Fig 6a Installation into panel
Fig 6b Instrument wiring
5.3 EMC
The BA378C complies with the requirements of the
European EMC Directive. For specified immunity
all wiring should be in screened twisted pairs.
6. PROGRAMMING AND CALIBRATION
The BA378C is programmed and calibrated via four
front panel push-buttons. All the functions are
contained in two easy to use menus, the
Programme Menu and the Trim Menu, which are
shown diagramatically in Figs 7A, 7B and 9.
The Programme Menu contains all the transmitter
parameters and enables calibration to be
performed against the internal transmitter refer-
ences.
The Trim Menu enables the transmitter display and
the 4/20mA output current to be calibrated against
an external standard, such as a voltage source or
temperature calibrator. This is the preferred
method of calibration. A complete loop may be
calibrated using this menu to minimise errors result-
ing from primary element and load inaccuracies
.
Each function in the Programme Menu is summa-
rised in section 6.1 and includes a cross reference
to more detailed information in following sections.
Although this simple menu driven system enables
most adjustments to be made without repeated
reference to this manual, we recommend that the
summary of the programme menu, calibration
procedure using the trim menu and the calibration
example in sections 6.1, 7.1 and 8 are read prior
to changing function or calibrating the transmitter.
Figs 7A, 7B and 9 show the structure of the
menus.
Details of the Trim Menu are contained in section 7
which also describes 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 the
P
and
E
push-buttons simultaneously.
If the transmitter is not protected by a security
code the first parameter 'InPut' will be displayed. If
the transmitter is protected 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 flash-
ing 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 'InPut' to be displayed.
If an incorrect code is entered, or no button is
pressed for ten seconds, the transmitter will
automatically return to the operating mode.
When the transmitter is in the programme menu the
4/20mA output current will remain locked at the
value prior to starting programming, and it will
therefore not respond to any input change.
However, calibration of the 4/20mA output via the
'CAL' function, or re-calibration of the 4/20mA
references via the 'Cond' function will change the
output current.
Once within the Programme Menu the required
parameter can be reached by scrolling through the
functions using the
Up
and
Down
push-buttons as
shown in Figs 7A and 7B. When returning to the
display mode following changes to any parameters,
the transmitter will display four decimal points for a
few seconds while the new information is stored in
permanent memory.
9
