Modbus Relay Optimization: Using Poll on Command, Device Duplication, and Event-

[isabellacog]

Hello everyone,

I am currently monitoring a relay via Modbus, but it has a large number of variables, which makes the polling queue very long and impacts response time.

I have a few questions:

* Is it possible to duplicate the device within the system to separate polling tasks?
For example, one device for continuous reading of essential variables and another only for alert or detailed diagnostic variables.

* I am also considering a logic where, for example, if I receive a critical flag (such as breaker opened), this event could trigger a Poll on Command to request more detailed readings only at that moment. Is this a viable approach?

* Is this strategy generally recommended, or could it create communication conflicts, request collisions, or overload the relay?

* I have never used Poll on Command before. Could someone explain, in general terms, how it works in practice?

* After loading the device and creating the channels, how is the Poll on Command actually triggered?
Does it require manual activation, scripting, event logic, external commands, or is there native automation for this?

My goal is to optimize communication by keeping essential variables updated quickly while performing heavier or more detailed polling only when operational events or alarms occur.

I would appreciate any shared experiences, limitations, or best practices.

[manjey73]

It is possible to duplicate the device. And this is the only way at the moment.
For example, you have a myDevice1 device, you create myDevice1_1 and myDevice1_2 and make different polling patterns, for example, a part for fast polling and a second for slow polling

A team survey requires formulas to work.

[Mikhail]

Hi,

* Is it possible to duplicate the device within the system to separate polling tasks?
For example, one device for continuous reading of essential variables and another only for alert or detailed diagnostic variables.

Yes, this is a good practice.

* I am also considering a logic where, for example, if I receive a critical flag (such as breaker opened), this event could trigger a Poll on Command to request more detailed readings only at that moment. Is this a viable approach?

It is possible to send a polling command with Auto Control Module.

* Is this strategy generally recommended, or could it create communication conflicts, request collisions, or overload the relay?

It looks OK.

* I have never used Poll on Command before. Could someone explain, in general terms, how it works in practice?

Using the Administrator app, try sending a command with the App.Comm.PollDevice code to the selected device.

* After loading the device and creating the channels, how is the Poll on Command actually triggered?
Does it require manual activation, scripting, event logic, external commands, or is there native automation for this?

This checkbox means that an explicit command required to poll a device.

[isabellacog]

I have a question regarding communication lines and device organization.

Currently, I did not follow the best practice of separating devices by communication lines. For example, I am reading data from relays, loggers, and inverters from multiple plants, but I configured all of them in the same communication line. As a result, the polling cycle is taking too long.

I understand that the ideal approach would be to create separate communication lines for different types of devices (for example, one for relays and another for loggers/inverters per plant). However, I already have many devices configured and I would like to avoid losing the existing channel configurations.

My question is:

Would it work if I go to Configuration Database → Primary Tables → Communication Lines and add new communication lines there, even if this changes the order and numbering of the existing ones?

For example, today I have:
1 – UFV Curral Velho
2 – UFV Americano
3 – UFV Flor do Flamboyant

And I would change to something like:
1 – UFV Curral Velho – Relay
2 – UFV Curral Velho – Logger and Inverters
3 – UFV Americano – Relay
4 – UFV Americano – Logger and Inverters
5 – UFV Flor do Flamboyant

After that, I would go to the Devices section and reassign each device to the correct communication line.

Would this approach work safely, or is there a risk of losing configurations, channel mappings, or historical data?

I would appreciate any recommendations or precautions before making this change.

[Mikhail]

You can edit the project as you described. Make a backup before.
The Communicator configuration file ScadaCommConfig.xml should be edited manually (in Notepad++) to move devices to other communication lines. Reopen a project after manual editing.

• This reply was modified 1 month, 4 weeks ago by Mikhail.

[Mikhail]

Historical data is bound to channel numbers. If channel numbers are unchanged, it’s OK.

[Author]

Posts