Specifications

Addr – (1) Instrument Communication Address. This address may be changed

to any number suitable to the user.

bAud – (9600) The baud rate should be set as high as possible.

dAtA – (18n1) Do Not Change. The data format should not change.

DbuG – (off) Do Not Change. Debugging is an advanced feature that will not be

covered in this manual.

5.3.3 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 controllers in the

Model 518’s limited mode of operation.

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

and 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 tighter control, the user may want to 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 temperature control at any set-point (approximately ±1.0°C, depending on

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

parameter and it’s effect on temperature control, the user will be able to program

the unit to control within ever tightening tolerances. Control of ± 0.2 °C, 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 heater only. The cooling system will be

disabled during an auto tune. The ‘Tune At Setpoint’ (At.SP) option is

recommended with the Model 518 Chamber.

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

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

message will no longer be displayed.