closed
131
130
Stopped in mid-travel
132
131
Opening
133
132
Closing
134
133
Valve jammed
135
134
Not in remote
136
135
Combined fault
137
136
Over-temperature fault
138
137
Actuator in Stop Mode
139
138
Channel A fault
140
139
Channel B fault
141
140
Open torque switch fault
142
141
Close torque switch fault
143
142
Valve operated manually fault
144
143
Phase error
