Alarm Setup

The 9220 controller can be configured to use seven different alarms. Each of the alarms consists of an alarm setpoint, alarm source, alarm type, alarm hysteresis, smart alarm, ON delay time, and a 0 SP blocks alarm value. The alarms come from the factory with a default configuration dependent on the application but also can be modified prior to shipment to your

facility or in the field by a supervisor. 

 

Setpoint

This value is the setpoint for the alarm.  Clicking on this value will display an input box from which the user can select a new value.  The range is from –32767 to 32767.

 

Alarm Source

This option will indicate the source of the alarm.  The options are:

PV 1 Value

PV 2 Value

PV 3 Value

Input 1 Value

Input 2 Value

Input 3 Value

Percent Output 1 Value

Percent Output 2 Value

Percent Output 3 Value

 

Note that PV Value represents the numerical value displayed on the touch screen. Input Value represents the raw value recorded by the 9220 controller. This value is then converted to a meaningful number to the User via various calculations.

 

Alarm Type

This value is the type of alarm used.  Options are:

Process High

Process Low

Band, Normally Open

Band, Normally Closed

Deviation, Normally Open

Deviation, Normally Closed

 

Assuming PV1 Value was selected above and the 9220 has a temperature SP of 1500 °F:

 

Process alarms are defined as a set value. For example, the User may not want to allow the front door to open if the furnace is above 150 °F. The alarm is set as a Process High of 150. Disregarding hysteresis (see next point), this alarm will be active when the Loop 1 temperature PV exceeds 150 °F, regardless of temperature SP.

 

Band alarms are defined as a range around a set point. For example, the User may want to alarm when the furnace temperature deviates by more than 50F. The alarm is set as a Band, Normally Open of 50, Disregarding hysteresis (see next point), this alarm will be active while Loop 1 temperature PV is between 1475 °F – 1525 °F.

 

Deviation alarms are defined as a (either) positive or negative value differing from set point. For this example, refer to the Quench Oil example used in the next point.

 

Hysteresis

This value is the Hysteresis value.  The Hysteresis is a set number that works with the alarm to help control a motor or pump longer to reach a set amount to come back into band before it will shut off the motor or pump.

 

Example: Using quench oil as an example, suppose the SP is 200 °F.  The alarm is set as a deviation of +10 °F.   At 210 °F, the alarm is active and the pump will run to cool the oil.  With a hysteresis of 8 °F, the alarm and pump will turn off at 202 °F.   It will turn back on when it is 10 °F above setpoint.  If the setpoint is still 200 °F, then at 210 °F, it will turn on again.

 

Clicking on this value will display an input box from which the user can select a new value.  The range is from -32767 to 32767.

 

Smart Alarm

This value is a display of the Smart Alarm status.  A smart alarm is an alarm that works with a Process Variable (PV), and, when enabled, it will not be armed until the PV is within band of the setpoint. The alarm sounding - if active - will be disabled until within the SP band. When it is in band, the alarm will go active unless on delay time is set.

 

Example:  If the SP is 1700 °F and the band is 10 °F, the alarm will not be active until the PV reaches 1690 °F.  The value can be either disabled or enabled.

 

On Delay Time

This value is the On Delay Time (in seconds) for the alarm to becoming active.  Clicking on this value will display an input box from which the user can select a new value.  The range is from -32767 to 32767.

 

Zero Setpoint Blocks Alarm

This value will allow a 0 setpoint to block an alarm.  The options are either No or Yes. This feature allows alarms to become inactive during idle times (between recipes) of the controller.

 

Inhibit Source

Alarms can be inhibited in order to prevent false or unnecessary alarm notifications. The Inhibit Source option will allow the user to set the source of the inhibit signal. The options are: None, Input 1 – Input 3,

Soak timer inactive (The alarm will not happen if the furnace is in a soak if this option is selected).

 

Disable on Open Input

An alarm can be disabled when an input is open in order to avoid false or unnecessary alarms. This option will allow the user to specify if the alarm is disabled when the input is open.  The options are either no or yes.