Maintenance, 1 overview, 2 calibration instruments selection – Yokogawa EJX430B User Manual

Page 66: 3 calibration, Maintenance -1, Overview -1, Calibration instruments selection -1, Calibration -1, Warning, Important

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<9. Maintenance>

9-1

IM 01C27B01-01EN

9. Maintenance

9.1 Overview

WARNING

Since the accumulated process fluid may be

toxic or otherwise harmful, take appropriate care

to avoid contact with the body or inhalation of

vapors when draining condensate or venting gas

from the transmitter pressure-detector section

and even after dismounting the instrument from

the process line for maintenance.

Maintenance of the transmitter is easy due to its

modular construction. This chapter describes the

procedures for calibration, adjustment, and the

disassembly and reassembly procedures required

for component replacement.
Transmitters are precision instruments. Please

carefully and thoroughly read the following sections

for information on how to properly handle them

while performing maintenance.

IMPORTANT

• As a rule, maintenance of this transmitter

should be done in a maintenance room that

has all the necessary tools.

• The CPU assembly, RF assembly and

Integral indicator contain sensitive parts that

can be damaged by static electricity.

Take precautions such as using a grounded

wrist strap when handling electronic parts or

touching the board circuit patterns. Also be

sure to place the removed CPU assembly,

RF assembly and Integral indicator into a

bag with an antistatic coating.

9.2 Calibration Instruments

Selection

Table 9.1 lists the instruments that can be used

to calibrate a transmitter. When selecting an

instrument, consider the required accuracy level.

Exercise care when handling these instruments to

ensure they maintain the specified accuracy.

9.3 Calibration

Use the procedure below to check instrument

operation and accuracy during periodic

maintenance or troubleshooting.
1) Insert the battery pack and then perform

provisioning to have the transmitter join the

Field Wireless Network or preparing the infrared

communication for calibration.

2) Set measurement mode to continuous using

the field device configuration tool and the

update period to 1 second using the field

wireless configuration tool.

3) Connect the devices as shown in Figure 9.1

and allow the transmitter to warm up for at least

5 minutes.

IMPORTANT

If the measurement range 0% point is 0 kPa

or shifted in the positive direction (suppressed

zero), the reference pressure should be applied

as shown in the figure.

If the measurement range 0% point is shifted

in the negative direction (elevated zero), the

reference pressure should be applied using a

vacuum pump.

4) Apply reference pressures of 0%, 50%,

and 100% of the measurement range to the

transmitter. Calculate the errors (differences

between the device configuration tool readings

and reference pressures) as the pressure is

increased from 0% to 100% and is decreased

from 100% to 0%, and confirm that the errors

are within the required accuracy.

(Note) When the output mode is set to “Sg root,” apply reference

pressures of 0, 6.25, 25, 56.25, and 100% instead.

5) When the test is finished, reset measurement

mode and update time to the initial value using

the field device configuration tool and the field

wireless configuration tool.

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