Operator`s manual

21X MICROLOGGER OVERVIEW
OV-6
Table 1.
Execute every x sec.
0.0125 < x < 6553
Instructions are executed
sequentially in the order
they are entered in the
table. One complete pass
through the table is made
each execution interval
unless program control
instructions are used to
loop or branch execution.
Normal Order:
MEASURE
PROCESS
CHECK OUTPUT COND.
OUTPUT PROCESSING
Table 2.
Execute every y sec.
0.1 < y < 6553
Table 2 is used if there is a
need to measure and
process data on a separate
interval from that in Table
1.
Table 3.
Subroutines
A subroutine is executed
only when called from
Table 1 or 2.
Subroutine Label
Instructions
End
Subroutine Label
Instructions
End
Subroutine Label
Instructions
End
FIGURE OV2-2. Program and Subroutine Tables
with an allowable range of 0.0125 to 6553
seconds. Intervals shorter than 0.1 seconds
are allowed only in Table 1. Subroutine Table 3
has no execution interval; subroutines are only
executed when called from Table 1 or 2.
OV2.3.1 THE EXECUTION INTERVAL
The execution interval specifies how often the
program in the table is executed, which is
usually determined by how often the sensors are
to be measured. Unless two different
measurement rates are needed, use only one
table. A program table is executed sequentially
starting with the first instruction in the table and
proceeding to the end of the table.
Each instruction in the table requires a finite
time to execute. If the execution interval is less
than the time required to process the table, the
21X overruns the execution interval, finishes
processing the table and waits for the next
execution interval before initiating the table.
When an overrun occurs, decimal points are
shown on either side of the G on the display in
the LOG mode (*0). Overruns and table priority
are discussed in Section 1.1.
OV2.3.2 THE OUTPUT INTERVAL
The interval at which output occurs is
independent from the execution interval, other
than the fact that it must occur when the table is
executed (i.e., a table cannot have a 10 minute
execution interval and output every 15 minutes).
A single program table can have many different
output intervals and conditions, each with a
unique data set (output array). Program Control
Instructions are used to set the Output Flag
which determines when output occurs. The
Output Processing Instructions which follow the
instruction setting the Output Flag determine the
data output and its sequence. Each additional
output array is created by another Program
Control Instruction setting the Output Flag high
in response to an output condition, followed by
Output Processing Instructions defining the data
set to output.
OV3. PROGRAMMING THE 21X
A program is created by keying it directly into the
datalogger or on a PC using the PC208
Datalogger Support Software program EDLOG.
This manual describes direct interaction with the