Ashcroft ZT12 Руководство по установке и обслуживанию - Страница 6

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Installation and Maintenance Instructions

for ZT12 High Purity Transmitter

Be sure to recalibrate the device using a set method or reca-

libration standards. Take special care not to effect the explo-

sion-proof performance of the instrument when inspecting in a

hazardous area.

The following is a routine inspection checklist

for your reference and use

Routine Inspection Checklist

• Physical appearance (scratches, cracks, warping,

corrosion, etc.)

• Corrosion status of pressure inlet

• Clogging of the air inlet

• Leak test for the connection points and re-tightening of

connecting screw

•

Check and tighten all instrument screws

•

Insulation resistance between each terminal and case

(at 100MΩ or more/50 Vdc or less)

• Output check by a pressure reference device and measuring

instrument

• Avoid electrostatic discharge.

• Use a soft cloth moistened with water to

only clean the external parts of the instru-

CAUTION:

ment. Do not use thinner, benzene, etc.

which cause deterioration and failure.

9.2 Adjustment

Remove the rubber plug (tethered plug) mounted at the side of

the enclosure.

• The rubber plug is equipped with a simple

tethering function, however if it is pulled

too strongly, it may be damaged. Please

CAUTION:

be careful not to use more force than

necessary [<17 in. lb.].

• Do not attempt adjustments if product is

wet. Do not allow water to enter the product

as this can lead to damage and/or

accidents.

• Make adjustments once the product has

been powered and allowed to warm up for

CAUTION:

15 minutes (recommended 30 minutes).

All sales subject to standard terms and conditions of sale. ZT12_Transducer_I&M011-10307_RevA_11-16-22

* !

• Zero and span adjustment are performed

by rotating zero/span potentiometer with

resin or ceramic Phillips screwdriver. Be

careful not to mistake the position and

CAUTION:

orientation of each adjustment.

• Avoid placing an excessive load [within 5N,

10 sec.] on the zero/span adjustment poten-

tiometer as this can lead to damage.

• Be extremely careful not to cause a short

circuit with the screwdriver.

• Use properly calibrated and traceable

instrumentation to verify adjustments.

(1) Zero adjustment

Zero adjustment is performed by rotating zero/span adjust-

ment potentiometer shown in the figure (Page 9) with Phillips

screwdriver.

Note: Refer to the following directions as the adjustment

method for absolute and compound ranged products differ.

[Positive pressure range]

Be sure that the applied pressure to the sensor has been

returned to atmospheric pressure (no pressure) state; adjust

the sensor output at this time to 4 mA dc.

[Compound range]

Be sure that the applied pressure to the sensor has been

released to atmospheric pressure (no pressure) state; adjust

the sensor output at this time to the value calculated by the

following:

• Output 4 to 20 mA dc (current output)

[Output mA DC in atmospheric pressure state] = [16 mA dc]

/ ([Upper limit output in range (MPa)] - [-0.1 MPa]) x 0.1 +

[4 mA dc]

e.g. (0.5MPa, Compound range: 6.67 mA dc) / (1.0 MPa,

Compound range: 5.45 mA dc)

(Absolute range)

At vacuum (using a vacuum pump or other means) adjust the

sensor output to the approximate output value based on the

degree of vacuum you are able to achieve. Approximately 4mA

• Avoid putting an excessive load, >44 in. lb.,

CAUTION:

10 sec., on the zero adjustment potentiome-

ters as this may result in damage.