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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.
2.2 PRE-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.
MODEL 3081 pH/ORP SECTION 2.0
INSTALLATION
SECTION 2.0
INSTALLATION
2.1 Unpacking and Inspection
2.2 Pre-Installation Set Up
2.3 Orienting the Display Board
2.4 Mechanical Installation
2.5 Power Supply/Current Loop
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