Omega RD260A - Manual (Page 39)

4 - 14
Calibration is a comparing operation between standard inputs and measured values.
It is recommended to carry out a calibration once a year to assure the measuring
accuracy.
Required instruments for calibration
The instruments for calibration should have the required resolution. If necessary, ask
the sales office from whom you purchased the recorder about those instruments.
Recommended instruments
OMEGA model # CL511 calibrator
Calibration procedure
(1) Connect the instruments to the recorder; connecting the terminals is shown below.
Give enough warm-up time to the instruments (more than 30 minutes for the
recorder).
(2) Check that the ambient temperature and humidity are within the standard operating
conditions.
Standard operating conditions
Ambient temperature : 23±2˚C
Humidity
: 55±10% RH
Power supply : 90 to 132 V AC, or 180 to 250 V AC
Power frequency : 50/60 Hz±0.1%
Warm-up time : 30 minutes or more
Mechanical vibration : Within the range not affecting recorder operation
However, when the calibration is conducted under normal operating conditions (see subsection 4.8.6),
check the accuracy influenced by the conditions.
Chart paper yields thermal expansion or shrinkage, sometimes resulting in differences from the
calibrated values.
Examples of expansion are shown below assuming the reference temperature 20˚C and humidity 65% RH:
Expansion at 85% RH ..... 0.4% or less
Expansion at 35% RH ..... 0.45% or less
(3) Input the standard signals equivalent to 0, 50, and 100% of the setting range of the
recorder, then check the difference error between input signals and measured
values.
If the error is not within the specified accuracy, contact OMEGA Engineering.
NOTE A reference input for a thermocouple (TC) signal needs temperature
compensation; the temperature at the recorder input terminal should be
measured to make voltage compensation (adding) due to the reference junction
temperature compensation.
Input terminals
(for DC Voltage or TC)
Power terminals
DC voltage standard
L
N
1
2
3 +
–
–
+
DC Voltage Signal for Pen model (same as Dot-printing model)
Temperature Measurement for Resistance Temperature Detector (RTD)