Campbell CR10 PROM, Operator'S Manual

Page: 172 / 253

SECTION 12. PROGRAM CONTROL INSTRUCTIONS
12-3
Note that if the Output Flag is set prior to
entering the loop in the above example, 10
values will be output. The first will be the
average of all the readings in locations 1-10
since the previous output. Because the
Intermediate locations are zeroed each time an
output occurs, the next nine values will be the
current values (samples at the time of output) of
locations 2-10.
Loops can be nested. Indexed locations within
nested loops are indexed to the inner most loop
that they are within. The maximum nesting
level in the CR10 is 9 deep. This applies to If
Then/Else comparisons and Loops or any
combination thereof. An If Then/Else
comparison which uses the Else Instruction
(94) counts as being nested 2 deep.
PARAM. DATA
NUMBER TYPE DESCRIPTION
01: 4 Delay
02: 4 Iteration count
The following example involves the use of the
Loop Instruction, without a delay, to perform a
block data transformation.
The user wants 1 hour averages of the vapor
pressure calculated from the wet- and dry-bulb
temperatures of 5 psychrometers. One
pressure transducer measurement is also
available for use in the vapor pressure
calculation.
1. The input locations are assigned as follows:
a) pressure
Location 10
b) dry-bulb temperatures
Location 11-15
c) wet-bulb temperatures
Location 16-20
d) calculated vapor pressure
Location 21-25
(Vapor pressure is written over the
wet-bulb temperatures.)
2. The program flow is as follows:
a) Enter the Loop Instruction (#87) with
Delay=0 and iteration count=5.
b) Calculate the vapor pressure with
Instruction 57 using a normal location
entry of 10 for atmospheric pressure
and Indexed locations of 11, 16 and 16
for the dry-bulb, wet-bulb, and
calculated vapor pressure, respectively.