Comparison Commands - Emerson Micro Motion 3711 Configuration And Use Manual

Function Sequence Tables
Example
Table 11-8 Logical commands
Name Description
NOT Logical NOT of SVD(in)
AND Logical AND ARG1 with SVD(in)
OR Logical OR ARG1 with SVD(in)
XOR Logical XOR ARG1 with SVD(in)
11.8.3

Comparison commands

Use comparison commands to compare values. Comparison commands conditionally compare two
values, and branch to a different sequence of commands if the comparison is determined to be true.
Otherwise, if the comparison is determined to be false, no branching occurs and the next command in
sequence is executed. Comparison commands test values for equivalence (==), non-equivalence (!=),
less than (<), less than or equal to (<=), greater than (>) , and greater than or equal to (>=).
Configuration and Use Manual
The following FST checks AI alarm status using the
FST logical command AND.
The FST reads the current AI alarm status value and
checks for a high alarm (bit weight = 4), high-high
alarm (bit weight = 8), and a point failure alarm (bit
weight = 64). The FST then activates a DO if any of the
alarms is active; otherwise, the FST deactivates the
DO.
Note that the value operated on by a logical command
must be read into the compare flag before the
command is executed, and saved out afterwards.
VAL
SAV
AND 76
VAL
!=
DO
GO
ALARM DO
DELAY WT
END
Arguments
None
• ARG1 = Database or Constant
Value
• ARG1 = Database or Constant
Value
• ARG1 = Database or Constant
Value
AIN E5, ALARM
FST 1, CMPFLG
FST 1, CMPFLG
0
DOU B4, STATUS
DELAY
DOU B4, STATUS
5
Results
• If SVD(in) > 0, SVD(out) = 0
• Otherwise, SVD(out) = 1
SVD(out) = [SVD(in) AND ARG1]
SVD(out) = [SVD(in) OR ARG1]
SVD(out) = [SVD(in) XOR ARG1]
ALARM
0
1
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