Omega Engineering CN9400 Calibration to Another Instrument, Heat Cool Strategy Configuration

A d v a n c e d S e t t i n g s

Heat Cool Strategy Configuration (continued)

If no improvement, return to the original value and;

In level 1 halve the value of CYC.2

If the process hunts between heating and cooling, a deadband setting may be needed. Enter a small value, eg. 1 and observe the process. Increase the setting until hunting stops.

Level 1 adjust value SET.2

Water cooled applications

Water cooled applications operating at temperatures greater than 100°C may suffer from the non linear effect caused by water turning to steam. This can be countered by the non linear setting for SP2;

In level 2 set SP2.B to nL in

Multi zone applications

When tuning multi zone applications like extruders, distortions due to thermal interaction between adjacent zones can be minimised by running autotune on all controllers at the same time.

CALIBRATION TO ANOTHER INSTRUMENT

If the controller and instrument readings are different, the ZERO and/or SPAN function in Function Menu Level 3

will require adjustment.

ZERO

Adjust

to make an equal adjustment across the full scale

of the controller andSPAN to make a correction when the error increases/

decreases across the scale.

1 To adjust using the ZERO function

1.1 Substitute measured values in the expression:

Instrument reading – controller reading =			ZERO
Example:
Instrument reading	= 396°
Controller reading	=	400°
396 – 400	=	(-)4°

1.2 Adjust ZERO to (-) 4° to correct error.

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