Calibration
Procedure For 248/644/3144
Temperature Transmitter
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INDEX
1.
Purpose
2.
Scope
3.
General Safety & permit to work.
4.
Tools & Materials Required
5.
Calibration Procedures
6.
Shop calibration procedure
ABBREVIATIONS
1.
TT - Temperature
transmitter
2.
SMART - Signal
Modulated Addressable Remote Transducers.
3.
PPE - Personal
Protective Equipment.
4.
Non-IS - Non Intrinsic Safe.
5.
LRV - Lower Range
6.
URV - Upper Range
7.
HART - High way Addressable Remote
Transducer.
8.
DCS - Distributed Control System
9.
ILD -
Instrument Loop Drawing
10. RIB - Remote Instrument
Building
1.
Purpose
Ø
To provide a Standardized set of Guidelines for
the calibration of 248/644/3144
Temperature transmitter.
2.
Scope
Ø
This Calibration procedure is applicable for all
248/3144 SMART type Rosemount Temperature Transmitters.
3.
Permit
to Work & General safety
Ø
Obtain the necessary work permit.
Ø
Ensure appropriate PPE used.
Ø
Make sure whether any safety personal assistance
is required.
Ø
Make sure whether the concerned loop is related
to control or any trip systems, take necessary action before proceeding to
attend the transmitter.
4. Tools & Materials Required.
Ø Multimeter.
Ø Temperature
Calibrator.
Ø HART
communicator.
Ø Required
tools.
For oxygen service
use oxygen clean calibrator & oxygen clean tubes and fittings
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5.1. On line Hart communicator
Ø
Note down the transmitter range & unit from
master document in the work shop.
Ø
Before checking/adjusting the transmitter,
record the actual temperature indication in the control room.
Ø
Before proceeding to check the transmitter,
aware of the service conditions.
OXYGEN SERVICE
Ø Do not use stain gloves.
Ø Do not use oil & grease.
Ø Do not use Non –IS Calibrator and electronic
devices.
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Ø Ensure
the temperature is having Trip; follow the procedure for Trip Override.
Ø Ensure
sensor is Thermocouple / RTD.
Ø Remove
the sensor leads & insulate.
Ø Ensure
the grounding connection.
Ø Connect
the calibrator leads in the sensor terminals.
Ø Connect
the Hart communicator in transmitter loop terminals.
Ø Refer
HART menu tree for guidance.
Ø Select
Device Setup & enter
Ø Select Diag/ Service & enter
Ø Select Calibration & enter
Ø Select
sensor 1 trim & enter
Ø Select
sensor 1 Input trim & enter
Ø Set
the control loop manual & O.K
Ø Adjust
the calibrator to the desired lower
trim value.
Ø Select
O.K once the temperature stabilizes
Ø If
deviation is observed, do the Trim
procedure again.
Ø Adjust
the calibrator to the desired upper
trim value.
Ø Select
O.K once the temperature stabilizes
Ø If
deviation is observed, do the Trim
procedure again.
Ø Verify
the reading with control room operator.
Ø In
case of field mounted display is not applicable Ensure that the HART reading is
the same as calibrator reading.
Ø If
the accuracy is not with in the limits do the calibration again.
Ø Ensure
the power supply voltage to the
transmitter
Ø Repeat
the calibration and observe the repeatability of the transmitter readings in
the multimeter by up scale and down scale.
Accuracy is +/- 0.5 deg C for 248 Transmitter
Accuracy is +/- 0.12 deg C for 3144 Transmitter with RTD
sensor
Ø Record
all the calibration readings and transmitter manufacturer’s informations in the
calibration report.
Ø If
the loop under MANUAL or TRIP
override, observe the loop stability
And normalize
to auto and remove the trip Over ride.
Ø Close
the work permit.
Ø Submit
work order for supervisor approval and file the same.
Report to
supervisor if error is not with in the limits after calibration. Remove
transmitter to shop for further investigation.
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5.
Shop
Calibration Procedure
Ø Verify
the transmitter range & unit from master document in the work shop
Ø Clean
the transmitter.
Ø Connect
24Vdc from calibrator with 250 ohms loop resistance in series.
Ø Connect
multimeter in series with the transmitter.
Ø Connect
HART communicator and check LRV & URV.
Ø Apply
the temperature corresponding to LRV
and note down the mA in the multimeter.In case of any error, follow the
procedure in step 5.
Ø Apply
the temperature corresponding to URV
and note down the mA reading, In case of any error, follow the procedure in
step 5.
Report to
supervisor if error is not with in the limits after repeat calibration.
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Ø If
abnormal found, replace the transmitter or repair it accordingly
Ø Do
the calibration procedure again.
Ø Apply
temperature corresponding to intermediate values and note down the readings.
Ø Record
all the calibration readings and transmitter manufacturer’s informations in the
calibration report.
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