A signal conditioner is a device that converts one type of electronic signal into a another type of signal. Its primary use is
to convert a signal that may be difficult to read by conventional instrumentation into a more easily read format. In performing this
conversion a number of functions may take place. They include:
When a signal is amplified, the overall magnitude of the signal is increased. Converting a 0-10mV signal to a 0 -10V signal is
an example of amplification.
Electrical isolation breaks the galvanic path between the input and output signal. That is, there is no physical wiring between the
input and output. The input is normally tranferred to the output by converting it to an optical or magnetic signal then it is reconstructed on the
output. By breaking the galvanic path between input and output, unwanted signals on the input line are prevented from passing through to the output.
Isolation is required when a measurement must be made on a surface with a voltage potential far above ground.
Isolation is also used to prevent ground loops.
Converting a non-linear input signal to a linear output signal. This is common for thermocouple signals.
Cold Junction Compensation
Used for thermocouples. The thermocouple signal is adjusted for fluctuations in room temperature.
Many sensors require some form of excitation for them to operate. Strain gages and RTDs are two common examples.
Types of Signal Conditioners
DIN Rail Mount
As the name implies, a DIN rail mount signal conditioner mounts on a DIN rail bracket. DIN rail conditioners are very popular
in industrial applications since they provide a rugged mounting format for either a few or a large number of signal conditioners.
Backplane Mount Conditioners
Certain signal conditioners can also be mounted on a common backplane. The backplane style provides the advantage of all output
signals being accessible through a single common connnector. The backplane style signal conditioners are often used with data acquisition
systems since a single cable can connect multiple conditioners to a data acquisiton device.
Digital Signal Conditioners
Digital conditioners are one of the more recent developments in signal conditioners. The output of a digital signal conditioner is converted to
a digital format such as RS232, RS485 or even Ethernet. Digital signals have several advantages over analog signals. They provide a high degree of immunity from electrical
noise, they can also support extended transmission distances and are easily connected to a computer. With an ethernet output, the input signal can be read
across an entire network or even across the internet if so configured.