CHANGELOG

### 2.1.4 ###
- Optionally pass configuration filename on the command line of chkcnf.tcl
- Option to initialise an SPI tag to a given value for pdsd
- Options to pass alternative config file, log file, and log dir to pdsd
- Bugfix for the 'exact' tagname search in chkcnf.tcl
### 2.1.3 ###
- Install the pds-scope.py Python utility program
- The plcmm program should format tags' mtime as ISO 8601
- Implement per-block pauses via configuration item
- The tem utility program now quits on Ctrl-C.  It also prints out the initial
  state of the tag.  These mods. address issues #20 and #21.
### 2.1.2 ###
- Various bugfixes and enhancements.  In particular the Unit ID as text bug
  (#15), and the block refresh mode hanging bug (#17).
### 2.1.1 ###
- Added a new Python utility - pds-scopy.py.  This is an oscilloscope for
  plotting a tag in realtime.
### 2.1.0 ###
- Modified configure.in to include variables for enabling the PDS network
  stub.  Based on these variables, the PDS control script will start/stop
  the network stub as well as the PDS.
- Python bindings to PDS API
### 2.0.0 ###
- Rolled the new PDS Network Protocol (PDSNP) APIs, the PDSNP network stub,
  and the PDSNP utility client nwtio from the experimental src tree into the
  main src tree after successful testing.  These new APIs will not affect
  existing clients so FE/BE protocol version has not been incremented.  The
  network stub connects via the PDS API to a local PDS as a client.  It then
  presents a network server interface via a listening socket on its well-known
  port (9574), and accepts network client connections via the PDSNP API.  In
  this way, it network-enables the PDS by acting as a proxy server.  The nwtio
  network client program is analogous to tio for the PDS API.
### 1.3.3 ###
- New utility program force_tag_status.  This allows a tag's status to be
  forced to a user-specified value or a user-specified bit to be set or
  cleared.  This is of most use to set a PLC tag's status to a non-PDS status
  value (e.g., the high (16th) bit) which has the effect of putting comms to
  that PLC offline at runtime (rather than stopping the PDS & commenting-out
  the PLC's comms in the config. file!).
- Minor mods. to plcmm.  It now dynamically calcs. the longest tagname of
  all configured tags & sets the tagname field width accordingly.
- Developed a plc.cnf for the regression test program that uses CIP tags.
- Minor mods. to some of the utility programs (increased field size of tagname
  in plcmm & addrmm, tem now uses new API - PDSget_tag_object() to get a
  pointer to its tag).  Also removed crd from the utility programs that are
  built.  Basically all crd's functionality (& more) is available with
  mcrd.
- Modified the configuration structure (& therefore a lot of the PDS code).
  Rather than just a Unit ID to identify a PLC in the rack, you can now
  specify a full routing path (integers separated by a '.').  This was to
  accommodate the CIP driver.
- The CIP driver (unlike the other drivers) doesn't like to connect/disconnect
  for each query (it falls over after roughly every 150 connections).  The
  solution is to connect (TCP/IP) once, register with CIP once & then fire off
  multiple queries on the connection (which is private to the driver).  The
  driver also (attempts) to determine a comms failure & subsequently reconnect
  as necessary.
- New PDS API - PDSget_tag_object().  This function returns a pointer to a
  tag object identified by its tagname.  This is primarily used to get metadata
  about the tag & was developed to support the CIP need to know type info.
- Added type information (via new function codes for read/writing bits, bytes,
  16 bit ints, 32 bit ints, 32 bit floats, 64 bit floats & a new ascii base
  address convention for specifying array types (append [] to ascii address).
  These changes were made to support the CIP driver because you have to know
  a register's type information for writing to it.
- New code branch to incorporate the new EtherNet/IP (ControlNet - CIP) driver
  into the PDS.
### 1.3.2 ###
- Added a status option to the PDS control script (pds) which reports if the
  PDS is running or not (ala the LSB).
- Replaced various bits of code in the server where it had to check the comms
  protocol before reporting errors so as to address the PLC correctly (either
  IP address:port:unit or tty_dev:unit).  The code now calls the
  PDS_GET_PLC_FQID() macro which stores the PLC's fully-qualified ID in a
  user supplied string.  There is also a PDS_GET_TAG_FQID() macro for getting
  a tag's fully-qualified ID (PLC_FQID tagname).
- A number of small (largely cosmetic) mods. to various PDS utility programs
  to give an overall uniform look/feel.
- New code branch to address the fact that running a status query before each
  data query shouldn't be implicit.  In 1.3.1 (& earlier) every data query was
  preceeded by a status query (to check the run status of the PLC), this was
  implicit in the code & the user had no choice over it.  However, the
  Schneider Premiums (communicated to via the MB driver) do not support Hex
  Function Code 0x11 (Report Slave ID) which the MB driver used to ascertain
  the run status of the PLC (984s, Quantums).  It was thus decided to have a
  command line switch (-s) for the user to decide whether to run a status query
  or not.  This switch is incorporated into the PDS's bit-encoded runtime
  parameters variable (runmode).  Also disabling the running of status queries
  (by not passing -s on the command line) results in a performance increase
  because now the PDS only does 1 query (data) instead of 2 (status & data).
### 1.3.1 ###
- Finally got round to making plcmm run in a "CGI mode" to output HTML
  tables.  This can be used as a CGI script in a shell script wrapper, as a
  SSI exec call in an HTML page etc.
- Rolled the new PDS APIs (accessor macros for the pdsconn & pdstag structs as
  well as some new functions for cycling through the PDS's shared memory data
  & status tags from client programs) from the experimental src tree into the
  main src tree after successful testing.  These new APIs will not affect
  existing clients so FE/BE protocol version has not been incremented.  A new
  version of the PLC memory-mapper utility program has been written to take
  advantage of these new APIs.  It is functionally equivalent to the old one.
- Modified configure to build the PDS control script (pds) at configure time.
  The path to the PDS & its data directory is created from the user's configure
  time 'prefix' rather than hard-coded in the script.
- PDS now logs a timestamp of when it is put offline as well as logging a
  timestamp of when it is put back online.  It also logs the PDS version &
  build time in its startup messages.
- New utility programs to list/control the PDS SPI.  spimm will show a
  memory-map of the SPI, pds_ctl allows getting/setting an SPI variable.
  These programs are analogous to plcmm & tio for the PDS API.
- New (minor) version because the PDS SPI (Server Programming Interface) has
  been added.  These mods. won't break any existing clients as such BUT
  because the server has been modified (to use the SPI) the FE/BE protocol has
  been incremented so clients will need to be rebuilt.
### 1.3 ###
- Added PLC comms protocol to configuration file scanner.
- Configuration file scanner source is now part of the server instead of in
  a separate lib.
- ModBus specific code is now situated in a sub-dir of the server called
  drivers (was in a separate lib).  This sub-dir now also contains a
  DataHighway driver module.
- Configuration file now accepts integer or logical ascii addresses.
  Generally ModBus uses integer & DataHighway uses ascii.
- Server source now contains a new structure - pdstrans.  This is a struct to
  encapsulate a complete PLC transaction (query & response).  This struct is
  now passed around the server's functions instead of the separate parameters.
- Changed all the #def's, functions, structs etc. in the PLC config scanner
  so that it is no longer ModBus specific.  It is now a generic PLC config
  scanner (ModBus, DataHighway at present).
- New server header - pds_utils.h - for utility defines etc.
- Changed the name of the PLC config file.  It was mb.cnf, now plc.cnf.
- Changed the function names in the PLC config file.  Rather than ModBus
  specific (CS_READ, HR_READ etc.) they are now generic (BREAD, WREAD etc.).
- Each driver now has a routine to map between the generic PDS functions & the
  equivelent function for the driver's particular protocol.
- Block lines in the PLC config file can now begin with a forward slash (/)
  as well as the previous method of a caret (^).
- New header files to define the functions & protocols handled by the PDS,
  pds_functions.h & pds_protocols.h.
- PLC config scanner now has 2 lookup tables, 1 for functions & 1 for protocols
  making it easier to add new ones.  Lookup structs defined in utils header.
- Completely overhauled the PDS's queries struct.  Now easier to manage.
- Removed the serial ASCII control char #def's from the DH driver & put them in
  the PLC comms module header as they are generic.
- Added some permanent hex. debug output of the query & response byte arrays in
  the drivers.
- DH driver now quits plc query function with an error if it is unsuccessful in
  reading a query ACK or the response (so it doesn't try indefinitely).
- More #def's in the MB header instead of hard-coded values in the driver.
- Began adding pure serial comms support to the PDS.  The plc comms module has
  a new function 'open_plc_tty()' to open a serial port for comms.  Began
  adding serial read/write functions to the MB driver.
- Re-designed the query/response building/parsing.  The transaction structure
  now contains a new buffer (buf) which is used to build up the specific query
  that is to be run & the PLC's response is also read into this buffer.  What
  that means is that the query contains purely the protocol (MB or DH) & the
  buffer contains the query with its transport-dependent prefix/postfix etc.
  Similarly, on return from comms with the PLC the buffer contains the response
  with its TD prefix/postfix & the response contains only the pure protocol
  reply.  This makes it easier to use the same code to build (say) a MB query
  INDEPENDENT of the comms sub-protocol.
- Made some general mods. to the debug library module, specifically to allow
  multiple levels of debugging rather than the abortive method previously used
  of trying to turn debugging on/off at runtime using signals!
- Mod. the PDS control script (pds) to allow passing of an optional debug
  level to control debug output (see above).
- Minor mod. to pds_io.c.  If an optional debug level (see above) of 4 is
  passed, then the PDS has a short pause after running each read query.
- Mod. PLC config scanner.  Now reads a double quoted TTY device path
  (e.g., "/dev/ttyS1") in place of an IP addr:port if PLC is attached to a
  serial port.
- Made some general, minor mods. to pdsconn, pdstag & pdsquery.
- In PLC comms module, mod. the function to open a tty port, added functions
  to close, read & write tty ports.
- In main I/O module, implemented a generic connect/disconnect interface to a
  PLC so as to talk to a serial or network PLC.
- Added serial code to the DH driver.
- Added serial code to the MB driver.
- Overhauled the makefile hierarchy.  The "user.group" is now passed from the
  top-level makefile to the sub-makefiles.  The sub-makefiles also have
  default build directory/owners in case of not running top-level make.
- Tested the new value member of the tag struct.  Ok.  Incremented the FE/BE
  protocol version as this is not backwards compatible.
- Overhauled the source directory structure (specifically, the APIs' headers
  are under 'include' & the APIs' source are split into different directories
  under 'interfaces').
- Restructured the 'C' API & the PDS's headers.  The headers needed by the
  PDS are more independent of those needed by client programs (via the API).
- Overhauled the 'C' API.  ALL public functions now begin with 'PDS'.  Also
  modified some functions so that the return value is consistent across all
  functions in the API (0 == success, -1 == error).  The connect routine now
  always returns a 'pdsconn' struct (unless, of course, it couldn't be
  malloc()'d) & the client has to interrogate the connection's status (using
  the macro 'PDScheck_conn_status(conn)') to determine if the connection was
  successful or not.
- Modified the Tcl/Tk interface as this is based on the 'C' API.  These mods.
  were internal.
- Overhauled the whole build process.  In keeping with other source packages
  the build process is now: ./configure; make; make install
- Now builds the Tcl/Tk interface only if specified at configure time.  Also
  builds the utilities that use the curses library only if a curses library
  was found at configure time.
- Moved all the 'auxillary' autoconf files (config.guess, acconfig.h etc.)
  into a sub-directory (auto-configure) of the toplevel source directory.
  This cuts down on the clutter in the toplevel directory.
- Changed the internal storage for PLC data (tagvalues).  They WERE encoded as
  an ASCII string representation of the data but are NOW stored as an unsigned
  16-bit word (unsigned short int).  This is much less wasteful on memory and
  should allow for faster updating/retrieval.
- Before making the above modifications to the internal storage a new test
  utility was developed to test the impact of such changes:
  'regression_test.c'.  This is quite basic & is only for use during
  development but could be further developed.
- Incremented the FE/BE protocol version as the above modifications to the
  internal storage are not backwards compatible.
- Implemented a global index that points to the 1st tag of a specified block.
  A new data member of the 'pdstrans' struct - 'block_start' is then set using
  this index (via an accessor macro) before refreshing the block's data tags.
  This avoids the need for a sequential scan of the shared memory to find the
  start of the block.
- Modified/added command line options.  The command line option to specify the
  PDS's data directory is now '-D', which is more obvious (it was '-i').  Also
  a new option '-r {all|block}' sets the PDS's refresh mode.  If set to 'all',
  then the PDS locks the shared memory for the duration of refreshing the whole
  shared memory segment.  If set to 'block', then the PDS locks the shared
  memory segment on a block-by-block basis.