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Figure 40: Simultaneous vs. Multiplexed Architectures
Channel-to-Channel Isolation
Besides differential inputs, floating channels, and a simultaneous architecture, ISO-Channel
technology provides channel-to-channel isolation, not just isolation from the analog front-end
to the computer ground. With this kind of isolation, the channels are individually isolated
from each other and from other system components.
Typically, instrument manufacturers have used relays, isolation amplifiers, or optical isolation
to provide channel-to-channel isolation. These methods have the following advantages and
limitations:
• Relays – This technology provides good galvanic separation and can provide good
accuracy and thermal properties, but relays are slow as they operate on one channel at a
time (10 cycles/s), wear out over time, and are sensitive to magnetic fields. If one relay
sticks, staying closed, the entire system fails!
• Isolation amplifiers – Isolation amplifiers are used in multiplexed architectures. While
they are solid-state, they are expensive, not as accurate, require more power, and generate
more noise and heat than other solutions.
• Optical isolation - Optical isolation is good in digital isolation systems but causes accuracy
problems in analog isolation systems. It is also subject to long-term drift and requires
considerably more power.
With ISO-Channel technology, the A/D is on the sensor side and has its own custom DC/DC
converter. Then, optical or transformer isolation is used to transfer the A/D output data (the
sensor data) digitally. And, due to the simultaneous architecture of ISO-Channel technology,
all data is transferred in parallel.
About ISO-Channel Technology
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