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5.3.
Ingresso ausiliario
The value of the auxiliary analog input is shown in parameter
IN2.
The function can be:
•
display only (with settable alarms if required);
•
process variable for PID.2;
•
reference for the PID.1 ratio controller if in REMOTE
mode;
•
process variable (PV) setpoint for PID.1 if the controller
is in REMOTE mode;
•
POWER setpoint for PID.1 if the controller is in MANUAL
and REMOTE mode;
•
reset power for PID.1
•
valve position
5.4.
4-point input correction
The 4-point input correction lets you correct the read of the
main input and/or of the auxiliary input by setting four values:
X1, X2, Y1 e Y2.
To enable the function, set parameter Lin at 4.POIN (INPUT.1
menu for main input or INPUT.2 for auxiliary input or INPUT.3
for auxiliary input 2).
The limitations are:
•
X2 must always be larger than X1;
•
X2-X1 must be 10% larger than the full scale of the
selected sensor.
The setting is limited within the defined scale LO.SCL...
HI.SCL (INPUT.1 menu for main input or INPUT.2 for auxiliary
input or INPUT.3 for auxiliary input 2).
"WARNING: The offset function (OF.SCL parameter) and
linearisation itself remain enabled while setting parameters
X1, X2, Y1, Y2. It is best to reset the OF.SCL parameter and
disable 4-point linearisation when editing these 4 parameters,
and then re-enable offset and 4-point linearisation when you
have finished setting them (so that the PV appearing on the
instrument during identification and setting of the 4 points
is the effective one, not the one modified by linearisation)."
When using this function on linear scales (60mV, 1V, 5V, 10 V,
20 mA), you may invert the scale.
The four values may be set in the LIN.4.P menu, as indicated
by the Md.4P parameter:
• RD.ADJ: the user manually selects the parameters in order,
X1, Y1, X2, and Y2, and edits the value appearing on the
display
• CALIB: for values X1 and X2, no value is shown that can
be increased or decreased, but the input is directly shown
(which can be modified with a calibrator)
If you set the second option (Md.4P="CALIB") and press F,
1) The calibrator reading will appear. Now press F
1.1) the calibrator reading will be assigned to the first of
the four parameters X1 (=value of the abscissa of the
first linearisation point)
1.2) display the second parameter X2 (=value of the
ordinate of the first linearisation point)
2) When the second parameter Y2 (=value of the ordinate of
the first linearisation point) appears on the screen, use the
80209C_MHW_850-1650-1850_01-2020_ENG_pag. 197
The scale limit values of the input are settable on the config-
uration menu with parameters LO.SCL and HI.SCL (INPUT.2
menu).
The parameter IN2 is shown in read-only on the user con-
figuration menu.
UP\DOWN buttons to determine the value to be assigned
to this parameter. Once you have set the value, press F to
assign a value to the second parameter Y2 (=value of the
ordinate of the first linearisation point) and then go on to
the next parameter
3) Enter the new parameter and display the calibrator
reading. Now press F
3.1) to assign the calibrator reading to the third of the four
parameters X2 (=value of the abscissa of the second
linearisation point)
3.2) it will pass (go on to) display the fourth parameter
Y2(=value of the ordinate of the second linearisation
point)
4) when the fourth parameter Y2 (=value of the ordinate
of the second linearisation point) appears, use the UP\
DOWN buttons to determine the value to be assigned to
this parameter. Once you have set the value, press F to
assign a value to the fourth parameter Y2 (=value of the
ordinate of the second linearisation point) and then exit
the menu
In both modes, the effective input will appear on the
instrument's display, net of the OFFSET parameter and of
correction of the 4 points (in the LIN.4.P menu, you need not
disable 4-point linearisation or reset the OF.SCLx parameter,
if it has been entered).
Example of typical use
A customer's weights and measures division foriodically checks
linearisation, which has been set to represent a straight line
passing through two points (200, 210),(600, 700)
In this case, proceed as follows:
a) Set the calibrator to 200°C
b) Go into the new LIN.4.P menu and set parameter
Md.4P to "CALIB"
c) Read the Inx parameter at 200°C and confirm the first
parameter by pressing "F"
d) In the second parameter, set 210°C and press "F"
e) Set the calibrator to 600°C
f) Press "F" to confirm the reading of 600°C on the INx
parameter shown
g) Set the fourth parameter to 700°C and press "F"
h) Exit the menu, and the PV will appear with 4-point
correction set
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