Connecting S7-300 to Lenze Ethernet/IP Drives Protocol Conversion

Overview: The Siemens / Lenze Ethernet/IP Mismatch

A common integration problem on packaging, material handling, and converting lines is the request to attach Lenze drives speaking EtherNet/IP to a Siemens S7-300 CPU 315-2 PN/DP (6ES7315-2EH14-0AB0 and earlier -0AB0x variants). The PLC only has a native PROFINET interface and an MPI/PROFIBUS-DP interface; it has no EtherNet/IP scanner, no CIP stack, and no ODVA-certified assembly class driver.

This reference covers three field-proven integration paths:

1. Migrate the Lenze drives to PROFINET (native Siemens, lowest latency, fewest components).
2. Use PROFIBUS-DP on both the CPU and the Lenze drives (cheapest for large drive counts).
3. Keep the Lenze EtherNet/IP drives in place and bridge them with a third-party protocol gateway (for example the Prosoft Technology PLX31-EIP-SIE).

Protocol Mismatch: EtherNet/IP vs PROFINET vs PROFIBUS

Because the two IP-based protocols are not interoperable, you must either (a) move one side to a common protocol, or (b) install a converter that maintains both protocol stacks simultaneously.

S7-300 CPU 315-2 PN/DP Interface Architecture

The CPU 315-2 PN/DP (current MLFB 6ES7315-2EH14-0AB0) provides two physical interfaces:

• PROFINET side: 2-port managed switch; topology is line, star, or ring (MRP). A line is the most common drive-integration topology.
• PROFIBUS side: 9.6 kbit/s to 12 Mbit/s selectable. For drive integration 1.5 Mbit/s or 12 Mbit/s is typical; bus terminators must be on, and segment length must obey the table in the SIMATIC S7-300 manual.
• The CPU has no CIP/CIP-Safety stack, so any EtherNet/IP device on a directly connected segment is invisible to the user program.

Lenze Drive Communication Module Options

Lenze's mid-range inverter families (i500 in the i-series line, and the legacy 8400 StateLine / HighLine / TopLine / PLC) all support multiple fieldbus options. The communication module typically plugs into the front slot of the drive; the model code determines which one is shipped from the factory.

You confirm the actual module on a delivered drive by reading the model code printed on the front label, or by reading parameter C00012 in the Lenze EASY Starter / L-force Engineer tool.

Solution Path 1: Migrate the Lenze Drives to PROFINET

Best when the Lenze drives are new, not yet wired, or when the customer will absorb the cost of a hardware change.

1. Order the i500 drives with the PN option (PROFINET), or swap the plug-in communication module on existing 8400 drives from E94AYCEC to E94AYCPM.
2. Install the Lenze GSDML-V2.31-LENZE-i500-PN-xxx.xml GSDML file in STEP 7 V5.5 / TIA Portal V15 or later.
3. In HW Config (STEP 7) or the Device Configuration (TIA), drag the i500 from the catalog into the PROFINET line of the CPU 315-2 PN/DP.
4. Set the device IP address and PROFINET device name. With the i500, the name is assigned from the IO Controller using the "Assign device name" wizard in TIA Portal; the drive's rotary switches are not used for PROFINET addressing.
5. Configure the cyclic I/O slots. The default i500 PROFINET slot map is 4 words of process data (PZD) in each direction: control word (STW), status word (ZSW), main setpoint (HSW), main actual (HIW). You can expand to 8/16 PZD by writing parameter C00015 in the drive.
6. Insert the standard S7 FB/SFB "DPRD\_DAT" and "DPWR\_DAT" to move the PZD to/from the I/O image. No vendor-specific FB is required — PROFINET is the same on every drive.

Solution Path 2: PROFIBUS-DP for Lowest Cost per Drive

Best for very large drive counts (the cited example was ~70 drives on one machine) where the cost of a PROFINET module is multiplied by each drive. PROFIBUS modules are typically 30-40% less expensive than PROFINET modules on Lenze drives, and the S7-300 CPU 315-2 PN/DP has the DP master already on-board.

1. Order i500 drives with the PB option (PROFIBUS), or 8400 drives with the E94AYCPM-DP module.
2. Install the Lenze LENZE_0F0C.GSD file in STEP 7 HW Config.
3. Set the PROFIBUS address on each drive using the rotary switches (1-126) on the front of the Lenze communication module. Address 0 is reserved for service tools and must not be assigned to a drive.
4. Configure the DP cycle. For 70 drives at 4 PZD each direction, run PROFIBUS at 1.5 Mbit/s and set the bus cycle to 2 ms. The cable length at 1.5 Mbit/s is limited to 200 m per segment; use a repeater after that.
5. Use the S7 SFC14 / SFC15 ("DPRD\_DAT" / "DPWR\_DAT") to read and write the PZD. The input/output addresses are assigned by HW Config; a typical mapping is PIW 256-263 and PQW 256-263 for the first drive.

Solution Path 3: EtherNet/IP to S7 Protocol Gateway

Best when the customer refuses to change the Lenze drives (cost, lead time, or installed-base constraint) and a protocol translator is acceptable. The product most often used in this exact S7-300 to Lenze EtherNet/IP scenario is the Prosoft Technology PLX31-EIP-SIE.

The gateway sits between the S7-300 and the Lenze drives and makes each side think it is talking to its native protocol. The S7-300 programs against the gateway as if it were another S7 CPU, and the Lenze drives program against the gateway as if it were an Allen-Bradley Logix scanner.

Hardware Topology with the PLX31-EIP-SIE

S7-300 CPU 315-2 PN/DP
   Port 1 (PROFINET) -----> managed Ethernet switch -----> PLX31-EIP-SIE (Siemens side)
                                                                |
                                                       Ethernet/IP (ODVA)
                                                                |
                                                       Managed Ethernet switch
                                                          |      |      |
                                                       Lenze   Lenze   Lenze
                                                       Drive1  Drive2  DriveN

Two physical segments are required: a Siemens Industrial Ethernet segment between the CPU and the gateway, and a separate EtherNet/IP segment between the gateway and the Lenze drives. Keep the two segments on different switches, or use a VLAN-aware managed switch with the ports properly tagged, to keep PROFINET multicast and CIP multicast from contending on the same broadcast domain.

STEP 7 / TIA Portal Configuration for the Gateway Path

1. Set the PLX31-EIP-SIE IP address using Prosoft Configuration Builder; default is 192.168.1.100.
2. In STEP 7 or TIA, place an "Other Station / S7 Connection" partner with the gateway IP and rack/slot = 0 (the gateway emulates an S7-300).
3. Use S7 PUT / GET (SFB14/SFB15) or the "S7-300 Ethernet Communication" FBs supplied with Prosoft to write to the gateway's data buffer at word offset 0, and read from offset 0.
4. Map the data buffer to the Lenze EtherNet/IP assemblies: write the first N words to Lenze output assembly 101 (control word + setpoints); read the first M words from Lenze input assembly 102 (status word + actuals).

Lenze EtherNet/IP Data Mapping

Data Mapping and Cycle Time

Latency through the gateway is the sum of three delays:

1. Siemens side: S7 send cycle. With PUT/GET on a 315-2 PN/DP, the typical S7 send cycle is 50-100 ms; for deterministic behavior configure a 20 ms OB1 cyclic interrupt (OB35) and call PUT/GET only there.
2. Gateway internal scan: the PLX31-EIP-SIE polls the EtherNet/IP side at 10-20 ms per assembly.
3. Lenze side: i500 EtherNet/IP RPI (Requested Packet Interval) is 1-10 ms; assembly 101/102 default RPI is 5 ms.

Total loop time, end-to-end, is approximately 20-100 ms depending on OB cycle and gateway scan settings. This is acceptable for V/Hz-driven pumps, fans, and conveyors. For high-speed torque mode or position control, choose Solution Path 1 (PROFINET IRT) to keep the loop under 4 ms.

Verification and Diagnostics

Troubleshooting Matrix

Field-Commissioning Notes

• When mixing protocols on the same physical Ethernet, always separate them on different switches, or at minimum on different VLANs. PROFINET uses LLDP multicast and CIP uses UDP broadcast, and a single misconfigured managed switch will break both at the same time.
• For an S7-300 driving more than 30 drives, set the S7-300 OB1 cycle to at least 20 ms and use a separate OB35 cyclic interrupt for the drive I/O. Do not poll all drives from OB1 or the cycle time will be starved.
• On Lenze drives, always set parameter C00121 "Bus source for control word" to the fieldbus slot (3 = EtherNet/IP, 4 = PROFINET, 5 = PROFIBUS) before commissioning, otherwise the drive ignores the control word even though the bus communication is healthy.
• Save the Lenze parameter set to the file system (EASY Starter → Save parameters to file) and store a copy in the project archive. This makes the next swap-out a five-minute job instead of a half-day re-tune.

Selection Guide: Which Path to Choose

FAQ