Rosemount 2120, Reference Manual

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Reference Manual
00809-0100-4030, Rev DA
June 2007
Rosemount 2120
3-4
Replacement and Calibration of Electronic (PCB) Cassettes
When replacing a damage or faulty cassette, it is necessary to calibrate the cassette with
the operating frequency of the fork assembly. This is a list of actions required to enable
calibration to occur. Please make sure you understand them prior to starting. Calibration
sequence steps 3 to 13 are time dependent and must be carried out within the noted times.
The time dependency and switching sequence is to prevent an accidental calibration
occurring.
If this replacement is taking place in a (Potentially Explosive Atmosphere) Hazardous Area,
a suitably qualified person must carry it out. All work in hazardous areas must be carried out
in accordance to local code of practice. For general hazardous area requirements for this
equipment, refer to Appendix B: Product Certifications.
This calibration routine takes a bit of practice; do not be surprised if the unit does not
calibrate after the first attempt.
Replacement Sequence
On I.S. units, it is recommended that replacement and calibration be performed in a safe
(non-hazardous) area.
NOTE:
I.S. cassettes can only be replaced with I.S. cassettes.
Non-I.S. cassette types can be interchanged with other non-I.S. cassettes, but a new label
must be fitted and the original part number transferred to the new label.
Before starting the replacement and calibration procedure, ensure that any controlled
process will not be adversely affected.