9.2.3 Current Sensing for Remote I/Os in PLC

In industrial remote IOs, there is often one power supply for several ports, as shown in Figure 45. For example, an IO-Link master has one power supply of 24 V 5 A, but eight IO-Link ports, where each port can deliver up to 1 A. The IO-Link master must measure the total current to make sure in order to not overload the power supply. To prevent from overloading the system, each port is only turned on if sufficient headroom in the total system current is available. Figure 45 shows the block diagram of such a system. This is example is implemented on TI reference design TIDA-010016. The INA253 is an excellent choice for this design because this device is simple to use, and delivers high accuracy over a wide temperature range. The integrated 2-mΩ shunt has a low voltage drop .and therefore low power dissipation.

Figure 45. Current Sensing in Remote I/O