Description
Product Introduction & Engineering Value
The 1788-EN2PAR is built for process automation installations where a Logix or PlantPAx controller needs access to PROFIBUS PA instrumentation. Process variables, device status, and extended diagnostics can be brought into the Logix environment through the linking device and its associated Add-On Profile (AOP).
The “PAR” architecture is important: this is the redundant EtherNet/IP-to-PROFIBUS PA version. It is not interchangeable with the 1788-CN2PAR, which provides a ControlNet-to-PROFIBUS PA interface. Rockwell currently classifies the 1788-EN2PAR as a discontinued product in its compatibility database.
Technical Specifications
| Specification | 1788-EN2PAR |
|---|---|
| Device type | EtherNet/IP to PROFIBUS PA linking device |
| EtherNet/IP interface | Redundant network connection |
| PROFIBUS PA | Process automation field network |
| Maximum PA field devices | 24 |
| PA trunk output | 500 mA per trunk |
| Power input | 24–32 VDC |
| Current consumption | 260 mA @ 24 VDC, no field devices attached |
| Power dissipation | 12.24 W @ 24 VDC |
| Ethernet cable | CAT5 STP/UTP |
| Isolation voltage | 30 V continuous, basic insulation |
| Enclosure | Open-style |
| Temperature code | T4 |
| Mounting | DIN rail |
| Configuration environment | RSLogix 5000 / Studio 5000 with AOP |
Rockwell’s technical documentation specifies 24–32 VDC input power, 260 mA consumption at 24 VDC with no field devices attached, 12.24 W power dissipation, CAT5 Ethernet wiring, and 30 V continuous isolation between specified network/power domains.
PROFIBUS PA Architecture
The key advantage of the 1788-EN2PAR architecture is that PROFIBUS PA field devices connect directly through the linking device to EtherNet/IP. Rockwell specifically states that an intermediate PROFIBUS DP layer is not required.
The module can expose:
- Process variables from connected PA devices
- Output process variables
- Linking-device diagnostics
- Extended diagnostics from individual PA instruments
- Device configuration information through the Rockwell engineering environment
Rockwell’s PlantPAx documentation describes support for eight input PVs and eight output PVs from as many as 24 PROFIBUS PA field devices, along with device diagnostics.
Field Application & The “Trench” Experience
A refinery maintenance team is upgrading the control hardware around a process unit without replacing several existing PROFIBUS PA transmitters. The PLC architecture is based on ControlLogix and EtherNet/IP, while pressure, flow, and valve instruments remain on the PA segment.
The 1788-EN2PAR provides the bridge. Instead of replacing every field instrument or inserting a separate PROFIBUS DP architecture, the maintenance team connects the existing PA trunk to the linking device and integrates the device into the Logix I/O tree. The commissioning engineer then verifies the Ethernet configuration, PA device discovery, AOP configuration, and process-variable status.
One detail causes trouble during the first attempt: the team uses an engineering environment that does not properly recognize the particular Series C EN2PAR. Rockwell’s release documentation identifies AOP and software-version dependencies, so the engineering workstation must be checked before commissioning.
Specific application scenarios
- Pressure and flow transmitter integration on a PlantPAx process-control system.
- Control valve position and status monitoring using PROFIBUS PA field devices.
- Process analyzer networks where existing PA instruments need to communicate with a Logix controller.
- Brownfield process-system migration from PA instrumentation toward an EtherNet/IP-based ControlLogix architecture.
Transparency SOP: QA & Testing
For New Surplus or Refurbished 1788-EN2PAR inventory, a useful QA sequence should include:
1. Identity verification
Confirm the exact 1788-EN2PAR catalog number and Series designation.
2. Physical inspection
Check the Ethernet ports, PROFIBUS PA terminals, Phoenix power connector, DIN-rail mechanism, display, housing, and labeling.
3. Power-up test
Apply the specified DC supply and verify normal startup indications and display behavior.
4. Ethernet communication test
Connect the unit to a controlled EtherNet/IP test network and verify network communication and device identification.
5. PA communication test
Where a suitable test network is available, connect representative PROFIBUS PA instrumentation and verify field-device communication.
6. Software integration test
Confirm that the module can be recognized using the applicable Rockwell AOP/engineering environment.
Rockwell’s Product Compatibility and Download Center currently lists Series C for the 1788-EN2PAR and firmware 3.001, along with AOP, DTM, EDS, and firmware downloads.
1788-EN2PAR
1788-EN2PAR
The Veteran’s Tech Trap Guide
⚠️ Trap #1 — Assuming every Studio 5000 version will recognize the module.
Rockwell has documented a specific issue involving 1788-EN2PAR Series C and RSLogix 5000 V20.x. Check the applicable AOP and software compatibility before a planned replacement.
⚠️ Trap #2 — Treating the PA trunk like ordinary Ethernet.
PROFIBUS PA has its own physical-layer requirements, power architecture, termination, and segment limitations. The 1788-EN2PAR’s Ethernet side and PA side must be engineered as two different networks.
⚠️ Trap #3 — Forgetting the RPI.
Rockwell’s user manual gives a default 300 ms RPI for the EN2PAR. With many field devices, setting the RPI unnecessarily low can affect the update behavior of Class 1 and Class 2 data.
PRO TIP: When troubleshooting a PA instrument that appears “offline,” divide the problem into three layers: EtherNet/IP communication → EN2PAR diagnostics → individual PROFIBUS PA device/segment. That prevents a field-instrument fault from being mistaken for an Ethernet gateway failure.
Dynamic FAQ
What is the Allen-Bradley 1788-EN2PAR?
It is an EtherNet/IP-to-PROFIBUS PA linking device designed to connect PROFIBUS PA process instruments with Logix-based control systems. Rockwell describes it as a direct link without an intermediate PROFIBUS DP layer.
How many PROFIBUS PA devices can it support?
The 1788-EN2PAR supports up to 24 PROFIBUS PA field devices and provides 500 mA per PA trunk.
Does the 1788-EN2PAR require PROFIBUS DP?
No. The architecture provides a direct PROFIBUS PA-to-EtherNet/IP connection, so an intermediate PROFIBUS DP layer is not required.
What software is required?
The module integrates into the Logix engineering environment through an Add-On Profile (AOP). Rockwell’s release documentation identifies a minimum module/firmware revision of 2.01 and a minimum RSLogix 5000 software revision of V15.00 for the applicable AOP.
What firmware is available for the 1788-EN2PAR?
Rockwell’s Product Compatibility and Download Center currently lists Series C and firmware 3.001, together with AOP, DTM, and EDS resources.
Is the 1788-EN2PAR still manufactured?
Rockwell’s compatibility/download system identifies the 1788-EN2PAR as discontinued. This makes correct identification and tested replacement inventory particularly important for legacy PlantPAx installations.
How do I verify New Surplus authenticity?
Verify the 1788-EN2PAR catalog number, Series, serial/identification label, physical condition, and firmware information. For surplus inventory, a functional test should also verify EtherNet/IP communication and, where possible, communication with a PROFIBUS PA test device.
What warranty applies?
For New Surplus or Refurbished units supplied by an independent distributor, warranty coverage depends on the supplier. Obtain the warranty terms in writing and distinguish them from Rockwell Automation manufacturer warranty coverage.
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