Operator`s manual

SECTION 3. INSTRUCTION SET BASICS
3-4
set high. This flag is used to restrict sampling
for averages, totals, maxima, minima, etc., to
times when certain criteria are met. The flag is
automatically set low at the beginning of the
program table.
As an example, suppose it is desired to obtain a
wind speed rose incorporating only wind speeds
greater than or equal to 4.5 m/s. The wind
speed rose is computed using the Histogram
Instruction 75, and wind speed is stored in Input
location 14, in m/s. Instruction 89 is placed just
before Instruction 75 and is used to set Flag 9
high if the wind speed is less than 4.5 m/s:
TABLE 3.7-2. Example of the Use of Flag 9
Inst. Param.
Loc. No. Entry Description
X P 89 If wind speed < 4.5 m/s
1 14 Wind speed location
2 4 Comparison: <
3 4.5 Minimum wind speed
for histogram
4 19 Set Flag 9 high
X+1 P 75 Histogram
X+2 P 86 Do
1 29 Set Flag 9 Low
NOTE: Flag 9 is automatically reset
the same as Flag 0. If the
intermediate processing disable flag
is already set high and the test
condition of a subsequent Program
Control Instruction acting on Flag 9
fails, the flag is set low. This feature
eliminates having to enter another
instruction to specifically reset Flag 9
before proceeding to another group
of test conditions.
3.7.3 USER FLAGS
Flags 1-8 are not dedicated to a specific
purpose and are available to the user for
general programming needs. The user flags
can be manually toggled from the keyboard in
the *6 Mode (Section 1.3) or from a computer
using TERM's monitor feature. By inserting flag
tests (Instruction 91) at appropriate points in the
program, the user can manually set flags to
direct program execution.
3.8 PROGRAM CONTROL LOGICAL
CONSTRUCTIONS
Most of the Program Control Instructions have a
command code parameter which is used to
specify the action to be taken if the condition
tested in the instruction is true. Table 3.8-1 lists
these codes.
TABLE 3.8-1. Command Codes
0 - Go to end of program table
1-9, 77-99 - Call Subroutine 1-9, 77-99
10-19 - Set Flag 0-9 high
20-29 - Set Flag 0-9 low
30 - Then Do
31 - Exit loop if true
32 - Exit loop if false
41-46 - Set port 1 - 6 high
51-56 - Set port 1 - 6 low
61-66 - Toggle port 1 - 6
71-76 - Pulse port 1 - 6 100 ms
3.8.1 IF THEN/ELSE COMPARISONS
When Command 30, THEN DO, is used with
one of the IF Instructions, 88-92, the instruction
is followed immediately by instructions to
execute if the comparison is true. The Else
Instruction, 94, is optional and is followed by the
instructions to execute if the comparison is
false. The End Instruction, 95, marks the end
of the branching started by the IF Instruction.
Subsequent instructions are executed
regardless of the outcome of the comparison
(Figure 3.8-1).
FIGURE 3.8-1. If Then/Else Execution
Sequence