Determining Calibration Frequency; Digital Zero Trim - Emerson Rosemount 2088 Reference Manual

Operation and Maintenance
April 2021
5.4.4 Trimming with configuration buttons
Local configuration buttons are external buttons located underneath the top tag of the
transmitter. There are two possible sets of local configuration buttons that can be ordered
with the transmitter and used to perform trim operations: Digital zero trim and LOI. To
access the buttons, loosen screw and rotate top tag until buttons are visible.
• LOI (M4): Can perform both digital Sensor Trim and the 4–20 mA Output Trim (analog
output trim). Follow the same procedures listed in trimming with Field Communicator
or AMS Device Manager listed below.
• Digital zero trim (DZ): Used for performing a sensor zero trim. See
calibration frequency
All configuration changes should be monitored by a display or by measuring the loop
output.
Figure 5-1: Local Configuration Button Options
A. LOI - greeb retainer
B. Digital zero trim - blue retainer
5.5

Determining calibration frequency

Calibration frequency can vary greatly depending on the application, performance
requirements, and process conditions. Use the following procedure to determine
calibration frequency that meets the needs of your application.
Procedure
1. Determine the performance required for your application.
2. Determine the operating conditions.
3. Calculate the Total Probable Error (TPE).
4. Calculate the stability per month.
5. Calculate the calibration frequency.
5.5.1 Sample calculation for Rosemount 2088
Procedure
1. Determine the performance required for your application.
68
for trim instructions.
Figure 5-1 shows the physical differences between the two sets of buttons.
Required Performance: 0.50% of span
Rosemount 2088, 2090P, and 2090F Pressure Transmitter Reference Manual
Reference Manual
00809-0100-4108
Determining