Campbell Scientific CR7 Measurement and Control System User Manual
Page 123
SECTION 12. PROGRAM CONTROL INSTRUCTIONS
12-5
PAR.
DATA
NO.
TYPE
DESCRIPTION
01:
2
Increment for the loop index
counter
*** 91 IF FLAG ***
FUNCTION
This instruction checks one of the ten flags and
conditionally performs the specified command.
The first parameter specifies the flag to check
and the flag status (high or low) on which to
execute the command.
1X = execute Command if Flag X is high
2X = execute if Flag X is low
PAR.
DATA
NO.
TYPE
DESCRIPTION
01:
2
Flag/status
02:
2
Command (Table 12-2)
*** 92 IF TIME ***
FUNCTION
The user specifies the number of minutes into
an interval, the duration of the interval, and a
command. The command is executed each
time the real time is the specified number of
minutes into the interval.
The time interval is synchronized with real time;
if a 60 minute time interval is specified with 0
minutes into the interval, the Command will be
executed each hour on the hour. The time
interval is automatically synchronized by making
a modulo divide of the number of minutes since
midnight by the specified real time interval. If
the result is 0, the interval is up. Thus, the first
interval of the day always starts at midnight (0
minutes). Only one execution is allowed in any
minute (e.g., if the command is to set the
Output Flag, and the execution interval of the
table is ten seconds, there will only be one
output generated by this instruction, not six.)
The Output Flag (Flag 0) is a special case in
that it will automatically be set low if it is not time
to set it high.
PAR.
DATA
NO.
TYPE
DESCRIPTION
01:
4
Time into interval (minutes)
02:
4
Time interval (minutes)
03:
2
Command (Table 12-2)
*** 93 BEGIN CASE STATEMENT ***
Instruction 93 specifies an input location for
comparison with fixed values in subsequent If
Case instructions (83). When a comparison is
true, the command in the If Case instruction is
executed and at the next Instruction 83
execution jumps to the End Instruction 95
associated with the Begin Case Instruction.
PAR.
DATA
NO.
TYPE
DESCRIPTION
01:
4
Input location for subsequent
comparisons
EXAMPLE:
01:
P93
Case
01:
2
Case Loc
02:
P83
If Case Location < F
01:
69.4
F
02:
3
Call Subroutine 3
else
03:
P83
If Case Location < F
01:
72
F
02:
10
Set high Flag 0 (output)
else
04:
P83
If Case Location < F
01:
77.3
F
02:
30
Then Do
05:
P30
Z=F
01:
0
F
02:
0
Exponent of 10
03:
25
Z Loc :
06:
P95
End
Then Do
07:
P95
End
of Case
Statement
*** 94 ELSE ***
FUNCTION
When Command 30 (Then/Else) is used with an
If Instruction, the Else Instruction is used to
mark the start of the instructions to execute if
the test condition is false (Figure 3.8-1). The