4 .1
Calibration functions.
The
CAL1
and
CAL2
functions described below allow the display to be scaled to read in engineering units
using “live” inputs. For 4-20mA inputs and alternative method which does not require “live” inputs may be
used, see the
UsER En4
and
USER En20
functions which follow.
CAL1
(first scaling point for 2 point scaling method)
CAL1
and
CAL2
are used together to scale the instruments display, values for both must be set
when using this scaling method.
The
CAL1
function sets the first calibration point for live input calibration . When using this method
a “live” signal input must be present at the input terminals. Note:
CAL1
and
CAL2
can be set independently
i.e. it is not necessary to perform a
CAL2
operation directly after a
CAL1
.
The procedure for entering the first scaling point is:
a.
Ensure that an input signal is present at the input terminals, this will normally be at the low end of the
signal range e.g. 4mA for a 4-20mA input type.
b.
At the
CAL1
function press
^
and
v
simultaneously, then release them. The display will indicate
the live input value. Do not be concerned at this stage if the live input display value is not what is
required. It is important that the live input value seen is a steady value, if not then the input stability
needs to be investigated before proceeding with the scaling.
c.
Press, then release the
F
button. The display will indicate
SCL1
followed by a value. Use the
^
or
v
button to change this value to the required display scale value at this input. e.g. if 4mA was input and
the required display at 4mA was
0
then ensure
0
is selected at
SCL1
. Press the
F
button to accept
changes, the display will show
CAL End
and will then move on to the next function.
CAL2
(second scaling point for 2 point scaling method)
The second point scaling is performed in exactly the same manner as
CAL1
except that
SCL2
will
be seen instead of
SCL1
. It is essential that the live input is different in value to the
CAL1
input e.g. for a
4-20mA input use 20mA as the
CAL2
live input. Note; it is not essential that exactly 4 and 20mA are used as
the live inputs for a 4-20mA scaling but the input values must be significantly different.
The procedure for entering the second scaling point is:
a.
Ensure that an input signal (different to the input used at
CAL1
) is present at the input terminals, this
will normally be at the high end of the signal range e.g. 20mA for a 4-20mA input type.
b.
At the
CAL2
function press
^
and
v
simultaneously, then release them. The display will indicate
the live input value. Do not be concerned at this stage if the live input display value is not what is
required. It is important that the live input value seen is a steady value, if not then the input stability
needs to be investigated before proceeding with the scaling.
c.
Press, then release the
F
button. The display will indicate
SCL2
followed by a value. Use the
^
or
v
button to change this value to the required display scale value at this input. e.g. if 20mA was input
and the required display at 20mA was
500
then ensure
500
is selected at
SCL2
. Press the
F
button
to accept changes, the display will show
CAL End
and will then move on to the next function.
Page 15 of 46
LD4LNMAN-1.0-1
Input
Input
Displa
y v
alue
Displa
y v
alue
CAL2
CAL2
CAL1
SCL1
CAL1
SCL2
Setting CAL1
Setting CAL2
