BEKA BA484DF, Руководство пользователя

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be displayed in alternative units of measurement.
Display = (Gain x Fieldbus variable) + Offset
The sub-functions for each input are:
‘Offset’ Adds a positive or negative offset to
the fieldbus variable before it is
displayed.
‘Gain’ Multiplies the fieldbus variable by a
factor before it is displayed.
‘Bar Lo’ Defines the bargraph lower limit
*
‘Bar Hi’ Defines the bargraph higher limit
*
‘Format’ Defines the position of the displayed
decimal point.
*
Six options are available:
Auto: Max resolution with selected
display format.
4 DP 4 digits on right of decimal point
3 DP 3 digits on right of decimal point
2 DP 2 digits on right of decimal point
1 DP 1 digit on right of decimal point
0 DP No decimal point
*
These functions are not included when
‘Text Display’ is selected in the Screens
menu – see 6.3.1.
The total number of display digits available
depends upon the display screen selected – see
6.3.1
Standard
Screen Description Digits
1 1 variable 5, 7, 11 or 17*
2 2 variables 7
3 4 variables 5
4 1 va H bar 5, 7, 11 or 17*
5 2 var H bars 7
6 1 va V bar 6
7 2 varV bars 4
8 3 var V bars 6
9 4 var V bars 4
* Font automatically resizes in auto mode
If a negative number is likely to be displayed, a
digit must be allocated for the negative sign. If the
display overanges all the digits will display ‘?’.
For all options leading zeros are automatically
suppressed.
6.3.3 Tags
Only included in Profibus PA and Fieldbus
Foundation Revision 1 instruments. Omitted from
Fieldbus Foundation Revision 2 instruments
because tags can be easily defined in the Display
Transducer Block.
Each of the eight fieldbus variables may be
displayed with an individual tag that can contain
up to sixteen alphanumeric characters. This menu
allows these tags to be entered. After selecting
the required variable, the tag legend is entered
character by character using the
Up and Down
push-buttons. Numbers, upper & lower case
letters and symbols are available.
6.3.4 Units
Only included in Profibus PA and Fieldbus
Foundation Revision 1 instruments. Omitted from
Fieldbus Foundation Revision 2 instruments
because units of measurement can be easily
defined in the Display Transducer Block.
Each of the eight fieldbus variables may be
displayed with units of measurement that can
contain up to eight alphanumeric characters. This
menu allows these units of measurement to be
entered. After selecting the required variable, the
unit of measurement is entered character by
character using the
Up and Down push-buttons.
Numbers, upper & lower case letters and symbols
are available.
6.3.5 Alarms
Alarm menus are only included when the BA488CF
is fitted with optional alarm outputs.
Each of the six alarms may be linked to any one
of the eight fieldbus variables displayed by the
BA488CF. Each alarm output can be conditioned
to function as a high or a low alarm, or as a
combined high and low alarm. The output can be
conditioned as normally open ‘N/O’, or normally
closed ‘N/C’ in the non-alarm condition.
Irrespective of settings alarm outputs will be open
when the instrument is not powered from the
fieldbus.
When an alarm is activated, the associated
fieldbus variable display flashes, i.e. alternates
between dark figures on a light background and
light figures on a dark background.
There are eight alarm-conditioning sub-menus.
6.3.5.1 Alarm summary
Shows to which fieldbus variable each alarm is
linked and how each alarm has been conditioned
i.e. high, low, or combined high & low alarm with
normally open or closed output. No adjustments
can be made in this sub-menu.