West Control Solutions Pro-EC44 - Manual (Page 79)

Pro-EC44 2-Loop Graphical Profile Controller & Recorder
Pro-EC44 Product Manual - 59540-1 October 2013 Page 72
Multi-point Scaling
If an input is connected to a linear input signal (mA, mV or VDC), multi-point scaling can be
enabled. This allows the linearization of a non-linear signal.
– see Input Configuration Sub-
Menu Screens on page 46.
The Scale Input Upper & Lower Limits define the values shown when the input is at its
minimum and maximum values. Up to 15 breakpoints can scale the input vs. displayed value
between these limits. It is advisable to concentrate the break points in the area of the range
with the most non-linearity, or an area of particular importance to the application.
Set the scale limits, and then enter
the 1
st
scaling point (this is a % of the
scaled input span, and the desired
display value to be shown at that input
value. Next set the 2
nd
point and
display value, followed by the 3
rd
etc.
Continue unit all breakpoints are used
or you have reached 100% of the
input span.
A breakpoint set at 100% ends the
sequence
Figure 46. Multi-point Scaling
Base Calibration Adjustment
Calibration of each input type is carried out during manufacture. This can be verified in the
Service and Product Info screens.
Re-calibration of the internal base values is possible, but should only be attempted by
qualified personnel as it overwrites the factory calibration.
For most applications, base re-calibration is not required during the lifetime of the instrument.
WARNING:
BASE CALIBRATION SHOULD ONLY BE PERFORMED IF ERRORS HAVE BEEN
ENCOUNTERED. REFER TO CALIBRATION CHECK BELOW.
CAUTION: Any calibration adjustment must only be performed by
personnel who are technically competent and authorised to do so.
The equipment used must be in a known good state of calibration.
Required Equipment
To verify the accuracy of the instrument or to carry out recalibration, a suitable calibration
signal source is required for each input type as listed below. Accuracy must be better than
±0.05% of reading:
1. DC linear inputs: 0 to 50mV, 0 to 10VDC and 0 to 20mADC.
2. Thermocouple inputs - complete with 0ºC reference facility, appropriate thermocouple
functions and compensating lead wire.
3. RTD inputs: decade resistance box with connections for three-wire input.
New Linearized
Displayed Values
Non-linear signal
Scale Lower Limit
Scaling Points 2, 3 & 4
To Scale Upper Limit
Scaling Point 1