MSA PrimaX - Page 50

General conditions for the safe use
• The application advice and the limitations of the manual have to be considered. For calibration and
maintenance, the regional and national regulations have to be considered.
• A defect transmitter has to be repaired within 72 hours.
• The HART
®
interface is not allowed to be used for the transmission of safety related data.
• The alarm conditions of the transmitter must be periodically checked together with the typical gas
calibration checks.
• The relays must be energised under normal conditions.
• The relay contacts must be protected with a fuse rated 0.6 of the nominal specified relay contact
current.
• The failure relay contacts must be safety related processed for warning purposes when the 4 to 20
mA link is not use for the alarm condition.
• The tests of the 4-20mA - output signal and alarm conditions and the test of the alarm and fault
relays, LEDs and display have to be done during calibration.
• The connected controller has to monitor the 4-20mA signal current for values below 4mA and
above 20mA.
• For the correct use of the combustible sensor a minimum oxygen concentration of 10Vol% is
necessary.
• The presence of catalytic poisons has to be avoided for the combustible sensor.
• A functional check/calibration check has to be done for the complete system.
• A visual check has to be done monthly.
• A system operation check has to be done every year.
• Calibration is only signaled on the 4-20 mA output by the service current. Therefore, the 4-20 mA
output shall be monitored at automatic calibration, if the sum of the application times parametrized
for zero gas and span gas application and the idle time exceeds 15 minutes, and at manual
calibration.
• For the test gas, the gas has to be used which is defined for the measurement. The concentration of
the test gas has to be in the middle of the measure range.
• For zero gas, synthetic air has to be used.
• An adjustment has to be done under the following conditions:
difference at zero > +/- 5% UEG
difference at sensitivity > +/- 20% of the rated value
• If the calibration is inside of the valid tolerance, the calibration interval can be doubled.
• The maximum of the calibration interval is 16 weeks.
• The sensor has to be replaced if the sensor sensitivity during the operation is reduced to less than
50 % of the initial sensitivity.
• After exposure of gas above the measuring range, the sensor has to be immediately
calibrated/adjusted, independent of the calibration interval. In the case of an adjustment the
sensitivity of the sensor has to be rechecked again after 24hours.
• If the appearance of catalytic poisons for the combustible sensor can not be avoided, the calibration
interval has to be considerably reduced.
GB PrimaX 50
7 Approvals