5 pressure connection, 6 restrictions on use of radio transceivers, Pressure connection -3 – Yokogawa EJX530B User Manual

Page 11: Restrictions on use of radio transceivers -3, 5 pressure connection warning

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<2. Handling Cautions>

2-3

IM 01C27F01-01EN

2.5 Pressure Connection

WARNING

• Never loosen the process connector bolts

when an instrument is installed in a process.

The device is under pressure, and a loss of

seal can result in a sudden and uncontrolled

release of process fluid.

• When draining toxic process fluids that have

condensed inside the pressure detector,

take appropriate steps to prevent the contact

of such fluids with the skin or eyes and the

inhalation of vapors from these fluids.

The following precautions must be observed

in order to safely operate the transmitter under

pressure.
(a) Make sure that all the process connector bolts

are tightened firmly.

(b) Make sure that there are no leaks in the impulse

piping.

(c) Never apply a pressure higher than the

specified maximum working pressure.

2.6 Restrictions on Use of Radio

Transceivers

IMPORTANT

Although the transmitter has been designed to

resist high frequency electrical noise, if a radio

transceiver is used near the transmitter or its

external wiring, the transmitter may be affected

by high frequency noise pickup. To test this, start

out from a distance of several meters and slowly

approach the transmitter with the transceiver

while observing the measurement loop for noise

effects. Thereafter use the transceiver outside

the range where the noise effects were first

observed.

2.7 Insulation Resistance and

Dielectric Strength Test

Since the transmitter has undergone insulation

resistance and dielectric strength tests at the factory

before shipment, normally these tests are not

required. If the need arises to conduct these tests,

heed the following:
(a) Do not perform such tests more frequently than

is absolutely necessary. Even test voltages that

do not cause visible damage to the insulation

may degrade the insulation and reduce safety

margins.

(b) Never apply a voltage exceeding 500 V DC

(100 V DC with an internal lightning protector)

for the insulation resistance test, nor a voltage

exceeding 500 V AC (100 V AC with an internal

lightning protector) for the dielectric strength

test.

(c) The procedure for conducting these tests is as

follows:

• Insulation Resistance Test

1) Remove the battery pack. See subsection 9.4.5

for details on how to remove it.

2) Short-circuit the battery connection terminals in

the terminal box.

3) Turn OFF the insulation tester. Then connect

the insulation tester plus (+) lead wire to the

shorted battery connection terminals and the

minus (–) leadwire to the grounding terminal.

4) Turn ON the insulation tester power and

measure the insulation resistance. The voltage

should be applied as briefly as possible to verify

that the insulation resistance is at least 20 MΩ.

5) After completing the test and being very careful

not to touch exposed conductors disconnect the

insulation tester and connect a 100 kΩ resistor

between the grounding terminal and the short-

circuiting battery connection terminals. Leave

this resistor connected at least one second to

discharge any static potential. Do not touch the

terminals while it is discharging.

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