A coupler connects two PLCs on different networks, for example PROFINET to PROFIBUS, EtherCAT, EtherNet/IP, Modbus TCP, MQTT or CC-Link IE Field. Each PLC sees the other side as I/O data, and each network keeps its own PLC, configuration and diagnostics.
Filter by protocol
Select one or more protocols to show only the products that connect them.
Helmholz couplers
Configured completely in the engineering tool of each PLC with the device description file, without extra software. The data exchange runs without handling blocks.
DP/DP coupler
700-158-0AD02. Couples two PROFIBUS masters with 244 bytes of input and 244 bytes of output data, configured in the S7 software or with a GSD file.
More protocol combinations
For other combinations, the Hilscher devices work as a coupler when they are a slave on both sides, that is without master licence. They are configured with the Hilscher gateway configuration software.
netTAP 151
1722.122. Couples two Real-Time Ethernet networks.
CC-Link IE Field / PROFINET coupler
1724.122/PNS. More than 1400 bytes of cyclic I/O data, according to the CC-Link IE Field / PROFINET Network Coupler specification of CLPA and PI.
netTAP 50 and 100
As a slave on both sides the netTAP couples two PLCs, for example a PROFIBUS DP master and an EtherCAT master. Variants and order numbers on the gateways page.
Before you commission
What we check first on a coupler
- Data size per direction. 244 bytes for DP/PN and DP/DP, 600 bytes for PN/EtherCAT, 1024 bytes for PN/PN, PN/EtherNet/IP and PN/Modbus TCP, more than 1400 bytes for CC-Link IE Field. Count the data before you choose, including reserve for later.
- The same I/O layout on both sides. The outputs of one PLC are the inputs of the other, slot by slot. Configure both projects from one list; for EtherNet/IP, download the EDS that matches the configuration from the coupler’s web page.
- Byte order. EtherNet/IP sends multi-byte values in the reverse byte order of PROFINET; with Modbus TCP, check the word order of 32-bit values. Swap them in one PLC, not in both.
- Two networks, two sets of names. The PN/PN coupler is an IO device in both projects. Each side needs its own device name and IP address, and the two networks stay separate.
FAQ
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Can I connect two PROFINET PLCs?
Yes, with the PN/PN coupler (700-158-3PN02). It is a PROFINET IO device on both networks and transfers up to 1024 bytes in up to 16 slots of 1 to 128 bytes. Each side is configured in its own engineering tool with the GSDML file.
How do I couple PROFIBUS and PROFINET?
With the DP/PN coupler (700-158-3DP02): 244 bytes of input and 244 bytes of output data between a PROFIBUS master and a PROFINET controller, configured with the GSD file on the PROFIBUS side and the GSDML file on the PROFINET side. Between two PROFIBUS masters, use the DP/DP coupler (700-158-0AD02).
How do I connect an EtherNet/IP PLC to PROFINET?
With the PN/EtherNet/IP coupler (700-160-3EN02). You configure the data in the Siemens engineering tool and then download the matching EDS file from the coupler’s web page for the EtherNet/IP PLC. Up to 1024 bytes in up to 3 input and 3 output assemblies are available.
How do I connect an EtherCAT master to PROFINET?
With the PN/EtherCAT coupler (700-161-3EC02): up to 600 bytes per direction, with a GSDML file for PROFINET and an ESI file for EtherCAT. Usually you configure only the PROFINET side; common EtherCAT tools read the I/O configuration from the coupler.
How do I connect a Modbus TCP system?
With the PN/Modbus TCP coupler (700-159-3MB02). It is a Modbus TCP server on one side and a PROFINET IO device on the other, with up to 1024 bytes in up to 300 slots. It also offers an MQTT publisher on both network sides.
Can my PLC send data to MQTT?
Yes. The PN/MQTT coupler (700-162-3MQ02) publishes PLC values to an MQTT broker and subscribes to values from it, with the broker on premise or in the cloud. The MQTT settings are made on the coupler’s web page.
Can a netTAP work as a coupler?
Yes. As a slave on both networks a netTAP couples two PLCs, for example the netTAP 151 (1722.122, without master licence) between two Real-Time Ethernet networks. With master licence it becomes a gateway; see the gateways page.
Do I need extra configuration software?
Not for the Helmholz couplers: you configure them in the engineering tool of each PLC with a GSDML, GSD, ESI or EDS file. The netTAP is configured with the Hilscher gateway configuration software, the CC-Link IE Field coupler over mini USB with its own tool.
Selection tool
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Gateways
Field devices under your own PLC
When devices with another protocol have to work under your PLC.
Security
Access between two networks
A coupler passes only I/O data. For remote service across networks, use a NAT gateway with firewall.
Two PLCs to connect?
Tell us which networks and how much data, and we help you choose the coupler.