Emerson Process Management 3081 pH/ORP Section Installation, Unpacking and Inspection

MODEL 3081 pH/ORP	SECTION 2.0
	INSTALLATION

SECTION 2.0

INSTALLATION

2.1Unpacking and Inspection

2.2Pre-Installation Set Up

2.3Orienting the Display Board

2.4Mechanical Installation

2.5Power Supply/Current Loop

2.1 UNPACKING AND INSPECTION

Inspect the shipping container. If it is damaged, contact the shipper immediately for instructions. Save the box. If there is no apparent damage, remove the transmitter. Be sure all items shown on the packing list are present. If items are miss- ing, immediately notify Rosemount Analytical.

Save the shipping container and packaging. They can be reused if it is later necessary to return the transmitter to the fac- tory.

2.2PRE-INSTALLATION SETUP 2.2.1 Transmitter Default Settings

Two jumpers and a switch may need to be changed from the factory default settings before installing the transmitter. The settings tell the transmitter the type of temperature element in the sensor, whether the reference electrode is high or low impedance, and the location of the preamplifier. The factory default settings are given below.

	default setting
temperature element	Pt 100 RTD
reference impedance	low
preamplifier location	in transmitter

If your sensor or system is different, the transmitter settings must be changed. If you do not know the type of temperature element in the sensor, whether the reference electrode impedance is high or low, or the location of the preamplifier, refer to Sections 2.2.2, 2.2.3, and 2.2.4.

2.2.2 Temperature Element

The Model 3081 pH/ORP transmitter is compatible with sensors having Pt 100, Pt 1000, or 3K Balco RTDs. pH and ORP sensors manufactured by Rosemount Analytical contain either a Pt 100 or a 3K Balco RTD. Sensors from other manufac- turers may have a Pt 1000 RTD. For Rosemount Analytical sensors, the type of temperature element in the sensor is print- ed on the metalized tag attached to the sensor cable. If the label is missing or unreadable, determine the type of RTD by measuring the resistance across the RTD IN and RTD RTN leads. For the majority of sensors manufactured by Rosemount Analytical, the RTD IN lead is red and the RTD RTN lead is white. For the Model 399-33 ORP sensor, the leads are black and white. The Model 328A sensor has no RTD. The Model 320HP system has a readily identifiable separate temperature element. Resistance at room temperature for common RTDs is given in the table.

If the resistance is...	the temperature element is a
about 110 ohms	Pt 100 RTD
about 1100 ohms	Pt 1000 RTD
about 3000 ohms	3K Balco RTD

2.2.3 Reference Electrode Impedance

The standard silver-silver chloride reference electrode used in most industrial and laboratory pH electrodes is low imped- ance. EVERY pH and ORP sensor manufactured by Rosemount Analytical has a low impedance reference. Certain spe- cialized applications require a high impedance reference electrode. The transmitter must be programmed to recognize the high impedance reference.

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