Instruction Manual

245364-V May 2002

Model 755A

A-4

ADJUSTMENT

 

 

A-5

HIGH ALTITUDE VERSION OPTION

 

Circuit adjustment can be made using the built

 

 

in display together along with a Digital

For applications where the instrument is to be

 

voltmeter.

used above 5400 Feet (MSL) an alternate

 

 

transducer option is available from the factory.

1. Select position 2 on the front panel selector

This version consists of a Vaisala model

 

switch. Connect the DVM (+) to TP1, (-) to TP2

PTB100B transducer (900-1100 hPa range),

 

on the INTERFACE Board. Adjust for zero volts

and an interface board with modified values

 

as closely as possible using potentiometer VR1

for resistors R2 and R4. Contact Rosemount

 

(DMM set to the mVDC range) on this same

Customer Service Center if you require this

 

board.

option.

2.Move the DVM to (TP) 14 and ground (TP10). Adjust the AD625 zero offset adjustment for the lowest zero voltage output. Note! All these adjustments are made at ambient pressure and the display on position 2 should now read zero. The noise should be less than ±1 count.

Procedure is complete.

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Appendix A – Vaisala Pressure Transducer

Rosemount Analytical Inc. A Division of Emerson Process Management