4.1 Mounting ST 3000 Transmitter, Continued

Precautions for Mounting Transmitters with Small Absolute or Differential Pressure Spans, continued

For a transmitter with a small differential pressure span, you must ensure that the transmitter is vertical when mounting it. You do this by leveling the transmitter side-to-side and front-to-back. See Figure 6 for suggestions on how to level the transmitter using a spirit balance. You must also zero the transmitter by following the steps in Table 9 below.

Table 9

Zero Corrects Procedure for STD110

 

 

 

 

 

 

 

 

 

Step

 

 

 

Action

 

 

 

 

 

 

 

 

 

1

Attach the transmitter to the mounting bracket but do not completely

 

 

tighten the mounting bolts

 

 

2

Connect a tube between the input connections in the high pressure

 

 

(HP) and low pressure (LP) heads to eliminate the affects of any

 

 

surrounding air currents.

 

 

3

Connect 24 Vdc power to the transmitter and connect a digital

 

 

voltmeter or SFC to read the transmitter’s output. See Figure 1 for

 

 

typical SFC connection or connect a voltmeter across the 250 ohm

 

 

resistor, if desired.

 

 

4

Use the SFC (or SCT) and establish communications with the

 

 

transmitter. Follow the steps in Table 2, if needed.

 

5

While reading the transmitter’s output on an SFC or a voltmeter,

 

 

position the transmitter so the output reading is at or near zero and

 

 

then completely tighten the mounting bolts.

 

6

Do an input zero correct function using the SFC and following the

 

 

steps below. This corrects the transmitter for any minor error that

 

 

may occur after the mounting bolts are tightened.

 

7

 

 

 

 

 

 

 

 

 

 

^

 

 

 

Initiate shift key selection. Press

SHIFT

key

 

 

 

 

 

 

 

 

 

INPUT

 

 

 

 

 

 

J

 

 

 

 

 

 

 

OUT-

 

 

 

 

 

 

Press

PUT

 

key. Read applied input pressure.

 

 

RESET

 

 

 

 

 

 

 

 

 

COR-K

 

 

 

 

 

 

Press

RECT

key. Prompt asks if the applied input pressure equals

 

 

 

 

 

zero input. If it is zero input, go to next keystroke. If it is not, press

 

 

[CLR] key to exit function and repeat keystrokes.

 

 

 

NON-VOL

 

 

 

 

 

 

ENTER

 

 

 

 

 

 

Press

(Yes)

 

key. Zero input is set equal to applied input pressure.

 

 

 

 

 

 

 

 

 

 

 

 

8

Remove the tube from between the input connections, the power,

 

 

and the digital voltmeter or SFC.

 

 

9

Continue with the remaining installation tasks.

 

 

 

 

 

 

 

 

Continued on next page

28

ST 3000 Release 300 Installation Guide

2/05