BEKA BA304C Manual Download Page 10 | Manualshive

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BEKA BA304C Manual Download Page 10

10

7.4 Routine maintenance

The mechanical condition of the instrument and
the electrical calibration should be regularly
checked. The interval between inspections
depends upon environmental conditions. We
recommend that initially instrument calibration
should be checked annually.

7.5 Guarantee

Indicators which fail within the guarantee period
should be returned to BEKA associates or your
local BEKA agent. It is helpful if a brief description
of the fault symptoms is provided.

7.6 Customer comments

BEKA associates is always pleased to receive
comments from customers about our products and
services. All communications are acknowledged
and whenever possible, suggestions are
implemented.

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Summary of Contents for BA304C

Page 1: ...Issue 7 4th March 2014 BA304C Intrinsically safe loop powered 3 digit field mounting indicator Issue 7 ...

Page 2: ...Over and under range 7 Maintenance 7 1 Fault finding during commissioning 7 2 Fault finding after commissioning 7 3 Servicing 7 4 Routine maintenance 7 5 Guarantee 7 6 Customer comments 8 Accessories 8 1 Engraved scale and tag plates 8 2 Internal calibrator 8 3 Root extractor 8 3 1 Calibration example 8 4 Display backlight 8 4 1 Separately powered backlight 8 4 2 Loop powered backlight 8 5 Pipe mo...

Page 3: ...resistor R1 and forward biased diode D1 The voltage developed across D1 which is relatively constant is multiplied by a switch mode power supply and used to power the analogue to digital converter and liquid crystal display The voltage developed across R1 which is proportional to the 4 20mA input current provides the input signal for the analogue to digital converter Fig 1 Simplified block diagram...

Page 4: ... short time Be used with gases in groups Group A propane Group B ethylene Group C hydrogen Having a temperature classification of T1 450 C T2 300 C T3 200 C T4 135 C T5 100 C This allows BA304C indicators to be installed in all Zones and to be used with most common industrial gases WARNING installation in Zone 0 When installed in a Zone 0 potentially explosive atmosphere requiring apparatus of Cat...

Page 5: ... used only one barrier or channel may be a 28V 300ohm device Again it is necessary to ensure that the voltage capability of the 4 20mA signal is sufficient to drive the indicator plus the voltage drop introduced by the intrinsically safe interface Figs 3A 3B and 3C show the alternative circuits which may be used If one side of the 4 20mA current loop may be earthed a single channel Zener barrier p...

Page 6: ...uency screen in the GRP enclosure and to the case in the aluminium enclosure 5 2 Installation Procedure Fig 4 illustrates the instrument installation procedure a Remove the enclosure cover by unscrewing the four captive A screws b Remove the indicator assembly from the enclosure by unscrewing the three captive B screws c Mount the enclosure on a flat surface and secure with screws or bolts through...

Page 7: ...which allows rapid calibration without the need for exter nal instruments or disconnection from the 4 20mA input current See section 8 2 for details 6 1 Zero adjustment Zero is defined as the number displayed by the indicator with a 4 000mA input current and may be adjusted between 1000 and 1000 The zero potentiometer has two ranges 0 to 500 and 500 to 1000 Zero polarity is defined by the position...

Page 8: ...ecimal point A decimal point in position 00 0 The following adjustments are required Step 1 The BA304C is required to display a positive zero therefore the suppression elevation links should be put in the elevation position Step 2 The required zero is 250 therefore the zero link should be put in the 0 to 500 position Step 3 The required span is 900 therefore the span links should be placed in the ...

Page 9: ...display Indicator Check that the three with 4V assembly screws securing the between not correctly indicator assembly terminals 1 installed in are tightened and 3 enclosure Unstable 4 20mA Check loop supply display input has a voltage large ripple If this procedure does not reveal the cause of the fault it is recommended that the indicator assembly is removed from the enclosure and replaced This ca...

Page 10: ...libration should be checked annually 7 5 Guarantee Indicators which fail within the guarantee period should be returned to BEKA associates or your local BEKA agent It is helpful if a brief description of the fault symptoms is provided 7 6 Customer comments BEKA associates is always pleased to receive comments from customers about our products and services All communications are acknowledged and wh...

Page 11: ...in the 20mA position and adjust the indicator span potentiometer to give the required display at 20mA Step 4 Repeat steps 2 and 3 until both calibration points are correct The span and zero controls are almost independent so it should only be necessary to repeat each adjustment twice Step 5 Return the calibrator link to the indicate position The indicator will now respond to the 4 20mA input curre...

Page 12: ...isplay backlight The BA304C may be supplied with two different backlights The loop powered backlight produces green background illumination enabling the display to be read at night and in poor lighting conditions No additional power supply IS interface or field wiring are required but the indicator voltage drop is increased Alternatively the separately powered backlight has a bright orange output ...

Page 13: ...cklight may be connected in series with the BA304C indicator Any Zener barrier or galvanic isolator certified EEx ia IIC by an EEC approved certification body may be used providing the output parameters do not exceed Uo 30V dc Io 200mA Po 0 85W Fig 9 Loop powered backlight Connecting the backlight in series with the indicator will increase the total voltage drop in the 4 20mA loop from 1 1V to 5 0...

Page 14: ...Class I II and III Division 2 locations which allows it to be installed in Division 2 without the need for Zener barriers or galvanic isolators The maximum supply voltage must be less than 32V and the wiring must be nonincendive or Division 2 suitable as defined in the National Electrical Code ANSI NFPA70 A1 3 Classes Divisions Gas Groups and Temperature rating The indicator has been approved by F...

Page 15: ...capacitance and inductance of Ci 0 05µF Li 0 02mH These figures must be subtracted from the maximum permissible cable capacitance and inductance allowed for the Zener barrier or galvanic isolator powering the backlight A2 3 Nonincendive applications For nonincendive applications the separately powered backlight may be connected to a dc supply between 18 and 30V without the need for a Zener barrier...

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