AMALGAMATED INSTRUMENT RM4-IV, Operation And Instruction Manual

Page: 34 / 49

6 Calibration
The instrument can be calibrated via a two point live input calibration method using functions
CAL1
and
CAL2
. For 4-20mA inputs only an alternative method allows display scaling without
live inputs using the
USER En4
and
USER En20
functions. An offset calibration scaling
adjustment using the
CAL OFSt
function is available which allows the scaling to be adjusted by
a fixed amount over the entire scale. Each of these methods and other calibration scaling function
are described in this chapter.
In order to gain access to the calibration functions you must be in
CAL
mode, refer to Chapter 5
page 17 which shows the method of entering
CAL
mode.
6.1 Live signal input calibration
CAL1
and
CAL2
- The functions
CAL1
and
CAL2
are used together to scale the instruments
display, values for both
CAL1
and
CAL2
must be set when using this scaling method. The
CAL1
function sets the first calibration point for live input calibration. When using this method different
signals inputs must be present at the input terminals for
CAL1
and
CAL2
. Note:
CAL1
and
CAL2
can be set independently.
The procedure for entering the first scaling point
CAL1
is as follows:
a. Ensure that an input signal is present at the input terminals, this will usually be at the low end
of the signal range e.g. 4mA for a 4-20mA input.
b. At the
CAL1
function press
^
and
v
simultaneously then release them. The display will show
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
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 value at this input. e.g. if 4mA was
input and the required display at 4mA was
0
then ensure
0
is entered at
SCL1
. Press the
F
button to accept changes or the
P
button to abort the scaling. If the scaling has been accepted
the
CAL End
message should be seen.
Input
Input
Displa
y v
alue
Displa
y v
alue
CAL2
CAL2
CAL1
SCL1
CAL1
SCL2
Setting
CAL1
Setting
CAL2
34 of 49 RM4IVMAN-2.1-0