Logix and Omron controller tags over EtherNet/IP right in the chat
Connect EtherNet/IP to the AI agent: tags of Rockwell Logix, Micro800 and Omron NJ/NX controllers through a gateway. The agent shows values and weekly downtime.
How the agent works with EtherNet/IP
Data is read by the gateway: a program installed as a service on a computer or server on the site network that reaches the controller over EtherNet/IP, TCP port 44818. The connection takes the address of the controller or its Ethernet module, the controller kind and the route to the CPU, such as 1,0. The gateway sends data out over outbound connections only.
ControlLogix, CompactLogix and Micro800 list their symbols, so a tag map is optional: the gateway reads the controller and program tags, parses structure templates and reads every value down to elementary types, at most 10,000 tags by default. Neighbouring elements of one array are read in one request, up to 120 elements by default. Before polling the gateway asks the device who it is and names it if the kind does not match.
The protocol is handled by the libplctag library built into the gateway, and only its read functions are declared: the driver has no write to the controller. A tag the controller does not know or will not let the gateway read is marked bad with its code and asked again on the next scan while the others keep reading. A dropped session ends the polling round, and the next one connects anew.
Omron NJ/NX, PLC-5, SLC 500 and MicroLogix do not list their tags, so a tag map is required for them: a variable name or a data table address, such as N7:0, and a type. The gateway sends value changes and repeats a tag that has not changed every 1800 seconds. If the link to the cloud drops, data piles up on the gateway's disk and arrives once it is back.
Integration scenarios
What is in the controller now
The agent finds controller and program tags by name, such as Tank or Program:Main, and shows current values with their timestamp.
Array summary
The agent takes the history of array elements, such as counters Counts[0]…Counts[9], and shows the minimum, maximum, average and last value per hour.
Downtime for the week
The agent takes a week of raw samples of a running status and counts the stops, their length and the total downtime.
A task on a threshold
The agent sets up a task that fires when a tag goes past a threshold and stays there for a set time, not on every sample past it.
Tags that do not read
The agent names tags the controller refused and why: no such tag, the type in the map does not match, an index past the end of an array, reading not allowed.
Gaps in the data
The agent shows history intervals without samples and says whether the site gateway is online right now.
EtherNet/IP examples
14 остановок, в сумме 6 ч 40 мин простоя.
- Самая длинная в среду: 2 ч 05 мин после 14:10
- 9 остановок короче 10 минут, все в первой смене
Считаю по сырым отсчётам тега статуса работы из Program:Main, а не по сводке за час.
How to connect
Before you connect
- A ControlLogix, CompactLogix, Micro800, Omron NJ/NX or PLC-5/SLC controller
- Port 44818 open between the controller and the gateway computer
- A route to the CPU (port and slot) behind an Ethernet module
- For Omron NJ/NX, PLC-5, SLC 500 and MicroLogix: a tag list with types
- A computer on the site network for the gateway service
- Server admits listed addresses only? Allow connections from 158.160.205.91 and 87.228.27.163.
- 1
Find out the controller kind
controllogix also covers CompactLogix; the others are micro800, omron-njnx, plc5, slc500 and micrologix. The gateway checks the kind against the device's answer.
- 2
Write down the route to the CPU
CPU port and slot, comma separated: 1,0 is the backplane, slot 0. A ControlLogix is usually reached through an Ethernet module in its chassis. Micro800 has no route.
- 3
Let port 44818 through to the gateway
EtherNet/IP runs over TCP port 44818. The network between the gateway computer and the controller or its Ethernet module has to let this connection through.
- 4
List the tags for Omron and PCCC
Omron NJ/NX, PLC-5, SLC 500 and MicroLogix do not list their tags. One line per tag: a path, the name or data table address (N7:0) and a type.
FAQ
Add a gateway on the Gateways tab and install it as a service on a computer on the site network. In the connection enter the address, such as tcp://10.0.12.5:44818, the controller kind and the route to the CPU. For Logix and Micro800 the tag map can stay empty; for the others list the tags. Assign the connection to the gateway and it starts polling.
On Logix and Micro800, every user tag of the controller and its programs, including structure members and array elements; system tags of I/O modules are left out. On Omron NJ/NX and PCCC, the tags of the map. For each tag the agent reads the current value, the history in intervals and raw samples.
No. Only the read functions of the protocol library are linked into the gateway; its write functions are not declared there. The agent writes nothing to the controller.
First the controller kind: a Micro800 set as controllogix answers with refusals and timeouts, and the gateway names who actually answered. Then the route to the CPU: port and slot behind the Ethernet module on a ControlLogix, empty on a Micro800. A single tag refused with a code means its name or type in the map does not match the controller.