Factory calibration, Single point calibration, Two point calibration – Despatch Protocol 3 Controller User Manual
Page 55
Protocol 3 Controller
Owner’s Manual
W
ORKING WITH
O
PERATING
M
ODES
Version 1.2
55
Copyright © 2013 by Despatch Industries.
All rights reserved. No part of the contents of this manual may be reproduced, copied or transmitted in any form or by any
means including graphic, electronic, or mechanical methods or photocopying, recording, or information storage and
retrieval systems without the written permission of Despatch Industries, unless for purchaser's personal use.
5.6.2.3. Factory Calibration
Factory Calibration means there is no calibration offset. Selecting Factory Calibration disables
the Single Point Calibration and Two Point Calibration options. There are no settings to configure
for Factory Calibration.
5.6.2.4. Single Point Calibration
The Single Point Calibration screen shows the current value by which the process input (PV) is
offset. This offset value will be the maintained throughout the controller’s input range. For
example:
1.
The controller displayed an oven temperature of 100 degrees with the
Calibration Offset
set
to
OFF
.
2. But an independent measurement of oven temperature reveal an actual temperature of 110
degrees inside the oven
3. Use
and
to enter a
Calibration Offset
of 10 degrees. This Calibration Offset
increases the displayed temperature by 10 degrees to match the actual temperature measured
in the oven.
4. Press
.
5.6.2.5. Two Point Calibration
Two Point Calibration provides a way to choose two temperature points with two different
offsets. The actual offset at any given temperature will be interpolated between the chosen points
and extrapolated above and below the chosen points. For example:
Given the settings of:
o Calibration Low Temp = 100 °C
o Calibration Low Offset = 1 °C
o Calibration High Temp = 200 °C
o Calibration High Offset = 2 °C
The offset at an oven temperature of 0 °C would be 0 °C, the offset at 150 °C would be 1.5
°C, and the offset at 300 °C would be 3 °C.
To set Two Point Calibration:
1. Use
and
to change the value of
Calibration Low Temp
.
Press
.
2. Use
and
to change the value of
Calibration Low Offset
.
Press
.
3. Use
and
to change the value of
Calibration High Temp.
Press
.
4. Use
and
to change the value of
Calibration High Offset
.
Press
.
Example of Two Point Calibration:
With a controller set to Factory Calibration (no offset)
The display on the control read 100 °C and the actual temperature measured 99 °C.