Emerson Process Management 755R manual 35

Model 755R

Instruction Manual

748213-S April 2002

3-6 SELECTION OF SETPOINTS AND DEAD- BAND ON ALARM OPTION

The ALARM 1 and ALARM 2 setpoint adjustments (see Figure 3-1, page 3-3) are adjustable for any desired value from 1% to 100% of the fullscale analyzer span. The adjustment screws are graduated from 0 to 10.

Required dial settings for both setpoint adjustments may be determined from either Figure 3-2 or the appropriate equation that follows:

•Zero-based operating range

•Required control setting = (desired alarm setpoint)(10)

fullscale span

Figure 3-2 example:

Operating range, 0 to 5% oxygen

Desired ALARM 1 setpoint = 4% oxygen

Turn potentiometer R64 to 8

Desired ALARM 2 setpoint = 3% oxygen

Turn potentiometer R68 to 6

The desired deadband may be selected via the appropriate trimming potentiometer, R73, for ALARM 1 deadband adjustment and R78 for ALARM 2 deadband adjustment. For any setpoint, deadband is adjustable from 1% of fullscale (counterclockwise limit) to 20% of fullscale (clockwise limit). Deadband is essentially symmetrical with respect to setpoint.

3-7 CURRENT OUTPUT BOARD (OPTION)

The Current Output is set at the factor for 4 to 20 mA. If a 0 to 20 mA output is required, readjust both the zero and span potentiometers (R1 and R2) on the Current Output Board.

RANGE			PERCENTAGE OXYGEN READOUT
%							versus
OXYGEN			ALARM SETPOINT DIAL READING
				Percentage Oxygen Readout
	0.0	0.1	0.2	0.3		0.4	0.5	0.6	0.7	0.8	0.9	1.0
0 to 1
	0	1	2	3		4	5	6	7	8	9	10
					Setpoint Dial Reading
				Percentage Oxygen Readout
	0.0	0.1	0.2	0.3		0.4	0.5	0.6	0.7	0.8	0.9	1.0
0 to 2.5
	0	1	2	3		4	5	6	7	8	9	10
					Setpoint Dial Reading
				Percentage Oxygen Readout
0 to 5	0.0	0.5	1.0	1.5		2.0	2.5	3.0	3.5	4.0	4.5	5.0
	0	1	2	3		4	5	6	7	8	9	10
					Setpoint Dial Reading
				Percentage Oxygen Readout
0 to 10	0	1	2	3		4	5	6	7	8	9	10
	0	1	2	3		4	5	6	7	8	9	10
					Setpoint Dial Reading
				Percentage Oxygen Readout
0 to 25	0	2.5	5	7.5		10	12.5	15	17.5	20	22.5	25
	0	1	2	3		4	5	6	7	8	9	10
					Setpoint Dial Reading
				Percentage Oxygen Readout
	0	5	10	15		20	25	30	35	40	45	50
0 to 50
	0	1	2	3		4	5	6	7	8	9	10
					Setpoint Dial Reading
				Percentage Oxygen Readout
0 to 100	0	10	20	30		40	50	60	70	80	90 100
	0	1	2	3		4	5	6	7	8	9	10
					Setpoint Dial Reading

Figure 3-2. Dial Settings for Alarm Setpoint

Adjustments

Rosemount Analytical Inc. A Division of Emerson Process Management Operation 3-7