5.3.1 Humidity Calibration at 33% Humidity
1.
Set up the recorder with the temperature/humidity sensor in a sealed jar (33% RH) using
saturated magnesium chloride as shown in Figure 5-5. If you are not experienced with
saturated salt solutions, you may not obtain good results. If you are experiencing difficulty,
contact our Engineering Department.
2.
After the probe reading reaches equilibrium (after 1 hour), take a reading.
CASE 1:
The 33% reading is too low by
n
counts, so DECREASE the humidity
code by n counts.
EXAMPLE 1:
you obtain a reading of 31%. The error is -2 since 31 is 2 counts lower than
33%. The initial humidity code of 87 (in this example) must be reduced to 67 (–2 counts).
READING
INITIAL
ERROR
CHANGED (NEW) HUMIDITY
IN 33%
HUMIDITY
CODE
CODE IN 33% “HUMID”
ENVIRONMENT
CODE
ENVIRONMENT
31
8
7*
-2
6
7*
* the first digit is flashing and changes in this case.
CASE 2:
The 33% reading is too high by
n
counts, so INCREASE the humidity
code by n counts.
EXAMPLE 2
: you obtain a reading of 37%. The error is +4 since 37 is 4 counts higher
than 33%. The initial humidity code of 65 in this example must be increased to A5
(+4 counts; A comes after 9).
READING
INITIAL
ERROR
CHANGED (NEW) HUMIDITY
IN 33%
HUMIDITY
CODE
CODE IN 33% “HUMID”
ENVIRONMENT
CODE
ENVIRONMENT
37
6
5*
+4
A
5*
* the first digit is flashing and changes in this case.
3.
Change the first digit before proceeding to the next step, since a change in the first digit
affects readings throughout the range. Go through Section 5.1 to set the calibration codes in
the recorder. Then recheck to see that the reading is 33. If it is not, adjust the first digit of the
code again. After pressing the “SET” button, the second digit will start flashing.
4
Next, place the probe in a saturated salt environment of 75% RH using NaCl.
5.
After the probe equalizes (after 1 hour), take a reading (the second digit displayed may have
changed).
6.
Continue to Section 5.3.2.
Calibrating the Recorder
5
5-6
Summary of Contents for CT485B-110V-G-AL
Page 23: ...Setting Up the Recorder 2 2 14 Notes...
Page 27: ...Powering Up the Recorder 3 3 4 Notes...
Page 33: ...Alarm Operation 4 4 6 Notes...
Page 43: ...Using the Cal Lock Kit 6 6 2 Notes...
Page 45: ...Using the Voltage Input Adapter Optional 7 7 2 Notes...
Page 49: ...8 4 Notes Maintaining the Recorder 8...
Page 57: ...Specifications 11 11 4 Notes Notes...
Page 59: ...CE Approval 12 Notes 12 2...
