5.2
Adjustment resolution:
rE5n
This function enables the adjustment resolution of
the front panel
&
or
*
buttons and the optional al-
ternative external rotary control to be defined. One
of three different resolutions may be selected
1
,
10
or
100
least significant digits of the Set Point Station
display.
If
10
is selected the least significant dis-
played digit will always be zero and the second least
significant digit will change when the front panel
)
button plus the
&
or
*
button are pressed in the
operating mode, or the optional external rotary con-
trol is turned. Similarly, if
100
is selected the least
two significant displayed digits will always be zero
and the third least significant digit will change when
the front panel buttons are operated, or the optional
external rotary control is turned.
To define the adjustment resolution select
rE5n
from
the configuration menu and press
(
which will re-
veal the current adjustment resolution. To change
the resolution press the
&
or
*
button to select
1
,
10
or
100
, followed by the
)
button to enter the se-
lection and return to the configuration menu.
Notes:
a. This function does not affect the resolution of
adjustments
made
within
the configuration
menu.
b. If a pre-set output has a finer resolution than the
selected adjustment resolution, the finer resolu-
tion will be used to determine the pre-set output,
but the selected resolution will be restored when
the output is adjusted using the
)
button plus
the
&
or
*
button in the operating mode.
5.3
Position of the decimal point:
dP
A dummy decimal point can be positioned between
any of the displayed digits or it may be absent. To
position the decimal point, select
dP
from the config-
uration menu and press
(
.
The decimal point can
be moved by pressing the
&
or
*
push button. If
a decimal point is not required it should be posi-
tioned beyond the most or least significant digit.
When positioned as required press the
)
button to
enter the selection and return to the
dP
prompt in the
configuration menu.
5.4
Calibration of the digital display using an
external current meter:
CAL
This function is the preferred method of calibrating
the Set Point Station digital display to show the en-
gineering units represented by the 4/20mA output.
The function enables the Set Point Station output
current to be set at two different values, Zero and
Span, measured by a calibrated external current
meter and the corresponding Set Point Station dis-
play to be entered.
The bargraph is not displayed while using the
CAL
function.
Although
calibration
is
normally
performed
at
4.000mA and 20.000mA, other currents may be
used providing they differ by more than 4mA.
To calibrate the Set Point Station display, select
CAL
from the configuration menu and press
(
to enter
the
2Ero
sub-menu used for calibrating the display at
the lower of the two output currents, usually
4.000mA.
Pressing
(
again will result in ‘Adj’ be-
ing displayed which is an invitation to adjust the Set
Point Station output current using the
& or *
push
button. Pressing either of these buttons will cause
the output current to change, gradually accelerating
as the button is held. Alternatively the external rotary
encoder may be used. When the external current
meter shows the required lower output current e.g.
4.000mA, press
(
to reveal the existing Set Point
Station digital display with one digit flashing.
The
flashing digit may be adjusted by pressing the
&
or
*
button, when this digit is set as required
pressing
(
will transfer control to the next digit.
When all the digits have been adjusted, press
)
to
enter the setting and return to the
2Ero
prompt.
Calibration of the Set Point Station display at the up-
per output current is performed in exactly the same
way using the
5PAn
sub-menu which may be selec-
ted from the
2ero
prompt using the
&
or
*
button.
To obtain a reverse acting display i.e. the Set Point
Station display decreases as the output current in-
creases, the required display value entered into
2Ero
should be greater than that entered into
5PAn
.
The
&
or
*
buttons on the front of the instrument al-
ways indicate which way the display will change
when the button is pushed.
The bargraph will start at the numerical display
entered for
2Ero
calibration and finish at the numer-
ical display entered for
5Pan
calibration, except for
reverse acting calibration when the bargraph will also
be reversed.
Note:
a. If the specified
2Ero
and
5PAn
output currents
do not differ by 4 or more milliamps, they will not
be stored when the
)
button is pressed to re-
turn the Set Point Station to the operating mode.
5.5
Calibration of digital display using
internal reference:
5Et
Using the Set Point Station’s internal reference, this
function enables the digital display to be calibrated to
show the engineering units represented by the output
current at 4mA and 20mA.
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