Instruction Manual

748213-S April 2002

Model 755R

Carefully rotate R63 counterclockwise the minimum amount required to obtain energization of ALARM 1 Relay K1 (See Figure

2-6 below and Figure 3-1, page 3- 3). Energization may be verified by connecting an ohmmeter to relay terminals on 654019 Alarm Relay Assembly.

c.To verify correct adjustment of R63, adjust front panel SPAN Control so that the display or re- corder reads 99% of fullscale. Relay K1 should now be

DE-ENERGIZED.

5.Adjust ALARM 2 control function as follows:

a.With ALARM 2 Setpoint Adjust- ment at 100% (i.e., Position 10 on the dial), adjust front panel SPAN Control so that

A.Typical ALARM 1 Setting

 

 

 

40

 

 

 

 

 

 

INPUT SIGNAL

 

 

 

Percent of Fullscale

DEADBAND SET FOR

30

20% OF FULLSCALE

 

 

 

 

20

B. Typical ALARM 2 Setting

55

 

 

 

INPUT SIGNAL

 

 

 

Percent of Fullscale

DEADBAND SET FOR

50

10% OF FULLSCALE

 

 

 

 

45

 

 

 

 

 

 

b.the display or recorder reads ex- actly fullscale.

c.Set ALARM 2 Calibrate Adjust- ment (R67) to its clockwise limit. Carefully rotate R67 counter- clockwise the minimum amount required to obtain energization of ALARM 2 Relay K2 (See Figure 2-5, page 2-8).

d.To verify correct adjustment of R67, adjust front panel SPAN Control so that the display or re- corder reads 99% of fullscale. Relay K2 should now be

DE-ENERGIZED.

The ALARM 1 and ALARM 2 Setpoint Adjustments are now properly calibrated and may be used to select the desired alarm setpoints, as described in Section 3-6 (page 3-7).

When input signal moves upscale through this point, the coil of ALARM 1 relay (K1) is energized, providing continuity between the common and normally-closed contacts of the relay.

ALARM 1 Setpoint

When input signal moves downscale through this point, the coil of ALARM 1 relay (K1) is de-energized, providing continuity between the common and normally-open contacts of the relay.

When input signal moves upscale through this point, the coil of ALARM 2 relay (K2) is de-energized, providing continuity between the common and normally-open contacts of the relay.

ALARM 2 Setpoint

When input signal moves upscale through this point, the coil of ALARM 2 relay (K2) is energized, providing continuity between the common and normally-closed contacts of the relay.

Figure 2-6. Typical Alarm Settings

2-10

Installation

Rosemount Analytical Inc. A Division of Emerson Process Management