Glossary – Athena Technologies 16C User Manual

Page 43

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Alarm Delay

- the time delay between the detection of the alarm

condi-

tion and the initiation and indication of the output action.

Alarm Inhibit

- prevents low setpoint alarm activation during cold startup

applications.

Bias

- allows the operator to compensate for any difference between sensor

temperature and the point to be measured. The process display and set-
point will be offset by the value entered in the Bias parameter in the input
menu. Ex: Desired temperature is 150 degrees. Sensor is adjacent to heater
and reads 50 degrees higher than the actual process temperature. Enter
bias of -50. Enter setpoint of 150. Process will display 150 even though
sensor will be measuring 200 degrees.

Blanking

- controls the time the setpoint value display remains on. After the

set time, the setpoint value display turns off. Pressing any button causes the
setpoint value display to reappear for the selected time interval.

Cycle Time

- The period of time in which the controller’s output completes

an on-off cycle (Proportional Output Type only).

Example: Output type = Mechanical relay

Cycle time = 10 seconds

Output power = 50%

Controller output = 5 seconds closed,

5 seconds open

Deadband

- In On/Off temperature control, it is the band above or below

the setpoint where there is no output action. It has the effect of moving the
apparent setpoint.

Derivative

(rate) - Adjusts the controller gain quickly in response to load

changes.

Failsafe State

- designates the percentage of power output that the con-

troller defaults to after it detects a loop break condition and after the loop
break time has elapsed.

Filter

(in Display menu) - changes the filtering speed for the process value

display only. It does not affect control. This parameter is mainly used to
slow down the flickering of the display when the decimal position chosen is
greater than zero.

Filtering

(in Input menu) - sets the time period over which the process

value is averaged.

Highest Reading

- records the highest process value read by the controller.

It may be reset to zero by using the Raise or Lower arrow keys.

Hysteresis

- In On/Off temperature control, hysteresis represents the band

where the output changes state from deactivated to activated. It prevents
chattering around the setpoint and prevents rapid output cycling.

Integral

(automatic reset) - slowly adjusts the position of the Proportional

Band (range of power output) to eliminate offset error.

Loop Break

- a condition where the input is not changing or responding

properly to the output action. This could be caused by a thermocouple or

Glossary

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