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BEKA BA378C Скачать руководство пользователя страница 27

11.4 Adjusting the alarm setpoints from the

display mode.

Access to the alarm setpoint when the BA378C
transmitter is in the display mode is obtained by
operating the

P

and

Up

push-buttons simultane-

ously - see Fig 14. If the setpoints are not
protected by a security code the alarm setpoint one
'SP1' will be displayed. If the setpoints are
protected by a security code, 'COdE' will be
displayed first. Pressing

P

again will enable the

alarm security code to be entered digit by digit
using the

Up

and

Down

buttons to change the flash-

ing digit, and the

P

push-button to move to the next

digit. If the correct code is entered pressing

E

will

cause alarm setpoint one 'SP1' to be displayed.
Pressing the

Up

or

Down

button will toggle the

display between 'SP1' and 'SP2'.

Fig 14 Setpoint adjustment from display mode

If an incorrect code is entered, or a button is not
pressed for ten seconds, the transmitter will
automatically return to the display mode.

To adjust an alarm setpoint select 'SP1' or 'SP2'
and press

P

which will reveal the current setting.

Each digit of the setpoint may be adjusted using the

Up

and

Down

push-buttons, and the

P

button to

move to the next digit. When the required setpoint
has been entered, pressing

E

will return the

display to the 'SP1' or 'SP2' prompt from which the
other setpoint may be selected, or the transmitter
may be returned to the display mode by pressing

E

again.

Direct access to the alarm setpoints is only avail-
able when the menu is enabled - see section 11.3.8

12. BACKLIGHT

The BA378C can be supplied with LED backlighting
to improve display contrast when the transmitter is
installed in a poorly illuminated area. This is
segregated from the measuring circuit and has
been certified as a separate intrinsically safe
circuit.

The backlight must be powered from the safe area
via a Zener barrier or a galvanic isolator as shown
in Fig 15. Any certified EEx ia IIC device may be
used, providing the output parameters do not
exceed:

Uo

=

30V dc

Io

=

159mA

Po

=

0.85W

For guidance, the system certificates list some
devices which may be used.

Fig 15 Backlight power supply

The display brilliance depends upon the current
flowing through the backlight which is determined
by the supply voltage and the end-to-end resistance
of the Zener barrier or output resistance of the
galvanic isolator. Brilliance will not be significantly
reduced until the current falls below 20mA.

Backlight current = Vsupply -18
End-to-end resistance of barrier

#

# or output resistance of galvanic isolator

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Содержание BA378C

Страница 1: ...BA378C Intrinsically safe panel mounting indicating temperature transmitter issue 6 Issue 6 25th September 2008 ...

Страница 2: ...isplay calibration 6 6 4 20mA output current calibration 6 7 Security code 6 8 Calibrating the internal references 6 8 1 Conditioning internal references 6 8 2 Voltage input reference 6 8 3 3 wire RTD reference 6 8 4 4 wire RTD reference 6 8 5 Output current reference 7 Trim Menu 7 1 Calibration procedure using Trim Menu 7 2 Periodic re calibration using Trim Menu 8 Calibration example 9 Maintenan...

Страница 3: ...ions of Section 6 you will find information on setting up for Section 6 3 Thermocouple input Section 6 4 Resistance thermometer input Section 6 5 Voltage input A word of warning Section 6 8 explains how you can calibrate the instrument s internal references It is only necessary to carry out this operation if you will be using these internal references to calibrate the instrument display i e not us...

Страница 4: ...4 ...

Страница 5: ...lies linearisation using look up tables stored in permanent memory The resulting temperature is shown on the internal display and controls the 4 20mA output current The transmitter and the optional alarms are powered from the 4 20mA current loop but the optional display backlight requires a separate supply Each time power is applied to the instrument initialisation is performed After a short delay...

Страница 6: ...gases in groups Group A propane Group B ethylene Group C hydrogen Having a temperature classification of T1 450o C T2 300o C T3 200o C T4 135o C T5 100o C This allows the BA378C to be installed in all Zones and to be used with most common industrial gases at ambient temperature between 40 and 60o C Note minimum operating temperature is 20o C 3 4 Certification information label The certification in...

Страница 7: ...is earthed at the barrier busbar Fig 2 BA378C powered from floating supply If a common power supply is used to operate more than one loop the negative side of the supply is normally connected to earth To enable the negative side of the 4 20mA load also to be earthed it is necessary to have a Zener barrier in each wire going into the hazardous area as shown in Fig 3 Any certified diode return barri...

Страница 8: ... the instrument and the panel The trans mitter must be positioned such that the environ mental conditions specified by the instrument datasheet and the EC Type Examination Certificate are not exceeded and it will not be attacked by aggresive substances Please consult BEKA associates if the instrument is to be installed in an area subject to high vibration Fig 5 shows the overall dimensions of the ...

Страница 9: ...ribes periodic calibration When the transmitter is fitted with alarms additional functions are added to the programme menu These are described in section 11 of this manual Throughout this manual push buttons are shown in italics e g P or Up push button and legends displayed by the transmitter are shown within inverted commas e g CAL and ALr2 Access to the Programme Menu is obtained by operating th...

Страница 10: ...10 ...

Страница 11: ...11 ...

Страница 12: ...ation Figs 7A and 7B illustrate the location of each function within the menu Display Summary of Programme Menu functions InPut Transmitter input Conditions the transmitter to accept thermocouple tHC resistance thermometer rtd or a voltage UOLt input See section 6 2 1 Display Summary of Programme Menu functions For Thermocouple Inputs tYPE Sensor type Selects the type of thermocouple input See sec...

Страница 13: ...programme structure shown in Figs 7A and 7B 6 2 1 Transmitter input InPut This function conditions the transmitter to accept a thermocouple tHC resistance thermometer rtd or a voltage UOLt input To define the transmitter input select InPut from the Programme Menu and press P which will reveal the current setting This setting may be changed by scrolling through the menu using the Up or Down buttons...

Страница 14: ...rrent setting The setting may be changed by pressing the Up or Down button When the required setting has been selected press E to return to the sub menu 6 4 For resistance thermometer inputs 6 4 1 Types of resistance thermometer tYPE The transmitter may be conditioned to accept 3 wire 4 wire or differential Pt100 resistance thermometers After selecting resistance thermometer input from the InPut s...

Страница 15: ...y The calibration is performed using the internal references and may be made with any transmitter input voltage Select In HI from the menu and press P which will access a sub menu containing two functions InPut and dISP Select the input voltage InPut and press P which will cause the specified higher input millivoltage to be displayed in the form XX XX The flashing digit of the input voltage can be...

Страница 16: ...ty link in the override position see Fig 8 The security code can then be viewed by selecting COdE from the menu and pressing P To access the security code link un plug the removable terminal s from the rear of the instrument by gently pulling and remove the instrument rear panel which is secured by six screws The link can then be moved to the override positioned as shown in Fig 8 Fig 8 Location of...

Страница 17: ...dard resistor or calibrator with the compensation loop remaining connected between terminals 3 and 4 It is preferable to make this substitution as close to the RTD as possible but transmitters may be calibrated in a workshop Select 3rtd from the Cond sub menu and press P The transmitter will display scrolling decimal points while the reference is being updated followed by Ent prior to returning to...

Страница 18: ...tected by a security code COdE will be displayed first Pressing P again will enable the security code to be entered digit by digit using the Up and Down buttons to change the flashing digit and the P push button to move to the next digit If the correct code is entered pressing E will cause the first parameter ZEro to be displayed If an incorrect code is entered or if no button is pressed for ten s...

Страница 19: ...s are used to make frequent calibration changes we recommend that these references should be initially checked once per year as described in sections 6 8 1 to 6 8 5 If the BA378C is always calibrated with an external reference such as a voltage source using the trim menu it will not be necessary to check the internal references 8 CALIBRATION EXAMPLE In this example a BA378C is required to display ...

Страница 20: ...yed press E to store the conditioning and calibration information and return to the display mode All the display decimal points will be activated while the information is being stored This completes the calibration of the transmitter using the internal references The following steps explain how using the Trim Menu the BA378C transmitter may be calibrated against an external reference such as a vol...

Страница 21: ...rn the transmitter to the SPAn prompt This completes calibration at 240 0o C Pressing the E push button again will return the transmitter to the display mode 9 MAINTENANCE The instrument should only be maintained by trained competent personnel 9 1 Fault finding during commissioning If the BA378C transmitter fails to function during commissioning the following procedure should be followed Symptom C...

Страница 22: ... hold a card showing the units of measurement e g o C o F kg The transmitter can be supplied with a printed scale card showing any units specified at time of ordering If a printed scale card is not requested a blank card will be fitted Scale cards can easily be marked on site as follows a Un plug the rear terminal block s disconnect the input wires and remove the rear panel which is secured by fou...

Страница 23: ... output parameters of the circuit do not exceed Uo 30V dc Io 280mA Po 0 85W The maximum equivalent capacitance and inductance between each set of alarm terminals is Ceq 40nF Leq 20µH These figures must be subtracted from the maximum permitted cable capacitance and inductance specified by the system certificate of the circuit connected to the alarm Fig 12 Typical application of alarms 11 1 3 Progra...

Страница 24: ...ltering any of the alarm parameters To check or change the function select EnbL from the alarm sub menu and press P which will reveal the current setting The function may be changed by pressing the Up or Down button followed by the E button to return the EnbL prompt 11 3 2 Setpoint adjustment SP1 and SP2 The setpoint of each alarm relates to the transmitter display and each may be independently po...

Страница 25: ...25 ...

Страница 26: ...3600 seconds in 1 second increments To adjust the alarm silence time select SIL from the alarm sub menu and press P which will reveal the existing time Each digit may be adjusted using the Up and Down push buttons and the P button to move to the next digit When the required time has been entered press E to return the SIL prompt 11 3 8 Access Setpoint AcSP This function controls the parameters in a...

Страница 27: ...he next digit When the required setpoint has been entered pressing E will return the display to the SP1 or SP2 prompt from which the other setpoint may be selected or the transmitter may be returned to the display mode by pressing E again Direct access to the alarm setpoints is only avail able when the menu is enabled see section 11 3 8 12 BACKLIGHT The BA378C can be supplied with LED backlighting...

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