WinCC Flexible: Sending Email to Multiple Recipients

1. Overview

WinCC Flexible (2008 SP5 and earlier runtime suites, superseded by TIA Portal WinCC) exposes a single "Send Email" scripting function that accepts exactly one recipient string per call. Engineers who need notification distribution to operators, supervisors, and on-call rotation lists must therefore wrap the function in a loop, while engineers who need to change the recipient at runtime (e.g., shift handover) must bind an internal string tag to an I/O field. This reference covers both patterns, the alarm-event trigger that is the most common use case, and the tag-change trigger that supports polling or condition-based dispatch.

The technique below works for:

• WinCC Flexible 2008 SP2 / SP3 / SP4 / SP5
• Panels: OP 177B, TP 177B, MP 177, MP 277, MP 377, Comfort Panels (legacy project ported forward)
• PC Runtime: WinCC Flexible RT 2008
• Connection to an SMTP relay (no direct authenticated SMTP in legacy WinCC Flexible)

2. Prerequisites

3. SMTP Relay Configuration

Before any "Send Email" call will succeed, the panel must be able to reach an SMTP server that accepts unauthenticated messages from its IP address. Confirm three things in this order:

1. DNS resolution if you use a hostname. Panels without proper DNS configuration often fail silently. Configure the SMTP server's IP address directly in the script to eliminate this variable.
2. Firewall open TCP/25 from panel IP to relay IP in both directions (some relays respond on high ports for DSN).
3. Relay trust list includes the panel IP. On Postfix: mynetworks = 127.0.0.0/8 192.168.10.0/24 and on IIS SMTP add the panel IP to the relay restrictions whitelist.

4. The Send Email Function

The legacy scripting signature is exposed in VBScript under HMIRuntime:

HMIRuntime.SmartMail "smtp.server.local", 25, "[email protected]", "[email protected]", "Subject", "Body text", False, 0

5. Triggering Email on Alarm Events

WinCC Flexible exposes three event hooks on the Alarm View control. The most useful for notification dispatch is Activate (triggered when the operator opens the alarm screen) or, more reliably, a custom button placed on the alarm screen that calls the script. For purely automatic dispatch, use the Tag Change approach in section 6.

To bind the script to alarm view activation:

1. Open the project in WinCC Flexible ES.
2. Navigate to the screen containing the Alarm View.
3. Right-click the Alarm View, select Properties > Events.
4. Under Activate, click the right column to open the function list.
5. Select Call Script and pick the VBScript you created in section 9.

This fires the script every time the operator brings the alarm screen to the front, which is useful for "email me the current active alarms" workflows.

6. Triggering Email on Tag Value Change

For event-driven dispatch (the most common requirement: "send mail when alarm tag rises"), use the Change Value event on an internal Boolean tag that you set from the alarm bit:

1. Create a new internal tag EmailTrigger of type Bool.
2. In the HMI tag connection, drive it from the PLC's alarm bit using a tag-side script or a direct pointer where the panel is the polling master.
3. Open Tag Properties > Events > Change Value on EmailTrigger.
4. Add a VBScript call that inspects the tag's new value and only sends on the rising edge.

The rising-edge guard prevents flood when the PLC keeps the alarm bit high:

If SmartTags("EmailTrigger") = True Then
  ' rising edge: send
  HMIRuntime.SmartMail "192.168.10.5", 25, "[email protected]", _
    SmartTags("MailTo"), _
    "Alarm: " & SmartTags("AlarmText"), _
    "Tag: " & SmartTags("AlarmTagName") & vbCrLf & _
    "Time: " & Time & "  Date: " & Date, _
    False, 0
  SmartTags("EmailTrigger") = False  ' clear for next edge
End If

7. Sending to Multiple Recipients

The single-recipient signature cannot accept a comma-separated list. Wrap calls in a loop, with the recipient list declared as a VBScript array or parsed from an internal string tag using a delimiter such as ; (semicolons avoid the comma ambiguity in CSV exports).

Dim recipients, i
recipients = Split(SmartTags("MailTo"), ";")
For i = LBound(recipients) To UBound(recipients)
  Dim addr
  addr = Trim(recipients(i))
  If Len(addr) > 0 Then
    HMIRuntime.SmartMail "192.168.10.5", 25, "[email protected]", _
      addr, _
      "Alarm: " & SmartTags("AlarmText"), _
      "Body line 1" & vbCrLf & "Body line 2", _
      False, 0
  End If
Next

Keep the array length bounded; many panels queue SMTP work synchronously and a 20-recipient flood on a busy MP 277 will block the alarm screen for 4-6 seconds. Use 5-8 recipients maximum, or stagger the loop with a counter tag and a cyclical trigger.

8. Dynamic Recipients with an Internal Tag

Bind a WString tag (255 char) to an I/O field on the settings screen. Operators edit the list at runtime; the script reads the tag at trigger time, so the list changes without an ES recompile.

1. Create tag MailTo as WString, length 255.
2. On the Settings screen, drop an I/O field, set Process to MailTo, set Field type to String, untick Hidden input.
3. Document the format in a label: [email protected]; [email protected].
4. Validate the tag on change (optional) to reject addresses without @.

Validation example attached to the Change Value event of MailTo:

Dim s, p
s = SmartTags("MailTo")
p = InStr(s, "@")
If p = 0 Then
  SmartTags("MailToStatus") = "Invalid: missing @"
  SmartTags("MailToValid") = False
Else
  SmartTags("MailToStatus") = "OK"
  SmartTags("MailToValid") = True
End If

9. Complete Script: Alarm-Triggered Multi-Recipient Dispatch

Combine all three patterns. Save as SendAlarmMail.vbs in the project's Scripts folder.

' --- SendAlarmMail.vbs ---
' Trigger: Tag "EmailTrigger" Change Value
' Reads:    MailTo (WString 255), AlarmText (WString 64), AlarmTagName (String 32)
Const SMTP_HOST = "192.168.10.5"
Const SMTP_PORT = 25
Const MAIL_FROM = "[email protected]"

If Not SmartTags("EmailTrigger") Then Exit Sub
If Not SmartTags("MailToValid") Then
  HMIRuntime.Trace "Mail dispatch aborted: recipient list invalid"
  Exit Sub
End If

Dim list, i, addr, subject, body
list = Split(SmartTags("MailTo"), ";")
subject = "PLANT ALARM: " & SmartTags("AlarmText")
body = "Tag: "   & SmartTags("AlarmTagName") & vbCrLf & _
       "Time: " & FormatDateTime(Now, vbShortTime) & vbCrLf & _
       "Date: " & FormatDateTime(Now, vbShortDate) & vbCrLf & _
       "PLC: "  & SmartTags("PlcName")

For i = LBound(list) To UBound(list)
  addr = Trim(list(i))
  If Len(addr) > 0 And InStr(addr, "@") > 0 Then
    On Error Resume Next
    HMIRuntime.SmartMail SMTP_HOST, SMTP_PORT, MAIL_FROM, _
      addr, subject, body, False, 0
    If Err.Number <> 0 Then
      HMIRuntime.Trace "SMTP error to " & addr & ": " & Err.Description
      Err.Clear
    End If
    On Error Goto 0
  End If
Next

SmartTags("EmailTrigger") = False
SmartTags("LastDispatchCount") = SmartTags("LastDispatchCount") + 1

10. Verification Procedure

1. Compile and transfer the project to the panel. WinCC Flexible ES > Project > Compiler > All (no errors).
2. Start Runtime on the panel.
3. Force the alarm tag from the PLC or simulator. The EmailTrigger must transition False → True.
4. Check the relay log: Postfix logs at /var/log/maillog; IIS SMTP drops messages into C:\inetpub\mailroot\Queue if delivery fails.
5. Check the inbox of the test recipient. Subject line and body should match the script's concatenation.
6. Check the panel trace: WinCC Flexible ES > Tools > Trace > Live view, or via ProSave > Diagnostics. HMIRuntime.Trace lines appear with timestamp.

11. Troubleshooting Matrix

12. Migration to TIA Portal / WinCC Unified

WinCC Flexible reached end of life with the 2008 SP5 update. New projects should target TIA Portal V17+ with WinCC Unified or Comfort Panels (which use the modern TIA runtime). The newer runtime offers authenticated SMTP, TLS, and HTML bodies. The pattern maps as follows:

Engineers maintaining legacy fleets can keep the patterns above indefinitely; the SMTP relay + VBScript combination remains the lowest-friction way to add multi-recipient email to a WinCC Flexible system without ES-side upgrades.

13. Field-Commissioning Checklist

• Confirm panel IP is static and documented.
• Confirm SMTP relay is on a UPS-protected power feed.
• Confirm relay has 7-30 days of disk space for the queue.
• Bind the trigger tag to a PLC tag that does not chatter (debounce 500 ms minimum).
• Add a "Test Mail" button on the settings screen that calls the script with a fixed subject and a known good recipient.
• Log every dispatch with HMIRuntime.Trace and mirror to an audit tag readable via ProSave.
• Schedule a quarterly test that forces a known alarm and verifies mail arrival within 60 seconds.