Campbell Scientific CR23X Micrologger - Manual (Page 89)

7-1
SECTION 7. MEASUREMENT PROGRAMMING EXAMPLES
This section gives some examples of Input Programming for common sensors used with the CR23X.
These examples detail only the connections, Input, Program Control, and Processing Instructions
necessary to perform measurements and store the data in engineering units in Input Storage. Output
Processing Instructions are omitted. It is left for the user to program the necessary instructions to obtain
the final data in the form desired. NO OUTPUT TO FINAL STORAGE WILL TAKE PLACE WITHOUT
ADDITIONAL PROGRAMMING.
The examples given in this section would likely be only fragments of larger programs. In general, the
examples are written with the measurements made by the lowest numbered channels, the
instructions at the beginning of the program table, and low number Input Storage locations used to
store the data. It is unlikely that an application and CR23X configuration exactly duplicates that
assumed in an example. THESE EXAMPLES ARE NOT MEANT TO BE USED VERBATIM;
SENSOR CALIBRATION AND INPUT LOCATIONS SELECTED MUST BE ADJUSTED FOR THE
ACTUAL CIRCUMSTANCES. UNLESS OTHERWISE NOTED, ALL EXCITATION CHANNELS ARE
SWITCHED ANALOG OUTPUT.
7.1 SINGLE-ENDED VOLTAGE/
SWITCHED 12 V TERMINAL - CS500
The CS500 is a modified Vaisala 50Y Humitter
temperature and relative humidity sensor. It
has high level linear output of 0 to 1 V for the
temperature range of -40
°
to +60
°
C and relative
humidity of 0 to 100%. It is measured with
Instruction 1 (Volts SE). The multiplier for
temperature is found with the following
relationship [60°C - (-40°C)] / [1000 mV - 0 mV]
= 0.1°C/mV. The offset is -40°C. The multiplier
for relative humidity is [100 % - 0 %] / [1000 mV
- 0 mV] = 0.1 %/mV and the offset is 0 %. The
CS500 is powered by the CR23X’s 12 V battery
and draws <2 mA of current while on. Battery
power can be conserved by turning the CS500
on just prior to making the measurement and
turning it off after the measurement is
completed. This is done with the Switched 12 V
terminal on the CR23X wiring panel.
CONNECTIONS
The CS500 output is measured using two
single-ended voltage measurements on analog
inputs 5 and 6. Single-ended analog inputs are
labeled in blue on the CR23X wiring panel. A
wiring diagram on connections between the
CR23X and the CS500 is given in Figure 7.1-1.
CAUTION: The Switched 12 V Control
terminal will be permanently damaged if 12
V is applied to it. Do not connect 12 V to
the Switched 12 V Control terminal.
PROGRAM
;Turn CS500 on.
;
01:
Do (P86)
1: 49
Set Switched 12 V High
;Allow CS500 to warm up and stabilize on
;the Temperature and Relative Humidity.
;
02:
Excitation with Delay (P22)
1:
3 Ex Channel
2: 0 Delay W/Ex (units = 0.01 sec)
3: 10 Delay After Ex (units = 0.01 sec)
4: 0 mV Excitation
;Measure Temperature.
;
03:
Volts (SE) (P1)
1:
1 Reps
2: 25
±
5000 mV Slow 60 Hz
Rejection Range
3: 5 SE Channel
4: 1 Loc [ Temp_C ]
5: .1 Mult
6: -40 Offset