Emerson Process Management 3081 pH/ORP instruction manual Temperature Element, Definition

MODEL 3081 pH/ORP	SECTION 10.0
	PROGRAMMING FOR ORP MEASUREMENTS

10.5 TEMPERATURE ELEMENT

10.5.1 Purpose

This section describes how to match the transmitter to the type of temperature element in the ORP sensor.

10.5.2 Definition

TEMPERATURE ELEMENT: ORP sensors use a variety of temperature ele- ments. The Model 3081 ORP transmitter recognizes the following temperature elements and configurations:

a.three and four wire 100 ohm platinum RTDs

b.three and four wire 1000 ohm platinum RTDs

c.3000 ohm Balco RTD

PROGRAM

tEMP

EXIT NEXT ENTER

A 100 ohm platinum RTD has a resistance of 100 ohms at 0°C. A 1000 ohm plat- inum RTD has a resistance of 1000 ohms at 0°C. A 3000 ohm Balco RTD (Balco is an alloy of 70% nickel and 30% iron) has a resistance of 3000 ohms at 25°C. Although only two lead wires are necessary to connect the RTD to the transmit- ter, connecting a third (and sometimes fourth) wire allows the transmitter to cor- rect for the resistance of the lead wires and for changes in wire resistance with temperature.

The Model 3081 transmitter can also be used with a two-wire RTD. Select a three- wire configuration and jumper the RTD return and -RTD sense terminals (termi- nals 3 and 4, respectively).

10.5.2 Procedure

1.Press PROG on the infrared remote controller (IRC).

2.Press NEXT until the tEMP sub-menu appears in the display. Press

ENTER .

PROGRAM

tC 100-3

EXITENTER

3. The screen shows the tC prompt. Press Ï or Ð to scroll to the desired tem- perature element and wiring configuration. Press ENTER to save.

1000-3	3 wire 1000 ohm RTD
1000-4	4 wire 1000 ohm RTD
100-3	3 wire 100 ohm RTD
100-4	4 wire 100 ohm RTD
3000	3000 ohm Balco RTD

NOTE

A jumper on the analog board must also be set to the appropriate RTD type. See Section 2.2, Pre-Installation Set Up.

4. Press EXIT to return to the process display.

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