Hume Datahub SDK Recent Changes

SECS/GEM Software Changes

• An application can install a callback that is executed when HSMS linktest messages are received.  See the hsms command documentation. (10/31/23).
• Hume has added python equipment and host libraries for use with the DMH86 SDK distributions.  Documentation has been added to the DMH86 SDK.
  
• The Tcl localtime command was revised to no longer provide unique, increasing time values if the system clock is set backwards.  (9/26/22).
  
• Optional diagnostic messages when sending the HSMS Select.req control message are newly added so that diagnostic output is similar for all HSMS control messages. (6/15/22).
  
• Better error reply messages for invalid message data have been added to the ::dmh::secs_to_TSN command.  Also, during SECS communication, the last conversion error and last partially-converted SECS list are saved by the SECS Server as variables ::dmh::secs_to_TSN_last_err and ::dmh::secs_to_TSN_partial_msg to provide after-the-fact diagnosis of received invalid message data. (10/28/21).
  
• There is a new procedure secs_CLOCK_reset that can be called to deal with the system clock being changed while an app is running.  The app uses an enhancement to the localtime command; a reset subcommand which causes refreshing of cached system time values. (7/13/21).
  
• A fix was made to the startup initialization of custom Conversation receiving items for Tcl applications. (5/20/21).
• Stream 13 dataset transfer logic was improved to workaround the issue of the other party specifying a maximum RECLEN of 0. (5/14/21).
  
• The Tcl hsms command has new subcommands for receiving or sending messages directly to files or from files.  The update supports communicating messages that are too large to handle in memory.  There is newly added Tcl application code for deploying Stream 21 in the gem2/lib/filesend.tcl file which can be used from the Tcl/Tk host and equipment applications, or used by compiled language applications. The Tcl code also provides a worked example of how to deploy custom large message types. (11/9/2020).
  
• Timestamp values in message tracing now use the procedure ::dmh::tracetimestamp which can be replaced by an app. (6/30/20).
  
• Features to query and set RS-232 serial port signals have been added to the secsport command.  These features are not needed by standard SECS-I; they are used for custom requirements. (4/17/20).
  
• Tcl/Tk Linux application users may notice improved font appearances and more font choices due to Tk being compiled with support for X FreeType fonts.  Users with very large displays can limit the width of table display windows by setting an environment variable HUB_MAX_WIDTH to the maximum pixel width desired. (1/2/2020).
  
• Receiving of non-standard HSMS message function values greater than 127 was fixed. (10/2/19).
  
• If errors occur when appending to a SECS trace log file, the console window is raised if available, and error messages are written to stderr. Usually messages to stderr are printed in the console window with color highlighting. (4/17/18).
  
• Customers who build custom versions of the SecsServer.exe program are advised that the file system paths contained within the SecsServer program file have been revised.  New custom versions should be built using the newer Hume provided SecsServer.exe file as the starting point, and care should be taken not to mix older and new version building scripts. (11/21/17).
  
• The logic for periodic "file saving active" messages when logging SECS communication has been revised to fix an issue on Windows with Daylight Savings Time changes. (4/4/18).
  
• The Conversation feature of the Tcl/Tk applications has been updated to guard against overly long messages being displayed by the Validate message dialog. (8/1/16).
  
• The Trace windows and Status windows of the Tcl/Tk SECS apps have been enhanced to simplify copy-and-paste usage of the SECS communication display. (1/20/16).
  
• Environment variables DMH_CONNECT_DEBUG, DMH_CONNECT_WAIT, and DMH_CONNECT_RETRY may be defined and set to override the default timing during startup when a .NET, C++, or Java app connects to the newly started SECS Server background process.  See the .NET SecsPort DebugEvent or the ServerError event documentation for details. (1/6/16).
  
• A startup problem with paths containing white space and use of the SECS Server on Windows was fixed for the C++ equipment and host libraries. (3/6/15).
  
• The HSMS connection management logic was improved to retry and recover certain socket exceptions that formerly resulted in a disconnection.  (12/22/14).
  
• The installation of the Datahub SDK on Linux systems has been revised so that if the system is installed by root no further setting of file or directory permissions is needed to enable persistence for ordinary users. (7/21/14). 
  
• Changes were made to the .NET HumeDMH.dll and to the Tracewin classes to support receiving and sending ASCII data (TSN type A) that embeds null characters. Similar changes have been made to the Java libraries and the VB6 libraries to enable using null characters in ASCII data.  The C++ and Tcl libraries use the modified UTF-8 byte sequence, 0xc0 0x80, to represent null characters which enables their use in ASCII SECS message data. (4/26/14).
  
• The directory used for Stream 13 dataset transfers can be customized by setting the (DatasetXferDir) value in the SECS Server connection array during initialization. (4/23/14).
  
• The Hume Java applications have been updated to use JDK 1.7 features.  Hume also provides older versions that are compiled for JDK 1.6 and 1.5 on the download site. Only the latest versions are receiving new feature additions. (1/9/14).
  
• Diagnostic messages for HSMS socket exceptions and closes have been improved to better indicate which side initiated the close and to more clearly indicate when additional connection attempts are made.  (11/11/13).
  
• The .NET equipment and host libraries were revised to have better GUI performance of the Tracewin class.   There is noticeably better GUI responsiveness when large Stream 13 transfers are being displayed in the Trace window. (8/21/13).
  
• A new feature of being able to receive or send Stream 7 messages direct from files has been added.  This feature makes it possible to work with S7F3 or S7F6 Process Program transfers that are as large as 16 meg without incurring large memory allocations.  To access the new feature, the HSMS connection array value ppbodyFileMode is set to 1.  This feature has been added to the .NET, Java, and C++ libraries as a new configurable property value.  (5/25/13)
  
• A new property, TraceLogMaxWidth, has been added to most of the libraries to provide a means of reducing the size of log files when the large messages are used.  The data of a message body is logged in a single line.  You are able to configure a maximum number of characters per output line.  Lines that are in excess of the maximum are trimmed and a short explanation is appended. (5/7/13).
  
• The .NET documentation now suggests adding the SecsPort (or SecsHost) projects to your application solution instead of only adding References in order to receive better prompting when editing code.  The source code was edited to include more prompting text. (8/16/12).
  
• A default maximum message size for HSMS is now being set at 2,048,000 bytes.  Previously the default behavior was to have no limit; a limit was only imposed if the recv_max connection array element was set.   This change makes the software resilient to buggy software that sends corrupted message length data in the HSMS packet headers without the developer needing to configure a maximum size.  (3/2/12).
  
• The Tcl/Tk Conversations feature has been enhanced with a new HTML Report feature, resizing of editor windows, expanded size limits, execution of pre-send code when validating message data, and improved merging when loading.  There are new files of host Conversation items which are optionally loaded to exercise E39 Object, E40 Process Job, E87 Carrier, E90 Substrate, E94 Control Job, and E116 Performance messages. (8/20/11 and 1/16/12).
  
• TSN notation now accepts decimal integer values with I8 and U8 64 bit integer values and provides decimal integer values for output. (11/27/10).
  

Host Side

• By default HSMS client connection setups use asynchronous calls that perform better when tools are down.  There may be a new issue with Windows 10 closing these connections when the tool hostname cannot be resolved even though the connection gets successfully setup using the IP address.  To workaround the issue, the user can define and set an environment variable HUME_HSMS_ASYNC to 0, which causes the connection setup to be made with synchronous calls and avoids making calls to resolve the hostname associated with the IP address. (5/5/23).
  
• When receiving event reports with >60k of data, new checks are made so that inserting a row into the ei_event_log table does not fail.  Large variable values received in event reports can exceed this limit and still be passed to compiled apps.  Tcl apps can use the procedure ei_var_query to obtain cached variable values.  (11/18/22).
  
• The Tcl/Tk Host Supervisor has new features of being able to sort the Defined Reports by CEID or Event name, similarly the Parameters and Status Variables tables have new features to sort by name or varID by clicking on the desired column header. (10/11/22).
  
• A fix was made to the .NET SecsHost EventReportConfigs() method. (7/9/21).
• Minor changes were made to the .NET SecsHost and gem2/SecsHost.tcl files so that custom applications can use VFEI features that have been available for Tcl applications. (11/4/18).
  
• The .NET, C++, and Java host libraries have new features to set a base working directory for application data files including *.tab files, log files, and process program transfer directories.  A custom application can set the SupervisorDirectory property before starting.  Programs that call the SupervisorStart method, such as the example .NET and Java host applications can be told to use a specific relative or absolute directory by setting an environment variable, HUME_SUPERVISOR_DIR.  The Tcl Host Supervisor uses a different environment variable TCL_SUPERVISOR_DIR for the same purpose so the different apps can be separately configured. (10/21/18).
  
• The Tcl Host Supervisor PROC_STATE_NAMES Conversation item was revised to fix a minor bug with displaying the correct initial process state for equipment that deploys the ProcessStateNames variable. (1/17/18)
  
• The Tcl Host Supervisor has new 300mm Conversation Items that are loadable from the ../gem2/custom directory that provide for defining event reports and enum variable value mappings for the E40, E87, E90, and E94 300mm standards.  The Conversation Items in 300mm_host.cvt can be loaded and the first item, 300mm-1, can be "Sent" as a shortcut to load and "Send" several Conversation Items.  We show "Send" in quotes because the Send action is used to execute the Tcl code in these Items but SECS messages are not always sent.  "Sending" the 300mm-UI item creates a User Interface for exercising 300mm features including working with Ports, Carriers, Process Jobs, and Control Jobs. (12/12/17 and 1/20/18).
• Handling of alarm information during initialization was revised to synchronize the set/clear state using S5F8 reply data.  Also, S5F5R is sent or not sent per the initialization configuration whereas previously there was optimizing logic that would conditionally skip sending the message. (12/8/17).
  
• The Tcl Host Supervisor supports adding a variable EVENT_DESCRIPTION to event reports with the value being set by the host logic using event descriptions known from the equipment variable EventDescriptions or configured.  Also, a new checkbox provides for adding the formatted event reports seen in the Recent Reports list to the SECS trace for enhanced viewing or logging. (11/21/17).
• The ei_event_log table schema has been updated.  The length of the data column was changed to 60000 from 20000 which allows for processing larger event reports in this table.  Received event report data is parsed and individual variable values are saved in the ei_variable table, so the limits of the ei_event_log table only affects certain modes of processing event report data such as the display to the Tcl Host Supervisor UI.  New error catching logic has been added in case the length limit  is exceeded. (12/19/16).
  
• New Conversation items were added to the Tcl/Tk Host Supervisor for interactive use of S1F21R (DVVALS_QUERY) and S1F23R (EVENTS_QUERY).  The latter item can be used to create Report Definitions for the Event DVVAL associations. (12/14/15).
  
• The initialization for Stream 13 usage was revised to fix a problem with initializing multiple connections. (11/26/15).
  
• A minor fix was made to the Tcl Host Supervisor to correct handling of failure replies to S1F21 or S1F23 during initialization. (6/18/15).
  
• The .NET, Java, and Tcl host GUI applications have an added feature of optionally configuring RPTID values for event reports.  This simplifies working with less capable equipment that cannot use CEID values for RPTID values.  It also reduces the effort needed to manually configure sets of similar event reports. (1/24/14).
  
• The Tcl Supervisor application was revised so that the ei_startup table records are interchangeable with .NET and Java, host supervisor applications.  Also, more options have been made configurable from the Tcl connection startup dialog including new message types S1F21 and S1F23. The ei_startup table schema was revised to include new fields so host developers will need to use updated versions of the SecsServer with updated versions of the Datahub SDK. (1/9/14).
  
• The Tcl secs_xact procedure was revised so that re-entrant execution by Tcl applications is possible.  Also, the asynchronous initialization flow was tweaked so that user written custom initialization procedures are executed from the event loop using after instead of from a SECS receiving callback.  (8/8/13).
  
• A fix was made for the error reply of SendSecsMsg (Java or .NET) when communication is disabled (8/20/12).
• A change was made to prevent extra attempts at communication if communication is enabled repeatedly.  The extra attempts also occurred if communication was disabled momentarily and re-enabled.  The extra attempts were only an issue when communication failed. (7/25/12).
  
• New asynchronous initialization logic that does not nest the SECS Server execution stack has been introduced for the benefit of host applications that connect to large numbers of equipment.  (2/28/12) and (12/22/12)  A fix was made in the use of S2F29 on 3/8/12. 
  
• Support for Stream 7 recipe transfer for recipe body data of type U1 was added. (2/8/12)
  
• A new Host C++ class library and demonstration application is available for Windows and Linux. (12/1/11).
• A .NET Visual Basic program is newly available to demonstrate using the SecsHost Component from VB.  The SecsHostEditor class has been moved from the GemHostApp C# project to the SecsHost component so that it can be used from a VB application. (10/26/11).
• The variable discovery logic was tweaked to fix the names of items that are discovered by event reports occurring before the variables are queried and discovered (1/30/12).
  
• The saving logic for uploaded recipes has a new feature to allow sharing uploaded process programs with multiple equipment connections.  If the array element recipes_are_shared is defined and set to 1, the recipe description records are made shareable.  Each interface should be configured to use the same recipe upload directory when the recipes_are_shared property is defined and set to 1, and the equipment connections should execute in the same SECS Server process. (12/14/2010).
  

Equipment Side

• A fix has been made for .NET and other compiled apps which change the communication configuration dynamically without restarting.  There needed to be preservation of array element values set by custom code or by using the PropertySet() method. (9/27/23).
• A new option to enforce strict variable type usage for message types S1F3 and S2F13 can be set by assigning element value stricttypes to 1 in the Tcl SECS connection array.  Setting the option prevents the host from obtaining non-SV values when using S1F3 or obtaining non-ECV values when using S2F13.  Users of compiled language libraries can use the PropertySet method during initialization to configure this option. (8/28/23).
• Built-in support was added for optionally deploying a ControlStatePrevious SV Variable as varID 302.  The Tcl procedure eq_var_add_ControlStatePrevious $spname  can be called during initialization to add the variable.  OEMs that deploy this variable will typically also call eq_ControlStateModeSet described below to configure how the ControlStateOFFLINE event report data is handled. (8/23/23).
  
• An additional built-in data value variable (DVVAL), ECIDChangeValue, was added to communicate operator ECV parameter value changes along with the existing variable ECIDChangeName.  These variable values are set when the OperatorECVChange event is posted. (7/23/23).
  
• Using a connection name that includes hyphen characters no longer causes errors with certain built-in variable values. (6/24/23).
• Built-in logic has been added to save and restore the enabled/disabled settings of alarms.  A compiled app can override the built-in behavior by setting the connection array element AlarmsAreSaved to 0 using the PropertySet method. (4/19/23).
  
• The replies to S1F3 and S1F11 for an empty list input are now sorted in ascending numeric order of varID.  Previously the reply sequence was the text-sorted order of the variable table select query. (3/7/23).
• New options have been added which can be set by assigning element values in the Tcl SECS connection array.  Setting the option wbit_s5f1 to 1 causes S5F1 alarm report messages to be sent with the reply-wanted header bit set.  Setting the option wbit_s6f1 causes S6F1 trace report messages to be sent asking for a reply.  Setting the option spool_no_reply to 1 causes activation of spooling to occur if the host fails to reply to a primary message and spooling is enabled and configured.  Setting all these options to 1 can help to detect a lost host connection sooner and help prevent the loss of messages.  A new method PropertySet has been added to the .NET SecsPort, and C++ SecsEquipCpp for convenient setting of these and similar options. (2/27/23).
  
• Built-in support has been added to respond to introspection message types, S2F51 through S2F63. (12/22/22).
• Spooling logic was improved for large messages.  The previous length limit of 70,000 characters per spooled message has been removed. (9/16/21).
• Hume has addressed a logical flaw in the standards that the ControlStateOFFLINE event report can only be sent when online, but certain customers expect the ControlState variable value to show an offline state.  The OEM can call the eq_ControlStateModeSet procedure during initialization to have reported values be for the intended state and not the actual state.  The procedure is defined in gem2/equip.tcl with calling signature eq_ControlStateModeSet {spname {isLogical 0}}. (9/15/20).
• Improved diagnostic information is provided in error notifications and added to Tracing and logging for errors that occur when formatting event reports. (9/15/20).
  
• Changes are occasionally made to files in the gem2/equip directory for the 300mm SDK, and those changes are not itemized in this document.
  
• Use of the mbx_xact procedure was revised to use a version in the SDK lib directory and the version in gem2/server was removed. (9/7/20).
  
• The EventName DVVAL is now set for S6F15 and S6F17 event report request message types. (5/6/20).
  
• A fix was made so that non-SECS protocol connection attempts to an HSMS server no longer break an existing host connection. (5/6/20).
  
• An error affecting custom Tcl applications not using the default gemsim name was fixed in the Conversation initialization code. (10/14/19).
  
• Field sizes in the ei_trace_active SQL table used to manage Trace Reports (S6F1) have been increased. (6/15/19).
  
• More checks for illegal data resulting in S9F7 error messages have been added to the handling of event report setup messages S2F33, S2F35, and S2F37. (5/29/19).
  
• Edits have been made to support the optional deployment of SEMI E58, the ARAMS standard.  (4/12/19).
  
• Value changes of the control_mode array element are newly passed as StateChange events to support apps where the ControlMode property setting is not set using an operator GUI. (3/9/19).
  
• The logic for handling S2F15 messages that set the value of ECV Parameters has been updated.  If a numeric value type is specified without a size indication (eg., I2 and not I2:1), and the ECMIN and ECMAX values are empty strings, then the host is allowed to set an empty value.  If the host sets a non-empty numeric value, it should be a scalar value (size 1) when there is not a size specified, otherwise the received vector size must match the specified size.  In the usual situation where the host is setting numeric type values, either the ECMIN and ECMAX values may be empty strings in which case the corresponding check against a min or max value is skipped.  However, the passed numeric data value must be within the possible range of the configured value type. (6/9/17).   
  
• The example Tool UI Tcl application has been updated to avoid replacing customized versions of the custom online procedure and the operator spooling alert procedures.  This surfaced as an issue when using Tcl OPC integration.  The startup logic in gemsim was changed so that the Tool UI sets a different value of MODLN, the model name.  (5/9/17).
  
• Methods to send HSMS linktest messages have been added to the C++, .NET, and Java APIs.  The Tcl secs_xact procedure has been enhanced to handle linktests too.  An example use would be to force discovery that the SECS communication is up or down just before an important event report.  Said another way, polling with linktest messages can be used to force discovery of a broken connection, so that spooling is activated sooner or so that the app can synchronize with the link state. (1/27/16).
  
• When the host sets ECV Parameters using S2F15, the t_latest field in the ei_variable table row is now updated to enable notifications whenever the host sets the same variable value.  An interested client can open a subscription to changes in the t_latest field in addition to the usual subscription on variable value updates. (11/4/15).
  
• Additional error trapping was added to the event posting logic in order to provide diagnostic messages for improper variable values. (9/10/15).
  
• The maximum length of an EventName was raised to 256 from 32. (2/23/15).
  
• The property PPFilesByRequest and a file request event have been added to the .NET, Java and C++ libraries.  In March 2015, transfer logic was revised to allow using process program names that are not valid filenames when using the FilesByRequest feature. (11/7/14) and (3/27/15).
  
• DATAID value logic has been revised such that an incrementing value can be sent instead of the CEID value if the application sets the connection array element (dataid) to a starting unsigned integer value. (10/9/14).
  
• The reply logic for S2F23, Trace Initialize Send, has been revised to use newly added TIAACK codes 4 and 5 instead of S9F7. (6/20/14).
  
• New methods have been added to provide a Status Variable, ProcessStateNames, that describes the process states.  This variable is not required by the standards but is recommended by Hume.  The Tcl/Tk Host Supervisor application recognizes this variable and uses it to enhance the display of Process States. (2/27/14).
  
• A new method, serverLicenseCheck, can validate the runtime license when using the SecsServer[.exe] program. (2/25/14).
  
• The logic for adding ECV Parameters has been revised to feature better validation of the method call arguments. (2/21/14).
  
• A new property, SpoolDirectory, has been added to the C++, .NET, and Java libraries to provide explicit control over the file system directory used for persistence.  The updated libraries require updated versions of the SecsServer or Datahub SDK to set the directory value. (1/31/14)
  
• Persistence of the reporting configuration has been revised to save after no changes have been made for one minute instead of only at program exit. (11/11/13).
• HSMS logic has been updated so that applications cannot send SECS data messages unless the connection is in the selected state.  This has surfaced as an issue for host software that is slow to issue the Select.Req control message when the connection is made. (11/11/13).
  
• .NET variable value logic had a flaw that affected the less common situation of using vector variable values with VarValueRequest callbacks and posting events from a non-GUI thread.  The flaw was fixed by revising files in the SECS server; there was no update of the SecsPort component (10/24/13).
  
• Handling of S1F13 was changed so that redundant messages do not cause additional Control State event reports. (4/25/13).
  
• Handling of S2F37 and S6F23 was improved to allow type B values for integers and to reply with S9F7 for more cases of improper values.  S7F1 handling was improved to strictly validate PPID as a valid filename and to perform a maximum length check. (4/18/13)
• Hume has available to SDK purchasers a documentation generation application that creates a customizable SECS/GEM Reference Document from your running equipment interface.  This application is not on the download site.  The application supercedes editing a template document using the output of the ei_html_save procedure. (1/1/13).
  
• The limit on the number of variables in an event report was raised from approximately 200 to over 1000 by revising the ei_report table schema (10/10/12).
  
• A new example application featuring a simple production SECS/GEM UI has been added to the .NET Equipment distribution, the Windows C++ (SecsEquipCpp) distribution, and the Java SecsEquip distribution.  A Start Menu Program item has been added for the Tcl/Tk Tool UI program.  (10/4/12).
  
• New methods varGroupSet and varGroupSetEventPost have been added to the .NET, C++, and Java equipment libraries.  The methods provide higher performance and data integrity for applications which manage SECS variable values in SECS Server variable table.  The Java library was updated to feature group value requests when variable value callbacks are used.  This technique is already present in the .NET and C++ libraries. (9/14/12)
  
• The SECS server logic for replying to S1F4 was revised to improve performance when using more than 600 variables whose values are provided by .NET, C++, or Java equipment applications.  The .NET Equipment application was updated to include an example of using 1000 Status Variables.  (9/13/12).
  
• Methods StartupLoad, StartupRestore, and StartupSave have been added to the VB6 SecsEquip.  A new example tool UI and configuration dialogs have been added to the project, but they have not been integrated into the example application screen flow.  They can be used as a parts kit by the tool developer. (9/1/12)
  
• The Tcl/Tk SECS Server software can show a simple tool operator user interface window that can be used directly by equipment.  To see the UI, run the gemsim program in the gem2/equip directory with "set TOOL 1" as a command line argument.  Right click on the Communication status LED to bring up the Administrator's menu which allows terminating the program. (8/11/12).
• Customization features have been added to the Tcl gemsim application to support direct use for a custom deployment instead of needing to copy and edit it. (8/11/12).
  
• New features have been added to make it easier to deploy an equipment SECS interface using only OPC data items.  (6/14/12).
  
• Length limits for MDLN and SOFTREV data items have been raised to 20 from 6 in accordance with the E5 revision. (3/26/12).
  
• A new Built-in variable, DefaultReportID, and a new feature of providing a default Event Report for every Data Collection Event type that does not have any associated reports have been added.  The Hume Host Supervisor program has a new Conversation Item to utilize this optional feature.  There are brief usage notes in the Equipment Builtins document. (1/19/12).
  
• Built-in support has been added for the S1F21, S1F22, S1F23, and S1F24 discovery message types presented in standard ballot 4824B.  A new method, EventDvvals(), has been added to the .NET, Java, and C++ equipment libraries so that the application can specify the DVVAL variables that are associated with application added data collection events. (11/08/11).
  
• A SECS server procedure, ei_html_save, has been added for the purpose of saving the Alarm, Event, and Variable definitions for a particular equipment interface in an HTML file that is formatted for end users.  The procedure helps with creating SECS reference documentation.  The procedure was enhanced to include DVVALs for each event type and to not require any arguments for the typical deployment of only one equipment interface.   The Tcl Simulator has a new button action on the Variables pane to invoke the procedure.  The .NET SecsPort provides a method HtmlSave to call this procedure. (8/5/11) and (8/15/12).
  
• A new C++ Equipment library, SecsEquipCpp, is now available for Windows and Linux in both 64 bit and 32 bit versions.   The library takes advantage of std::string and STL classes for return types with automatic memory management.  The older VCSecsEquip remains available for Visual Studio 6.  Any C++ developers using Visual Studio 2005 or newer are encouraged to migrate to the superior new version.  See the library documentation and the version difference notes at the end. (4/26/11).
  

OPC Software

• The OPC Supervisor app has newly-added configurable limits when using the Browse or Discover features to enable working with servers that have very large numbers of items. Also, the Browse windows have a new menu action to discovery Items underneath a selected branch of the tree. (10/23/17).
  
• The OPC Supervisor application was updated to disconnect client connections when exit is called so that the application exits cleanly. (5/29/12).
• The OPC client software is being successfully deployed by SECS/GEM equipment OEMs.  New features have been added to directly use OPC data items to manage displaying SECS Server windows including a configuration dialog.  An improvement has been made to handle version 2 discovery finding new items but ending before completion with an error result. (6/29/12).
• The conversion of received data timestamps to the local timezone is now done in a catch in case the data is not valid. (11/5/15).
  

Tcl/Tk Application and API Changes

• The procedure ::dmh::hub_table_SQL was added to the SDK library.  It was formerly part of the Humelib Components package. (9/7/20).
  
• The ::dmh::localtime and ::dmh::mktime commands now support millisecond timestamps with format codes 17 and 18. (6/30/20).
  
• Hume has added a traditional code debugger for Tcl interpreters that can be used on demand to provide stepping, display of local data values, breakpoints, and execution abort.  See the ::dmh::dbDebug page. (4/14/20).
  
• The Hume ::dmh::dmh_dde command which implements the send command on Windows has been updated to support child interpreters. This makes it possible to use the inspect application to debug parent and child interpreters that co-exist in the same Tcl/Tk application. (3/30/20).
• The client disconnect action featured on the DMH status window was revised. (12/28/18).
  
• A fix was made to window placement logic in the Tk procedures dmh_gets and dmh_win_shrink to fix an issue with dual monitors on Windows when the right monitor is defined as the main screen. (2/13/18).
  
• The unzip.exe program included with the Windows  SDK installer was updated to version 6.0 after a report that the older version failed to run during an install on Windows 10. (10/13/17).
  
• The dmh85 (dmh_wish) executables on Unix now accept the command line option -console with different behavior.  This option now provides a console window using Tk which replaces use of the terminal shell.  The Tk console features use of the cursor for command history recall as well as consolidated input and output. Prior to this change, use of the -console option would enable terminal use when there was an input file and terminal use would ordinarily be disabled. This feature was revised in 2017 so that when -notk is specified with -console on POSIX systems, X-Windows is not used; instead the terminal window is enabled for console IO. (9/15/14) and (6/30/2017).
  
• The Hume SDK license check logic has been modified to be case insensive when matching the system hostname to a dmh_license record. (5/14/14).
• The Tcl/Tk SECS/GEM applications were revised to inform the user of possible licensing issues at startup. (3/25/14).
• The Datahub SDK Setup program was revised to retry and trap errors with adding Program Items to the Start Menu.   A failed installation was reported where success was obtained after running the setup program a second time. (11/14/13).
• The Windows regset -announce command was revised to use SendMessageTimeout instead of SendMessage so that it can be used on systems that are running non-responsive applications.  The issue surfaced as the cause of a failed Datahub SDK installation. (11/14/13).
  
• The .NET DmhClient component library, HumeDMH.dll, had a synchronization flaw that caused rare spurious timeouts for local DoXact calls on very fast systems. (5/10/2012).
• The Hume udp command was revised for IPv6 compatibility. (2/1/12).
  
• Linux Datahub SDK distributions now include Desktop menu program items which are optionally installed using the SETUP program.  (12/30/10).
  
• The Tcl/Tk Datahub has a new set/query option, ADD_SEMICOLON, which causes a semicolon to be appended to SQL statements created by subscriptions or when saving table data.  Also, the SQL insert command has been updated so that the list of column names is optional.  These two changes ease interoperability with the persistent database Sqlite3. (9/25/10).
  

Tcl/Tk 8.5 Compatibility Changes

• The current release of the Hume Datahub SDK includes Tcl/Tk applications that are based on Tcl & Tk patch level 8.5.16 as of September, 2014.  Prior to this, the DMH85 SDK was based on patch level 8.5.15 from December 2013.  From a compatibility point of view, Tcl 8.5 differences from Tcl 8.4 are minor and present few problems (more details).
  
• The Tcl 8.5 distribution is not compatible with the open source tbcload package.  The Hume Data Collection Component (DCC) command dc_encode which is used to obscure passwords is now a compiled dmh package command and the DCC no longer requires tbcload.   With this change, the dmh package version has been changed to 1.3 from 1.2.
  
• Since Tcl version 8.4, the Hume dmh package Tcl extension has been revised to use the ::dmh namespace to prevent name conflicts such as occurred with the Tcl 8.4 lset command.  Read more about the new Tcl 8.4 namespace and compatibility issues in the dmh_import document.  The Hume provided Tcl commands dmh_import, dmh_var, and vset were added to the 8.3 (DMH83) distribution and newer Tcl/Tk distributions to support deploying software that is compatible with Tcl 8.3 and newer.
  
• The Datahub SDK Tcl/Tk 8.5 distribution includes updated versions of the optional packages [incr Tcl],  [incr Tk], and Iwidgets.  You need to use the versions that are matched to your version of Tcl/Tk.  Hume provides a modified index file for these packages so that the correct version is chosen when multiple versions are installed.
  

New with Tcl/Tk 8.5

• Faster execution: Tcl 8.5 is 10% faster than 8.4 with reduced memory usage.
• New widgets: Tk 8.5 features new themed widgets including a tabbed notebook, combobox, and a treeview widget that works well for table data too.
• A new dictionary data structure command dict.
• A new syntax operator causing argument expansion {*} see the wiki discussion.
  
• New core commands such as  lassign, lrepeat, and lreverse.
• New subcommands such as clock add, string islist, and string reverse.
  
• Reorganization of channel related commands in the new chan command.
• Arbitrary-precision integers, new math function commands, and revised use of tcl_precision.
• Many, many more improvements: See the 8.5 Changes page on the wiki.tcl.tk site for details.
  

Hume Changes to the 8.5 Tcl/Tk SourceForge Distribution

• Hume has diagnosed and fixed a problem with executing wish -help (Sourceforge bug report 1938580). (4/9/2008)
  
• Hume has fixed a problem in the Tk library tk::EntryAutoScan procedure which affected ordering keystroke entry on Windows, when using entry widgets with modal windows, and having done a mouse drag selection of text in the entry widget, and releasing the mouse button to the left of the entry widget. This bug and fix have been reported using SourceForge. (12/11/01)
• The command memory_stats is added, and compiled by default for Windows.
• The windows console menu has a new item to display errorInfo, and a new item to display the HTML documentation. Bindings are added for Motif style cut-and-paste and Windows style right button paste. These changes are actually done at runtime without changing the core code.  The changes that Hume has made in the past to make the console safe for memory use are no longer needed - the core has similar logic.  However, Hume has revised the console trimming logic for better performance, and has added a "fast mode" which optionally shortens long output lines.
• The Tk C code is patched for Windows so that the send command and winfo interps work using the Hume DDE command.
• The Tcl library is patched so that index files of the name tclindex.txt are used if tclIndex is not found. This enables Tcl to execute from an ISO 9660 CDROM image where tclIndex is not a valid filename.
• The Tk C code is patched to create an option to the winfo command, timelastevent. Executing winfo timelastevent returns a value that changes with each new window event at your display. This value will be unchanged over time when there has been no user interaction with the window interface. An application can poll this value using after, and determine if the user has been inactive.  Users should migrate to the new Tk 8.5 command tk inactive for this purpose - winfo timelastevent will not be patched into the next version.
  
• Hume compiles the Tcl DLL on Windows so that 256 socket connections are possible. The default compilation results in a limit of 64.
• The windows tclWinPipe.c file is patched so that built in shell commands like "type" work without the user specifying cmd.exe /c. Also, windows batch files with the extension .cmd are made executable.   Hume has also revised handling of windows interactive shell commands in the Tcl library init.tcl file to allow mixed case commands.
• Hume converts the Tcl/Tk man pages to HTML, adds new pages, and provides custom indexes.  Hume has revised the encoding man page which had erroneous information regarding Tcl's internal string representation.