RKI Instruments 71-0533, Руководство оператора, Страница: 37 / 61

T3A Transmitter • 37
4. Press and release the MENU button to move through the Product Settings and
Configuration menu or to exit to the normal operating mode screen.
4-20 mA Offset Settings
Setting the 4-20 mA offset allows the end-user to calibrate the sensor’s analog output. Upon
installation of the device, if the detected gas reading on T3A does not correspond to the
reading on the controller, the zero offset (4 mA) and the full-scale offset (20 mA) can be
adjusted on the unit.
Over time, as electronic components suffer from normal wear and tear, the circuits will tend to
drift. This drift can cause variances in the amount of current output by the sensor, or in the
current measurement by the controller. If at any time the reading on the T3A no longer
matches the reading on the controller, the 4-20 mA offset will need to be recalibrated.
The factory default settings on the T3A for the 4-20 mA offset are 4.00 mA for the zero offset
and 20.00 mA for the full-scale offset.
1. If necessary, enter the Product Settings and Configuration menu by pressing and holding
the MENU button for 6 seconds.
2. Press and release the MENU button until the 4-20 mA Offset screen appears.
3. Press and release the ADD button to set the 4-20 mA offset and advance to the zero offset
setting screen. If you do not wish to set the 4-20 mA offset, press and release the SUB or
MENU button to advance to the display screen contrast setting screen.
Zero Offset Setting
If “Yes” is selected to set the 4-20 mA offset:
1. Use the ADD and SUB buttons to increase and decrease the zero offset on the unit,
respectively, until the controller reads 0 %/ppm, depending on the gas type being detected.
2. Press the MENU button to save the desired setting and to advance to the full-scale offset
setting screen.