Anderson Manufacturing AV-9000 manual Ax1 Alarm Type, O C E, R I a, E S

11. Press the to advance to the next parameter, ALARM 1 TYPE.

Ax1 ALARM TYPE	Note: Process Values
	must have been defined
	previously in order for
OFF	ALARM prompts to
	appear.

P R O C E

Selections for recorder only

OFF

PROCESS - HIGH

PROCESS - LOW

RATE - RISING

RATE - FALLING

Additional selections for use

with controller option

BAND - WITHIN

BAND - OUTSIDE

DEVIATION - ABOVE DEVIATION - BELOW CONTROL LOOP OPEN*

Press the to change, then to

desired value, then press the .

S S

V A R I A

*When CONTROL LOOP OPEN is selected for ALARM TYPE and NON PID is selected for CONTROL TYPE (CONTROLLERS section of CONFIGURATION), prompt LOOP ALARM TYPE will be displayed

The CONTROL LOOP ALARM is a special alarm which detects faults in the control feedback loop by continuously monitoring process variable response to the control output(s).

The Loop Alarm facility repeatedly checks the control output(s) for saturation. For PID, saturation is either or both outputs being at the maximum or minimum. For On/Off control, saturation is the control output being ON. If an output is found to be in saturation, a timer is started; thereafter, if the saturated output has not caused the process variable to be corrected by a pre-determined amount (V) after a time (Loop Alarm Time) has elapsed, the Loop Alarm goes active. Subsequently, the Loop Alarm facility repeatedly checks the process variable and the control output(s). When the process variable starts to change the value in the correct sense, or when the output comes out of saturation, the Loop Alarm is de-activated.

For PID contron, the internal Loop Alarm Time is always set to twice the inverse of the reset value (Integral Time Constant) parameter. For ON/OFF control, the value of the LOOP ALARM TIME parameter is used..

The value of V is dependant upon the input type:

Temperature:	2oC or 2oF
Linear Ranges:	10 least significant display units

For a single output controller, the saturation condition is simply 0% and OUT 1 MAX %. For dual output control- lers, the saturation condition considers the combination of the two output types, reverse or direct, and responds accordingly.

NOTES: Correct operation of the Loop Alarm depends upon reasonably accurate PID tunings and the Loop Alarm is automatically disabled during manual control. Upon exit from manual control, the Loop Alarm is auto- matically re-enabled (if selected).

B L E S

Section 4	4-37	Edition 3
		Rev G