Model 755A

Instruction Manual

245364-V May 2002

5-7 BUFFER AMPLIFIERS U10 AND ASSOCIATED ANTICIPATION FUNCTION

Refer to Figure 5-9 below. U10 is a noninverting buffer amplifier that incorporates an anticipation arrangement in its input network, thus providing slightly faster response on the readout device(s).

Potentiometer R30 provides a continuously variable adjustment of 5 to 25 seconds for the electronic response time (90% of fullscale) and is factory-set for 20 seconds.

Since the anticipation network attenuates the signal, a gain of 10 is provided by the feedback network associated with U10 to restore the signal to the desired fullscale range of 0 to 10VDC.

The pressure-corrected output signal from

U10 is routed to two output circuits:

•Digital Output Circuit, Section 5-8 on page 5-12

•Analog Output Circuits for Recorder and Alarms, Section 5-9 on page 5-12

 

REF

8052A

 

 

 

Differentiator

 

 

 

 

Network

 

DIGITAL

 

R30

-

 

DISPLAY

 

 

ADC

DISPLAY

 

 

U10

71C03

DRIVER AND

 

 

 

CONTROL

 

 

+

 

 

 

R29

 

 

U18

 

 

 

 

 

 

 

 

5V

+15V

 

 

 

5V REGULATOR

 

 

 

 

 

To Analog Output Circuit

 

 

 

 

(Figure 6-9)

 

 

 

Figure 5-9. Buffer, Anticipation, and Digital Output Circuit

Rosemount Analytical Inc. A Division of Emerson Process Management

Circuit Analysis

5-11