Isolated Signal Converter – Power Distributor Converter (SC-PDC)
Signal Converter – Power Distributor Converter (SC-PDC) is used to supply power all types of transmitter used at the site and to output insulated signal by receiving the signal.
- Size : 75mm(H), 22.5mm(W), 100mm(D).
- Isolation : Input to output to power supply.
- Power supply : AC or DC supply.
- Wiring : Terminal wiring.
- Colour : Gray.
- Weight : About 95g.
- Operating ambient temperature : 0 – 50’C.
- Non operating ambient temperature : – 20’C – 80’C.
- Temperature coefficient : 0.2%/’C.
- Operating ambient humidity : 90% RH max.(non condensing).
- Insulation resistance : <100Mohm with 500VDC.
- Dielectric Strength : 1500VAC @ 1min (input to output to power).
- Adjusment range : 20% (Zero & span) min.
- Conversion accuracy : 15% max.
- Response time : 0 – 90% (0.5sec).
- Input : 4-20mA/DC with DC 24V
- Output: 4-20mA/DC
- Power DC24V / 150mA
Signal isolators provide electrical (galvanic) isolation between the input and output circuits. They couple the signal to the output through a transformer or optical isolator. Signal isolators also break the direct electrical galvanic path between two or more loop points. They protect against dangerous measured-variable voltages and increase protection from surges and spikes.
Signal isolators are closely related to signal converters and signal interfaces. These devices are often used to share, split, boost, protect, step-down, linearize, and digitize process signals.
The most important role of a signal isolator is to break the galvanic path between circuits that are “grounded” to different potentials. A galvanic path is defined as a path in which there is a direct electrical connection between two or more electrical circuits that allow current to flow.
If a differential pressure transmitter is sending a 4-20mA measurement to a receiver, such as a recorder, and the two ground points are different, an additional and unpredictable amount of current can be introduced into the loop, distorting the true measurement. This current path is known as a ground loop and is a very common cause of signal inaccuracies, along with the current path having two grounds, the ground at different potentials, and a galvanic path between the grounds. In order to remove the ground loop, the galvanic path between the grounds must be removed.
Signal isolators are especially important since the other two causes for ground loops cannot always be removed safely. The ground may be there for safe operation of the electronic device.