Safety Guide

XNX Universal Transmitter
Proof Test 8
Purpose of Proof Testing
5 Proof Test
5.1 Purpose of Proof Testing
A proof test is a periodic test to detect failures in the system so that,
if necessary, the system can be restored to an “as new” condition or
as close as practical to this condition.
5.2 Expected Outcome of Proof Testing
The following features are checked and adjusted if required
• current output at different levels (4.0 mA and 20.0 mA)
• verifying zero gas and span gas calibration current output
• verifying current output of warnings and faults
• simulating warnings and faults
• validation of the current output of zero gas and/or span gas
calibration (required if the current output of zero gas and/or
span gas calibration had to be changed)
5.3 Tolerance of Output Current Levels
The tolerance for the output current levels is ± 0.1 mA.
Example: If the procedure requires the current output to be 4.0 mA,
the actual current reading at the controller end can range from 3.9 mA
to 4.1 mA.
6 Proof Testing Procedure
6.1 Checking
The purpose of checking is to ensure the mA output meets the
expected levels. If the current does not meet the expected levels, it
will have to be adjusted. If, after completing 6.1.1, 6.1. 2 , and 6.1. 3, the
mA output does meet the expected levels, proceed to 6.3.
6.1.1 Force mA Output
1. Ensure the current can be measured at the controller end.
The current will be measured using the procedures outlined
in 6.1.1 to 6.1.3.
2. From the Main Menu, select the Test Menu (
).
CAUTION
The mA output set in this menu will revert to the normal operating
values when exiting the Test Menu. For more information on setting
the mA output levels for normal operation, see mA Levels in the XNX
Technical Manual.
3. From the Test Menu, select Force mA Output (
).
The New mA Output screen shows the existing mA output in
the left column. The user can adjust the output by changing
the value in the column on the right.
Figure 1. New mA Output Screen
4. Ensure the current at the controller end is 4.0 mA. If the current
is not 4.0 mA, refer to 6. 2.1 to adjust the output.
5. Repeat steps #2-4 to check the output of 20.0 mA.