Installation manual

Series C Controller Configuration and Operation Manual

1-16  Athena Controls, Inc. 900M050U00

1.8 Configuration Sequence Matters

The Athena Series C controllers are versatile instruments that are capable of using many

types of input values and implementing several types of control strategies. To support

this versatility, the Series C controllers are capable of storing values for many

configuration parameters. Interrelationships exist between the parameters. Therefore,

it is important that you configure the parameters in the correct sequence.

If you plan to use a thermocouple or RTD input and if you do not plan to use degrees

Fahrenheit (the default unit of measure), the first step is always to specify the unit to be

used (Celsius or Kelvin) using the dSPLdSPL (display) menu UnitUnit parameter.

The controller

uses this unit of measure for internal operations, as well as for external communications.

When you change the units of measure for temperature inputs, the controller recalculates

any values that have already been specified. For example, if you want the setpoint to be

100 °C, then you must change the units from the default F to C before you write the

setpoint of 100 to the controller. If you change the units after you write the setpoint of

100 to the controller, the controller will convert the 100 °F setpoint to 37.8 °C. In this

case, you would have to reconfigure the setpoint to 100 °C to implement the control

needed by your process.

After the unit of measure has been changed, if necessary, from degrees Fahrenheit to

your choice of Celsius or Kelvin, the next step is always to specify the type of input that

each controller will receive. That means that you must specify the type of thermocouple

or RTD that will provide the input to the controller, or, in the case of a linear input, the

range and units of the input (0 to 20 mA, 0 to 5 V, 1 to 5 V, etc.) The type of input

specified affects how the controller processes the input signal and calculates the output

needed to achieve the setpoint.

With the exception of the unit of measure, generally the parameters should be configured

in the sequence in which they are presented in the menus.

In addition to being aware of the sequence in which parameters should be configured,

you should also remember that not all parameters apply to all applications. For example,

if you specify that the input type is a thermocouple or RTD, then you will not see the low

scale and high scale parameters in the input menu. However, if you use a linear input,

then you must specify scaling values, or accept the factory defaults (-1999 to 9999).

The input type parameter is configured at the factory to match the type of calibration specified when the

controller was ordered (see 5.5.1). If the controller was calibrated and configured at the factory for a

linear input type, the units of measure parameter will not be included in the display menu until you

change the input type. When changing the input from a linear to a temperature input (or vice versa), the

input jumper settings must also be changed as described in 5.3, and the controller must be re-calibrated

as described in Section 18 (unless the “calibrate all” option was specified when the controller was

ordered).

The database values in new (“out of the box”) 1ZC, 16C, 18C, and 25C controllers are always the

default values shown in the tables Sections 5 through 14, except in the case of the input type parameter,

which is configured at the factory to match the type of calibration ordered. (If “calibrate all” was specified,

the input type is set to J thermocouple at the factory.) Instructions for using the controller front panel to

return all database values (including input type) in the 16C, 18C, and 25C controllers to their default

values are in 12.5.