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Connection Parameters Needed for HMI/cMT Products to Communicate with OPC UA Client using EBPro (EasyBuilder Pro)

Introduction

All Maple Systems HMIs programmed with EBPro (EasyBuilder Pro), including every cMT X Series and cMT Series model, are compatible with OPC UA Client. Configure your Controller and HMI/cMT with the following parameters to establish reliable communication.

Supported Series: Weintek OPC UA Server, Unified Automation, Prosys, Kepware

HMI Settings

ParametersRecommendedOptions
PLC typeOPC UA Client
PLC I/FEthernet
Port no.4840
Security policyNoneNone / Basic128Rsa15 / Basic256 / Basic256Sha256
Message security modeNoneNone / Sign / SignAndEncrypt
Re-Build Certificate when HMI Starts
Use sha-256 mode (default sha-1)
Support Uncertain Initial Value
On-line simulatorYes
Multi-HMI connectYes

When using OPC UA Client for the first time, configure time-related settings under System Parameter Settings → Time Sync./DST.

System Parameter Settings window open to the Time Sync./DST tab, showing NTP server options enabled with pool.ntp.org servers configured.

Update Mode

Request Mode

The OPC UA client actively sends a ReadRequest packet to the OPC UA server. After the server receives the packet, it sends a ReadResponse packet back to the client.

Subscription Mode

The server regularly performs tag sampling on the PLC.

  1. If the value or status of the tag changes, the PublishResponse is sent to the client on the next publishing tick.
  2. If the values do not change, an empty PublishResponse is sent to the client to confirm the connection is still established; otherwise a timeout occurs.
EBPro (EasyBuilder Pro) Device Settings and OPC UA Advanced Settings dialogs showing IP address, port, security policy, authentication mode, and Update Mode set to Subscription.

Certificate

HMI Self-Build Certificate

System Parameter Settings OPCUA tab showing the Client section with HMI self-build certificate with rebuild mode selected.

Re-build Mode

Does the certificate exist in the HMI?

  1. Yes — overwrite the certificate and reload it.
  2. No — create a new certificate and load it.

Not Re-build Mode

Does the certificate exist in the HMI?

  1. Yes — load the credentials already stored in the HMI.
  2. No — no certificate is present and communication with the server is not possible.
Device Settings and OPC UA Advanced Settings dialogs with Security policy set to Basic256, Message security mode set to SignAndEncrypt, and Re-build Certificate when HMI Starts checked.

Custom Certificate

Import a custom certificate from the OPCUA tab in System Parameter Settings.

NOTE: If you choose to import a custom certificate, do not enable Re-build Certificate when HMI Starts — enabling that option will overwrite the imported certificate.

System Parameter Settings OPCUA tab with Custom certificate selected, showing Import and Reset buttons for Certificate and Private key fields.

NOTE: The Custom Certificate function can only be downloaded to the HMI and cannot be used for online simulation.

Supported Data Types

Data typeEBPro (EasyBuilder) data formatMemo
Boolbit
Int16-bit BCD, Hex, Binary, Signed16-bit
UInt16-bit BCD, Hex, Binary, Unsigned16-bit
DInt32-bit BCD, Hex, Binary, Signed32-bit
Real32-bit Float32-bit
UDInt32-bit BCD, Hex, Binary, Unsigned32-bit
LInt64-bit Signed64-bit
ULInt64-bit Unsigned64-bit
Double64-bit Float64-bit

NOTE: EBPro V6.03.02 or later supports 64-bit data types (cMT Series only). The address limit range is 48 bits maximum.

Tag Manager

  1. Add OPC UA Client device in EBPro (EasyBuilder Pro)

    In EBPro (EasyBuilder Pro), add OPC UA Client to the device list. Set the IP address and Port no., then click Security, Authentication… to open the OPC UA Advanced Settings.

  2. Discover the OPC UA Server endpoint

    Click the magnifier icon next to the Endpoint url field to open the Discover Server window. The available security parameters for the OPC UA Server are listed. Click Apply to automatically fill the Security group box fields in the OPC UA Advanced Settings window. Complete the remaining settings and click OK.
    OPC UA Advanced Settings with the Discover Server dialog open, listing available security policies including None, Basic256, and Basic256Sha256 with Sign and Sign and Encrypt variants.

  3. Open Tag Manager

    Click Tag Manager. If a Connection failed message appears, verify the communication parameters.
    EasyBuilder Pro System Parameter Settings Device tab showing OPC UA Client in the device list with the Tag Manager button highlighted.

  4. Rebrowse and expand the server node tree

    Right-click Device and select Rebrowse, then expand the node tree to locate the tags to import.
    Tag Manager Addresses pane showing the Device node right-click context menu with Rebrowse option, and the node tree expanded to show Demo sub-nodes.

  5. Drag addresses to the tag list

    Drag the address to be added to the right-side tag area. If the node has child nodes, they will be added as well.
    Device Address Manager showing the node tree on the left with 001_Dynamic selected, and tags being dragged to the right-side Name/Type/Full Name list.

  6. Review import results in the Log pane

    The Log pane displays import results. Unsupported data types are flagged in the log. For UaStatus error codes, refer to https://www.opcti.com/common-error-codes.aspx.
    Device Address Manager showing imported tags in the right pane and a Log section at the bottom with Info and Error messages about connection status and node browse failures.

  7. Save and exit Tag Manager

    After importing addresses, save and exit: File → Save → Exit.
    Tag Manager File menu open with Save and Exit options highlighted.

Connection Diagnostics

The UaStatus Code address can be used to diagnose communication connection problems. If the project was created before this address was available, open Tag Manager to retrieve the tag, then use an ASCII object to read the data.

  • If the connection is successful, the value GOOD is displayed.
  • On failure, the relevant error code is displayed.
Tag Manager showing the Objects folder expanded with a UaStatus Code tag listed in the right pane.
New ASCII object dialog with Device set to OPC UA Client and Tag set to UaStatus Code, configured to read 20 words.

Common Error Codes and Solutions

1. BadCertificateHostNameInvalid

Reason: The client certificate does not match the HMI.

Solution:

  1. Check the Re-build Certificate when HMI Starts option and download the project again.
  2. If importing a client certificate, ensure the client certificate was created to match the HMI name.

2. BadCertificateTimeInvalid

Reason: The server has determined that the client certificate on the HMI has expired or has not yet taken effect.

Solution:

  1. Check the time setting on the HMI.
  2. Confirm whether the time at which the client certificate was generated is correct. If not, check the Re-build Certificate when HMI Starts option and re-download the project. After the download, confirm the client certificate again.
  3. To confirm the client certificate:
    1. Confirm from the OPC UA Server’s Credential Management System UI.
    2. If the OPC UA server is a Weintek HMI, confirm the client certificate from EasyWeb.

3. BadCertificateUriInvalid

Reason: The ApplicationUri in the user-created client certificate is invalid. This is common when importing a custom client certificate.

Solution: Check the Parse ApplicationUri From Client Certificate option and download the project again.

OPC UA Advanced Settings Session section showing the Parse ApplicationUri From Client Certificate checkbox.

4. BadCommunicationError

Reason: Network communication failed.

Solution:

  1. Verify the target IP address and port number settings are correct. Ping the server to confirm reachability.
  2. Confirm the network cable is connected to the HMI, the network indicator is lit, and the HMI network settings are correct.
  3. After verification, re-download the project or restart the HMI to re-establish communication.

5. BadSecurityChecksFailed

Reason: The OPC UA server does not yet trust the client certificate sent by the OPC UA Client.

Solution: Open the server’s certificate management page and trust the corresponding client certificate.

Example 1 — UA Demo Server:

1.1 Open the UA Demo Server management page and locate the corresponding certificate.

    UA Server Administration Certificates tab showing a list of trusted and untrusted client certificates with status, name, validity dates, and organization details.

    1.2 Trust the certificate

    UA Server Administration certificate list with a right-click context menu showing Trust, Reject, Delete, and Open options for an untrusted certificate.

    Example 2 — Weintek OPC UA Server:

    2.1 Open EasyWeb on the OPC UA server HMI. Navigate to Features → OPC UA → Certificates and switch to the Trusted Clients tab.

      Weintek EasyWeb OPC UA Certificates page showing the Trusted Clients tab with an untrusted UaClient certificate listed.

      2.2 Select the untrusted certificate and click Trust.

        Weintek EasyWeb OPC UA Trusted Clients tab with UaClient@tony-PC certificate selected and the Trust button highlighted.

        6. BadCertificateUntrusted

        Reason: The OPC UA Server does not trust the user certificate exchanged by the OPC UA Client.

        Solution:

        6.1 In the server’s certificate management, switch to the Trusted Users tab and trust the user certificate. Example: connecting to the Weintek OPC UA Server.

          Weintek EasyWeb OPC UA Certificates page on the Trusted Users tab showing an untrusted user-1 certificate with the Trust button.

          6.2 Alternatively, import the user certificate into the HMI in advance, then switch to the Trusted Users page and import the certificate.

            Weintek EasyWeb OPC UA Trusted Users tab showing no data and the Import Certificate button.

            7. BadTooManySessions

            Reason: Multiple devices or sessions are simultaneously connected to the server, reaching its session limit.

            Solution:

            1. Close any other OPC UA client software used for testing.
            2. Do not connect the online simulator and the HMI to the server at the same time.

            Wiring Diagram

            The diagram below shows the Ethernet cable wiring.

            Ethernet straight-through cable pinout diagram showing all 8 wire pairs (W/Orange, Orange, W/Green, Blue, W/Blue, Green, W/Brown, Brown) connected pin-to-pin on both ends.