Emerson Rosemount 2051 Reference Manual page 28

Section 2: Configure
April 2013
Rerange with an applied pressure source using local zero and span buttons
If ordered, local zero and span buttons (option code D4) can be used to rerange the transmitter
with an applied pressure. Refer to
location.
To rerange the transmitter using the span and zero buttons, perform the following procedure:
1. Loosen the screw holding the top tag of the transmitter housing. Rotate the label to expose
the zero and span buttons.
2. Confirm device has local zero and span buttons by verifying blue retainer under the tag.
3. Apply transmitter pressure.
4. Rerange the transmitter.
a.
b. To change the span (20mA/5V point) while maintaining the zero point: press and hold
Note
4mA and 20mA points must maintain the minimum span defined in
specifications
Figure 2-10. Analog Zero and span buttons
A. Zero and span Buttons



18
To change the zero (4mA/1V point) while maintaining the span: press and hold zero
button for at least two seconds then release.
the span button for at least two seconds and then release.
.
If the transmitter security is on, adjustments to the zero and span will not be able to be
made. Refer to "Configuring transmitter security" on page 59
The span is maintained when the 4mA/1V point is set. The span changes when the
20mA 5V point is set. If the lower range point is set to a value that causes the upper
range point to exceed the sensor limit, the upper range point is automatically set to the
sensor limit, and the span is adjusted accordingly.
Regardless of the range points, the Rosemount 2051 will measure and report all
readings within the digital limits of the sensor. For example, if the 4 and 20 mA(1-5 Vdc)
points are set to 0 and 10 inH
digitally outputs the 25 inH
Figure 2-10 on page 18 for analog zero and span button
A
O, and the transmitter detects a pressure of 25 inH
2
O reading and a 250% of range reading.
2
Reference Manual
00809-0100-4107, Rev BA
Appendix A: Functional
for security information.
O, it
2
Configuration