Temperature Transmitter
Temperature
transmittersare used in industrial manufacturing as a means of
process control because they can provide feedback regarding temperature during
different stages in the manufacturing process. In order to do this, a
temperature transmitter picks up a signal generated by a temperature sensor,
such as a thermocouple, and then uses the signal to calculate heat levels.
Next, the data regarding temperature is converted into a different kind of
signal and transmitted to a corresponding receiving device.
There are several different kinds of temperature transmitters as well as
several types of mounting set-ups. The three general categories for temperature
transmitters include explosion-proof and weather-proof transmitters, DIN rail
or panel mount transmitters, and head mount transmitters. The three general
kinds of mounting set-ups include rail mounting, field mounting, and head
mounting. Some types of transmitters are named after the mounting method,
meaning there is some overlap between the type and mounting method.
Table of Contents
-Weather-Proof and Explosion-Proof Transmitters
-Panel Mount or DIN Rail Mount Transmitters
-Head Mount Transmitters
-Field Mounting Transmitters
Weather-Proof and Explosion-Proof Transmitters
In
applications where a transmitter must withstand the wear and tear associated
with continuous exposure to the elements, a weather- and explosion-proof
transmitter is appropriate. This particular type of transmitter has an external
enclosure, usually made of stainless steel or a designated explosion-proof
material, which is sealed tightly to protect the sensitive internal components.
Inside, the transmitter is divided into two small chambers: one contains the
sensor and the other contains the electronics associated with calculating
temperature and transmitting a new signal. Weather-proof and explosion-proof
transmitters tend to have a high level of accuracy, and can usually be adjusted
and monitored locally, if needed.
Panel Mount or DIN Rail Mount Transmitters
A DIN rail is
used to mount switches, relays, and transmitters. The rail itself is a piece of
metal that is shaped to enable a device (such as a transmitter) to be attached
using a spring clip, which slides into a bend in the metal rail and secures
itself. The metal rail, complete with attached transmitter, can then be
attached to a panel or a wall. The acronym DIN stands forDeutsches
Institut fur Normung, which is the German Institute for
Standardization. DIN rail transmitters, also called panel mount transmitters,
are usually found in diverse applications because they are relatively low-cost
and can operate with an array of different sensors. Because of the DIN rail
configuration, they are also easy to install. They are somewhat less accurate
than weather- and explosion-proof transmitters because of the longer wiring
configuration necessary for securing the transmitter. For temperature transmitters,
rail mounting is the oldest mounting method.
Head Mount Transmitters
Head mount
transmitters incorporate the transmitter into the connection head, or exterior
housing, of a sensor. Because of this design, they are easy to install and
require minimal wiring, as the sensor head simply becomes a sensor head
transmitter.
Field Mounting Transmitters
This particular kind of temperature transmitter comes installed in its own exterior housing, which enables it to be used "in the field” where conditions may call for extra protection, such as in high performance industrial operations. Field mounted transmitters can be located relatively close to the sensor to increase the strength of the signal.