Dissolved Oxygen Controller Operation
Teledyne Analytical Instruments 41
4mA1 trim .000
4 to 20 mA trim
The bottom line shows the measured temperature. To change the
displayed temperature so it agrees with a measured value, place the
cursor on the top line then simultaneously depress both CALIBRATE
◄/ ► keys. Use the right-side CALIBRATE ▲/▼ keys to adjust the
number so that the displayed temperature agrees with that measured by a
thermometer.
The number shown on the top line is simply added to the
temperature that the instrument measures. There is no slope correction.
To toggle between degrees C and degrees F, place the cursor on the
bottom line and simultaneously depress both CALIBRATE ◄/ ► keys.
This will change the unit. Press both keys again to toggle back to the
original unit.
All temperature displays on both channels use the selected system
of units. The scale and units code in the HART temperature output is
also controlled by this selection.
On two channel instruments the next display trims the channel 2
temperature.
3.3.7 4-20 Trim
The next six displays are used to trim the 4-20 outputs. The 4-20
outputs are calibrated at the factory and will never need recalibration in
most applications. Periodic recalibration is not recommended.
As in the other menus, the cursor moves to the right when both
CALIBRATE keys are depressed and the output current is set to 4.00
mA, overriding the output assignment. Measure the 4-20 output #1
current with an ammeter, and adjust the number on the top line until the
meter reads 4.00 mA.