First, let's review the advanced figure of the output isolated emitter (Figure 1) that I discussed in the previous post. In this topology, the transmitter is isolated from the power supply and the sensor, and the power supply and sensor share a common ground. Although Figure 1 shows a local power supply, a 4-wire analog input module can power the output isolated transmitter.
Figure 1: Output Isolated 4-Wire Sensor Transmitter with Local Power Supply
Figure 2 is a high-level diagram of a power-isolated transmitter. In a power-isolated transmitter, the sensor and transmitter share a single GND, and the power supply is isolated from them. Therefore, the sensor does not need to be isolated from the transmitter and the current loop, and should be able to safely withstand wiring problems or short-circuit to other potentials on the current loop line.
The circuit in Figure 2 is powered by a source that powers the sensor transmitter locally, similar to the output isolated circuit in Figure 1. Transmitters that accept AC supply voltages will often be used in this configuration. In this configuration, the AC supply voltage must be isolated and converted to a regulated DC voltage to power the sensor and transmitter.
Figure 2: Power Isolated 4-Wire Sensor Transmitter with Local Power
Figure 3 shows a connection diagram for a power-isolated 4-wire transmitter that is powered by the analog input module rather than the local power supply.
Figure 3: Power Isolated 4-wire Sensor Transmitter
You can use the same building blocks I described in the previous blog post to design a power-isolated 4-wire sensor transmitter. Figure 4 shows a simplified circuit example for a power isolated 4-wire sensor transmitter. This transmitter accepts a DC supply voltage; this voltage can be the sensor's local power supply or provided by a 4-wire analog input module. The power-isolated 4-wire transmitter eliminates the need for a method of sending sensor data to the transmitter via an isolation barrier, eliminating the need for a digital or analog data isolation solution.
Figure 4: Power Isolated 4-wire Sensor Transmitter
Natural Gas Generator,Natural Gas Power Generator,Natural Gas Electrical Generator,Power Generator Natural Gas
Jiangsu Vantek Power Machinery Co., Ltd , https://www.vantekpower.com