Siemens PLC source and sink type - Solutions - Huaqiang Electronic Network

Electronic scale crystal oscillator 3.2*2.5mm 3225 16M (16.000MHZ) 12PF 10PPM 20PPM 30PPM

F380J106MMA original authentic, spot stock brand NICHICON

One-piece inductor

Siemens PLC is the source type connected to the NPN type switch, then replaced with Mitsubishi PLC is the source type connected to the PNP type switch?

A: Siemens PLC can be either a source type (PNP) or a sink type (NPN), depending on the configuration. Let's break it down:

1. Leakage Logic: When current flows into the signal input terminal, the signal turns ON. This is known as leakage logic, and it typically uses an NPN transistor output characteristic.

2. Source Logic: When current flows out from the signal input terminal, the signal turns ON. This is called source logic, and it usually has a PNP transistor output characteristic.

For example, if you use a positive power supply:

- If the signal terminal sends an "ON" signal and the voltage at that point is low (like 0V), it's considered sink logic (NPN). - If the signal terminal sends an "ON" signal and the voltage is high (such as 24V in most PLCs or inverters), it's source logic (PNP).

So, source inputs are active high, meaning current flows out from the input point, while sink inputs are active low, meaning current flows into the input point.

Mitsubishi's FX3U series PLC supports both source and sink configurations, making it flexible for different applications. Understanding the difference between these two types is crucial when connecting sensors or switches to your PLC system.