Specifications

3.3.3 LEVL 1 (Level 1)

Level 1 is the programming level. The Proportional, Integral, and Derivative

controls are adjusted here. The combination of PID values is virtually limitless.

This allows the controller to be used in a wide variety of applications. However,

this flexibility can also lead to confusion when programming the controller in the

Model 518’s limited mode of operation.

To avoid confusion, this section will discuss which parameters may be adjusted,

which parameters should not be adjusted.

All Parameters are programmed at the ETS Factory to match the Operating

Systems shipped with the Chamber. The programmed values will control the

Chamber within specifications. For better control, the user may adjust the

values. The values listed here are for standard chambers only. Non-standard

units may have different values than those listed here.

The following settings are approximations that will allow any user to achieve

good RH control at any set point (approximately ±2.0 %, depending on the

specific conditions). However, as the user becomes familiar with each parameter

and it’s effect on RH control, the user will be able to program the unit to control

within ever tightening tolerances. Control of ± 0.2% RH, or better, is achievable

with this system.

tunE – (oFF) The Autotune function may be used to help determine the optimum

operating conditions for a given set of operating systems and chamber volume.

The Autotune operates using the Humidifier only. The Dehumidification System

will be disabled during an auto tune. The ‘Tune At Set Point’ (At.SP) option is

recommended with the Model 518.

Occasionally, the message ‘Tune Fail’ will appear in the microprocessor display

after the unit attempts an autotune. The user will need to clear the ‘Tune Fail’

message and attempt another autotune. To clear the message, turn the Model

518 Main Power Switch ‘Off’ and then ‘On’ again. When power is re-applied, the

message will no longer be displayed.

A ‘Tune Fail’ may be caused by many variables. However, performing multiple

‘Tune’ attempts will generally result in a successful ‘Tune’.

bAnd – (10.0) Proportional Band for humidifier.

int.t – (0.5) Integral Time in minutes.

The integral time is responsible for calculating how much output should be

coming from the humidifying and dehumidifying systems to maintain the desired

conditions.