2005 Cooper Industries, Inc.
6
S805
3/05
CONTACT PYROMETER MAINTENANCE
The contact pyrometers have been designed for accuracy, ease
of use and low cost. As with any pyrometer, certain guidelines
should be followed in order to obtain maximum precision of
measurement.
Prior to use, it is important that the wire ends (A) be inspected
and cleaned if necessary. Use a solvent such as alcohol and a stiff
brush to clean the wires. It is sometimes necessary to use a sharp
instrument to shave the burned flux off. After about eight hours of
actual use it will be necessary to either file or clip off the wire ends.
The wire should then be bent to maintain a gap (B) of .06". This will
restore the pyrometer to like new condition. This process may be
repeated as many times as the wire length will allow.
DISPLAY
CALIBRATION
1.
Set the analyzer rotary selector switch to
OHMS
.
2.
Connect a 100 ohm,
±
0.1%, resistor from the
TEST
receptacle to the
GND
receptacle.
3.
Measure voltage from pin 7 (+) to pin 8 (ground) of the ribbon cable (pin 1 of the
cable is nearest to the battery leads, see figure on page 7) and adjust R3 on the
display board until display and volt meter readings match, i.e., 1.000V = 100.0
ohms.
TEMPERATURE CALIBRATION
1.
Set the analyzer rotary selector switch to
TEMP
and the slide switch to
°
F
.
2.
Connect K-111 or K-181 thermocouple assembly to the
TEST
receptacle.
3.
Measure room temperature with a calibrated thermometer and record
temperature T
A
.
4.
Adjust R24 until display matches thermometer reading. Set the slide switch to
°
C
and adjust R85 until display reads the
°
C equivalent of room temperature, i.e., T
A
= 72
°
F = 22
°
C.
5.
Disconnect thermocouple assembly from the analyzer and set the slide switch to
°
F
.
6.
Using a precision millivolt power supply, input 22.251 mVdc (type K equivalent
voltage of 1000
°
F) to the
TEST
socket.
7.
Adjust R84 until display reads 1,000
°
F + (T
A
-32
°
F). For example, if room
temperature T
A
= 72
°
F then adjust display to read 1,000
°
F + (72
°
F - 32
°
F) =
1,040
°
F. Set slide switch to
°
C
and adjust R81 until display reads
°
C equivalent
of
°
F input, i.e., 1,040
°
F = 560
°
C.
