Model 3095FB Multivariable Transmitter with Modbus Protocol
Modbus Protocol Guide
Page 50 of 79
8.0 Exception Handling
There are a number of exceptions that may occur. The severity of these may range from a
warning to a critical error. The LCD (if present) will display the error condition depending on
the attributes of the exception. The following tables define the criteria and list the types of
alarms and their attributes.
8.1 Diagnostic Status Bits
There are a number of diagnostic status bits that can give information about the status of the
transmitter. The user can read the status bits as discrete inputs, input registers, or as floating
point registers. This gives the user a variety of ways to get the status of the transmitter. These
registers contain the exact same information. The status registers are placed next to the Float-
ing Point PVs. In a polling environment the host should retrieve the PVs and the Status
Registers in a single query. Table 8.1, on page 50 shows the register layout of the diagnostic
status bits in each form (discrete input, input register, and floating point register). The float-
ing point status registers are in a bit mapped format.
A value of zero will indicate that the condition is FALSE (OFF), and a value of one will indi-
cate that the condition is TRUE (ON). All reserved bits will be forced to FALSE (OFF).
Meaning of Attributes:
A = Critical Alarm State (Critical Alarm status bit is set)
W = Warning State (Warning status bit is set)
D = LCD will display exception
Table 8-1 Mapping of Status Bits to Coils, Input Registers, and Floating Point Registers
Discrete
Input
Address
Input
Register
Address
Floating
Point
Register
Address
Bit
Position
Attributes
Description
0050 0119 0407 15 D Calibration Flag
0051 14 Critical Alarm: The PVs may not be valid
0052 13 Warning: The PVs are outside specification
0053 12 AD DP signal above Upper Range Limit + 10%
0054 11 W DP signal above Upper Range Limit
0055 10 DP signal above Upper Operating Limit
0056 9 DP signal below Lower Operating Limit
0057 8 W DP signal below Lower Range Limit
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