Custom modbus driver

[oley]

Hi,

I have successfully created a driver that is an extension of DrvModbus. Unfortunately, the generated events do not appear in the web application or in the server log.
I can see them in the device, e.g.

Recent Events
+---------------------+-----+-------------------------------------+
| Timestamp           | Tag | Description                         |
+---------------------+-----+-------------------------------------+
| 18/01/2026 19:18:54 |     | ODWZB. WE 31                        |
+---------------------+-----+-------------------------------------+
| 18/01/2026 19:18:54 |     | POB. WE 18                          |
+---------------------+-----+-------------------------------------+
| 18/01/2026 19:18:54 |     | ZAMKNIĘCIE OPERACYJNE ŁĄCZNIKA 1 
7 |
+---------------------+-----+-------------------------------------+
| 18/01/2026 19:21:45 |     | POB. WE 31                          |
+---------------------+-----+-------------------------------------+
| 18/01/2026 19:21:45 |     | ODWZB. WE 18                        |
+---------------------+-----+-------------------------------------+
| 18/01/2026 19:21:45 |     | OTWARCIE OPERACYJNE ŁĄCZNIKA 1 7   |
+---------------------+-----+-------------------------------------+
| 18/01/2026 19:22:07 |     | ODWZB. WE 31                        |
+---------------------+-----+-------------------------------------+
| 18/01/2026 19:22:07 |     | POB. WE 18                          |
+---------------------+-----+-------------------------------------+
| 18/01/2026 19:22:07 |     | ZAMKNIĘCIE OPERACYJNE ŁĄCZNIKA 1 7 |
+---------------------+-----+-------------------------------------+

The code I use to generate the event is:

DeviceEvent devEvent = new DeviceEvent
{
    Timestamp = eventUtcTime,
    CnlVal = code,
    CnlStat = CnlStatusID.Defined,
    Descr = descr
};

DeviceData.EnqueueEvent(devEvent);

• This topic was modified 2 months, 2 weeks ago by Mikhail.
• This topic was modified 2 months, 2 weeks ago by Mikhail.

[Mikhail]

Hi,
An event generated from the driver should be bound to a device tag.
A device tag should be bound to a channel.
Check this example.

[oley]

Hi Mikhail,

I tried to do this similar to DrvSimulator.

internal static class TagCode
{
    public const string TangoEventCode = nameof(TangoEventCode);
}

public static List<CnlPrototypeGroup> GetGroups()
{
    List<CnlPrototypeGroup> groups = new List<CnlPrototypeGroup>();

    CnlPrototypeGroup group = new CnlPrototypeGroup("Events");
    group.AddCnlPrototype(TagCode.TangoEventCode, "TangoEvent");
    groups.Add(group);

    return groups;
}

DeviceTag eventTag = null;

if (DeviceTags != null)
{
    eventTag = DeviceTags[TagCode.TangoEventCode];
}

DeviceEvent devEvent = eventTag != null
    ? new DeviceEvent(eventTag)
    : new DeviceEvent();

devEvent.Timestamp = eventUtcTime;
devEvent.CnlVal = code;
devEvent.CnlStat = CnlStatusID.Defined;
devEvent.Descr = descr;

DeviceData.EnqueueEvent(devEvent);

I have created a channel in Scada bound to TangoEventCode tag.
Now I become an event in web app, but this contains Defined, <code> not my description of the event.

Do I need to create a channel in Scada? If I use this driver for all my devices I have to gave this tag unique name with device number coded or similar.

I want to see my generated event with the description I created for it.

[Mikhail]

A device tag is not null event if it is not bound to a channel.
You should initialize device tags in the driver logic in the InitDeviceTags method.
According to your first message, you already have device tags. For tests, try DeviceTags[0]

[oley]

My problem now is that now I become evens which looks like defined channel data event:

21/01/2026 07:07:13	PV	TANGO	TangoEventCode	Defined, 311.000		
21/01/2026 07:07:13	PV 	TANGO	TangoEventCode	Defined, 310.000		
21/01/2026 07:07:13	PV 	TANGO	TangoEventCode	Defined, 271.000		
21/01/2026 07:07:13	PV 	TANGO	TangoEventCode	Defined, 270.000		

But I create a proper description for my device event in the driver (event is simple code, but has its meaning).

Recent Events
+---------------------+----------------+-------------------------------------+
| Timestamp           | Tag            | Description                         |
+---------------------+----------------+-------------------------------------+
| 20/01/2026 19:08:04 | TangoEventCode | <strong>ODWZB. WE 31</strong>                        |
+---------------------+----------------+-------------------------------------+
| 20/01/2026 19:08:04 | TangoEventCode | POB. WE 18                          |
+---------------------+----------------+-------------------------------------+
| 20/01/2026 19:08:04 | TangoEventCode | ZAMKNIĘCIE OPERACYJNE ŁĄCZNIKA 1 
7 |
+---------------------+----------------+-------------------------------------+
| 21/01/2026 07:07:13 | TangoEventCode | ODWZB. ZAB. f<2                     |
+---------------------+----------------+-------------------------------------+
| 21/01/2026 07:07:13 | TangoEventCode | POB. ZAB. f<2 
0 -100270580 2       |
+---------------------+----------------+-------------------------------------+
| 21/01/2026 07:07:13 | TangoEventCode | ODWZB. ZAB. f>2                     |
+---------------------+----------------+-------------------------------------+
| 21/01/2026 07:07:13 | TangoEventCode | POB. ZAB. f>2 
0 -8.214282E+11 2    |
+---------------------+----------------+-------------------------------------+

I want to see the description in rapid scada event table, in column description. Is this possible?

[Mikhail]

Play with the TextFormat and Text properties of an event.
Link

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