4
dISP
-
0C
,
0.0C
,
0F
,
0.0F
This program item sets the display for Fahrenheit or Celsius and whole
number or tenths. Tenths is not available for thermocouple types R, S, and B.
To change the display, use the “blank” button to scroll through the list of
choices. Press the “SEL” button to enter the choice and return to the main menu.
This menu item does not appear if
tYPE
=
LIN
.
FLtEr
-
0
,
1
,
2
,
3
If the displayed process signal is difficult to read due to small process
variations or noise, increased levels of filtering will help to stabilize the display.
Software filtering effectively combines a fraction of the current input reading
with a fraction of the previous displayed reading to generate the new display.
Filter values represent no filtering (0), up to heavy filtering (3). A value of 1
for the filter uses 1/4 of the new input and 3/4 of the previous display to generate
the new display. A filter value of 2 uses 1/8 new and 7/8 previous. A filter value
of 3 uses 1/16 new and 15/16 previous.
To select the filter level, use the “blank” button to scroll through the list of
choices. Press the “SEL” button to enter the choice and return to the main menu.
rANGE
-
00000
to
00099
The Range value selected determines if the filter, as set previously, will be
applied to the new input sample. If the new input value is within the ± range of
the previous display, the filter will be applied to the new input.
Example:
new input sample = 891 °C
previous display = 885 °C
range = 10 °C
885 ± 10 = 875 to 895 degree filter range based on previous display.
The new input sample (891 °C) is within ± 10 °C of the previous display
(885°C), so the filter is applied to the new input signal.
If the new input is outside the filter range, no filter is used. This allows fast
response to large signal changes and maximum filtering of small signal changes.
To enter the range value, use the “blank” button to increment the flashing
digit. To select a new digit, press the “SEL” button. After the desired value is
on the display, press and hold the “SEL” button for three seconds to enter the
value and return to the main menu.
OFSEt
- ±
00000
to
99999
The offset value is used to add or subtract a constant temperature from the
display. Typically this value should be zero. Changing this value does not affect
calibration, but will affect the displayed temperature. If a constant offset error is
occurring in the application, this feature may be used to reduce or eliminate
that error.
To enter an offset value, use the “blank” button to increment the flashing digit
or the sign of the number. To select a new digit or sign of the number, press the
“SEL” button. If no digits are flashing, use the “blank” button to toggle the sign
of the number or press the “SEL” button to wrap around to the LSD. After the
desired value is on the display, press and hold the “SEL” button for three
seconds to enter the value and return to the main menu.
CAL
-
YES
/
NO
Read the entire Calibration instructions before attempting to
calibrate the unit. Access codes are contained in the calibration
procedures. This unit is calibrated from the factory. Initial
calibration is not necessary. Calibration should only be performed
by individuals experienced in calibrating electronic equipment.
This item places the unit in calibration mode. Read the entire Calibration
section before attempting to calibrate this unit. If calibration is entered by
accident, press and hold the “SEL” button when the display shows
00000
for
access code. Approximately three seconds later the display will return to
tYPE
in the Program Menu.
To enter the Calibration Mode, use the “blank” button to change the
NO
to a
YES
. Press the “SEL” button to enter the choice.
CALIBRATING THE CUB4RT
The CUB4RT uses stored voltage and resistance calibration values to provide
accurate temperature measurements. Over time, the electrical characteristics of
the components inside the CUB4RT will slowly change with the result that the
stored calibration values no longer accurately define the input circuit. For most
applications, recalibration every 1 to 2 years should be sufficient.
Calibration of the CUB4RT involves a voltage calibration and a resistance
calibration. Allow 30 minute warm-up before performing any calibration related
procedure. The following procedures should be performed at an ambient
temperature of 15 to 35°C (59 to 95°F).
Calibration should only be performed by individuals experienced in
calibrating electronic equipment.
CAUTION: The accuracy of the calibration equipment will directly affect the
accuracy of the CUB4RT.
Calibration Check
1. Connect a precision resistance decade box with an accuracy of
±
0.01 ohms
to the unit as a three wire RTD.See Calibration Wiring Diagram All RTD
Wires should be the same length, gauge, and material. Keep wire length to a
minimum.
2. Verify that the unit is programmed for the correct RTD type.
3. Verify that the unit is programmed for a value of zero for
OFSEt
.
4. Verify that the input jumper is in the correct position.
5. Set the precision resistance decade box to the values shown below and verify
that the display reads accordingly.
±
0.9
°
C for Cu427, and
±
0.7
°
C for all
other RTD types.
Type
Jumper
282.6
20
259.0
379
852.5
391
850.3
396
231.3
18
252.5
370
815.2
380
797.3
380
180.1
16
213.8
320
619.9
320
607.1
320
128.5
14
170.1
270
437.9
260
429.3
260
76.7
12
120.7
220
266.4
200
261.4
200
25.0
10
64.9
170
104.0
140
102.1
140
-26.8
8
-0.0
120
-50.8
80
-49.9
80
-78.0
6
-74.8
70
-196.5
20
-193.2
20
-103.2
5
-80.9
66
-201.1
18
-200.1
17
°C
OHMS
°C
OHMS
°C
OHMS
°C
OHMS
Cu427
Pos A
Ni672
Pos B
Pt385
Pos B
Pt392
Pos B
