Omega Engineering CN9400 specifications Overview, O v e r v i e w, Set-Up, Autotune, Installation

INSTALLATION

The Model CN9400 controller is designed to be mounted in a 1/16 DIN panel cut-out. See the INSTALLATION section.

SET-UP

After installation the controller requires programming with the following information:

Type of Input Sensor Operating unit (C or F etc) Type of Output Device Temperature Setpoint

Note: The controller will not be operational until this information is entered.

When the above information has been programmed into the controller it will be operational with the following factory PID (proportional band, integral time, derivative time) settings.

Proportional band/Gain	10°C/18°F
Integral time/Reset	5 mins
Proportional cycle-time	20 secs
Derivative time/Rate	25 secs
DAC Derivative approach control	1.5

OVERVIEW

AUTOTUNE

To precisely control an application the controller will need to be ‘tuned’ using the built-in ‘AUTOTUNE’ feature. Autotune ‘teaches’ the controller the main characteristics of the process and ‘learns’ by cycling the output on and off. The results are measured and used to calculate optimum PID values which are automatically entered in the controller memory.

During AUTOTUNE the optimum cycle-time is calculated but is not automatically implemented. The cycle-time requires manual acceptance unless pre-selected.

To ensure good control over a wide range of applications two versions of the Autotune program are provided, TUNE and TUNE AT SETPOINT.

The TUNE method normally achieves the best results. Starting with the load cool, tuning occurs during warm-up preventing overshoot. This method of tuning is recommended.

The TUNE AT SETPOINT method is used for specialist applications. eg. Heat-cool, multizones and processes below 100°C/200°F. During the tuning cycle some overshoot occurs because the tuning cycle is at set point.

The DAC setting is not re-calculated.

O v e r v i e w

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