Introduction to Siemens PN/PN Coupler for Profinet
Profinet is a fieldbus standard developed by Siemens, leveraging Gigabit Ethernet as its foundation to establish a network connecting programmable logic controllers (PLCs) with distributed terminals (IO). Functioning as a local area network, Profinet finds extensive applications in industrial settings.
The PNPN Coupler, short for Profinet-to-Profinet Coupler, serves the purpose of linking two Profinet networks and facilitating data exchange, supporting a maximum data exchange capacity of 1024 bytes. This data exchange occurs through two corresponding buffers, each comprising an Output area and an Input area. The Output area of one Profinet network aligns with the Input area of the other, and vice versa. Configuration tools are essential for the setup of both the sending and receiving areas. The following diagram illustrates the external and internal views of the Siemens PNPN Coupler.
In the above diagram:
Two PN interfaces for Network 1 (X1-P1 and X1-P2);
Two PN interfaces for Network 2 (X2-P1 and X2-P2);
Power Status LED;
24V power supply (PS1 and PS2);
Diagnostic LEDs for Network 1 and Network 2;
Status LED for Network 1;
Status LED for Network 2;
MAC address of the PNPN Coupler in Network 1;
MAC address of the PNPN Coupler in Network 2;
SIMATIC Micro SD card slot;
The PNPN Coupler employs a redundant power supply design, accommodating two independent 24V power sources (PS1 and PS2). However, only one power source is active at any given time, and in the event of a current power source failure, an immediate switch to the alternate power source occurs. The wiring schematic for PS1 and PS2 is illustrated in the diagram below:
In the provided details:
+24 DC PS1;
-24V DC (Ground) PS1;
Loop Output +24V DC PS1;
Loop Output -24V DC (Ground) PS1;
+24 DC PS2;
-24V DC (Ground) PS2;
Loop Output +24V DC PS2;
Loop Output -24V DC (Ground) PS2;
The two networks (X1 and X2) of the PNPN Coupler are electrically isolated, ensuring that identical IP addresses and device names do not lead to conflicts. Each side integrates a 2-port switch supporting network services such as PING, ARP, SNMP, with diagnostic capabilities. The ports support diagnostic interruption and can be disabled if necessary.
On the upper part of the PNPN Coupler, a row of LED indicators is present for diagnosing relevant issues. The meanings of these indicators are as follows:
SF1—Fault in Profinet Network 1 (Red)
SF2—Fault in Profinet Network 2 (Red)
BF1—Bus Fault in Profinet Network 1 (Red)
BF2—Bus Fault in Profinet Network 2 (Red)
MT1—Maintenance required in Profinet Network 1 (Yellow)
MT2—Maintenance required in Profinet Network 2 (Yellow)
ON—24V DC Power Supply On
LINK—Connection Normal (Green)
RX/TX—Data Transmission/Reception (Yellow)
This concludes the introduction to the PNPN Coupler, and subsequent articles will delve into configuration and programming aspects.