Emerson Rosemount CT5800, Manual

Page: 54 / 192

2.4.4 Testing analog output cables
Prerequisites
In order to generate a 4-20 mA output, let the analyzer warm up for 90 minutes and make
sure the analysis cell is at the correct pressure.
The 4-20 mA outputs operate when the analysis cell is between 104 and 140 °F (40 and 60
°C) and the pressure is between 180 and 220 Torr. It is not essential to flow sample gas
through the system; nitrogen or atmospheric air is adequate for this test.
Procedure
With the analyzer at operating temperature and pressure, ensure that a current between
4 mA and 20 mA is generated on each 4-20 mA output, as listed in
Connecting the signal
cables .
Use a multimeter to measure the current.
2.4.5 Testing the measurement valid flag
The measurement flag is normally open contact. It is simplest to test this with a
multimeter.
With the analyzer closed and compressed air applied as described in the startup procedure
(
Startup procedure ) when the system is operating correctly, an open contact is created
between the two contact wires (white).
Procedure
To test the Error state, shut off the sample gas and allow the pump to reduce the cell
pressure below 180 Torr.
At this point, the contact should close and there should be no resistance between the two
white wires.
WARNING
FIRE AND EXPLOSION
In accordance with IEC 60079-0: 2011 Clause 30.
Failure to ensure the area is safe or leaving the device powered on can cause an explosion
or fire and serious injury to personnel.
Do not open the Ex d enclosure unless the area is known to be free of flammable materials
or unless all devices are switched off.
2.5 Closing the housing
After all internal connections have been made and proved/tested, close the enclosure and
secure the 20 off M16 x 45 captive screws and form A washers in accordance with the
torque sequence.
See Figure 2-11 .
Install Reference Manual
September 2019 00809-0100-5800
54 Emerson.com/Rosemount