Multi-Element Temperature Transmitter
7
Installation and Operations Maunual
Section 1 - Introduction and Installation
Using This Manual
This manual describes the operation and usage of the Varec Model 4120 Multi-Element
Temperature Transmitter.
•
Section 1 - Introduction and Installation
•
Section 2 - Operation
•
Section 3 - Specifications and Reference Data
•
Section 4 - MFT/HIU and TankView Support for the METT
•
Section 5 - HART Protocol Implementation
Getting Acquainted
with the Multi-Element
Temperature
Transmitter (METT)
The Varec Model 4120 Multi-Element Temperature Transmitter is designed for use with
two types of tank temperature configurations.
•
Multiple Averaging Temperature Bulb
•
Multiple RTDs
The first configuration uses a multiple averaging element temperature bulb and is
shown in Figure 1. Up to 10 elements are supported. Additionally, it has the capability
to acquire temperature from top and bottom spot elements. The top spot element is
used to measure the temperature of vapor space. In the averaging configuration the top
and bottom probes are expected to be part of the averaging temperature bulb assembly.
All temperature inputs are single wire with two common returns for all elements.
The second configuration uses multiple RTDs and is shown in Figure 2. The RTDs are
mounted at different heights on the side of the tank. Up to 12 RTDs are supported. All
RTDs must be of the 3-wire type and must all be of the same type. That is, they must
all be copper or platinum but not a mix.
The METT converts the resistance values to engineering units and transmits the
information over the HART bus. It is designed for use with the Varec Model 4100
Multifunction Transmitter, Model 4200 Hydrostatic Interface Unit or any other HART
host. The ATTI version is designed to operate with the Varec Model 4000 Advanced
Technology Transmitter.
