Register values may be written using binary, decimal, hexadecimal, or
floating-point notation, depending on the preference selection currently
in effect.

Pressing the Update Button in either write data point dialog will initiate
the appropriate MODBUS write command, (05 or 06), during the next scheduled
poll.


4.2	Message Counters
Each document maintains a counter for each query message transmitted to
a modbus slave device and a counter for each correct response returned
from the addresses slave.  The counters for a given document may be reset
via a button control accessible via the upper, (data definition), splitter
view.  A total count of all message counters from all active documents,
(including any OLE Automation client documents), is displayed via the
ModScan status bar.  

4.3	Observing Serial Traffic
Use this command to troubleshoot the connection to a particular modbus
device.  When selected, this option will display the serial data exchanged
between the ModScan application and the slave device associated with this
document.  The data display splitter view will show data transmitted to
the slave device and data returned from the slave device as communications
occur during the normal polling cycle.  This will help to isolate a problem
with possible misinterpretation of the modbus protocol.  Data will be
displayed in either decimal or hex, depending upon the preference settings
in effect for viewing the modbus data points.  Normal data collection,
(if enabled), will continue.

4.4	Capturing Data to Text File
An optional feature of ModScan is its ability to capture modbus data
directly into a database.  The Microsoft Jet database engine allows
you to automatically update a compatible database with new data each
time it is read by a ModScan document.  Included within a database,
the data is easily accessible for manipulation and display of customized
applications.  Even without this option, ModScan may be used to capture
data to an ASCII text file , which may then be ported in an off-line
fashion to your database.

4.5	User Defined Commands
Use this command to customize a command string for transmission to a
designated modbus slave device.  This command is useful for observing
the slave response to non-standard modbus queries or to test its reaction 
to requests for data which may not be available.  The slave device should
respond with the proper exception message if a master device asks for
data which is beyond its address range or otherwise unavailable via the 
modbus.  

After transmitting the user string, ModScan will receive characters for
the entire time-out period specified for the connection.  The results
will then be updated to the appropriate edit control on the dialog box.
User defined messages transmitted to a slave device will not show up
in the ModScan message counters.


4.6	Scripts

Test scripts are one of the most unique features of ModScan.  They provide
for production testing of modbus slave devices by allowing you to construct
and execute a series of modbus messages to be sent to an attached slave
device to verify and log the responses.  Script files are constructed
using any word-processor or spreadsheet application to define the test
message and expected slave response.  Response codes are available which
determine how ModScan verifies the response against the user supplied data.
For example, one script entry may request the contents of a group of known
registers and expect the exact response to be returned.  Another script
entry may complete successfully if the correct number of register values
is returned, regardless of the contents.

Test scripts may be executed one entry at a time, (single-step), or
placed in a loop to execute continuously, logging the results to a text
file for later observation by a test technician.

If continuous execution of the script is desired, an auxiliary dialog box
defines the looping characteristics.

Test results are displayed as each script entry is executed.

5. 	Using ModScan with a Database
An optional feature of ModScan32 allows you to write data directly into
a Microsoft compatible database such as Access.  ModScan uses the Jet
database engine to provide an efficient exchange of information from an 
addressed slave device into the designated database table.  Selecting the
Dbase Capture menu ietm allows you to associate a ModScan document with
a given database table.  The table will then be updated with new data
each time the slave device is polled.  If you change the properties of
the document while collection is enabled, updates to the database will
temporarily cease.  Database updates will resume if the original 
properties are restored.

6.	Using OLE Automation

6.1	Overview
An optional feature of ModScan32 is the ability to access modbus data
using OLE Automation routines.  This allows custom programs to be
generated, (using Visual Basic, Excel Basic, etc.,), to interpret and
format data according to your specific requirements. OLE Automation
routinesHID_OLE_ROUTINES provide both read and write access to one or
more modbus slave devices through the ModScan application.

Using the OLE Automation routines is a very simple process:

The VBA application links to the ModScan32.tlb file, (Type Library),
which details the names for each automation procedure and its argument
list.  From the Visual Basic development framework, this is done by
selecting the menu item to include a custom type library and then
browsing for ModScan32.tlb.  During the initial Form Load operation,
the application must call Create Object as follows:

CreateObject("ModScan32.Document")

The application then creates one or more PollRequests which define an
array of data points to be read from a modbus device.  Data defined by
the Poll Request will be automatically scanned by the ModScan application
on a 1 second basis.  (NOTE:  The ModScan application must be connected
to the modbus network prior to the VBA application starting up.)

The application uses the handle returned from the CreatePollRequest
procedure to access, (read or write), a value within the defined array.

During application termination, it must free the memory used by the
ModScan application to maintain the data points by deleting any Poll
Requests created.

Refer to the Visual Basic Example application included with the ModScan 
distribution files for additional details.

6.2	Automation Routines

The following OLE Automation routines are supported by ModScan32:

short CreatePollRequest (short Device, long Address, short Length)
	Arguments:
		Device - Specifies the slave device address
		Address - Specifies the data point address,
				(in modbus master  (5 digit) format.
				coil status addresses: 	00000-09999
				input status addresses: 	10000-19999
				input register addresses: 	30000-39999
				holding register addresses: 	40000-49999
		Length - Specifies the number of values included in the 
			definition
	Return Value:
		Point Handle - Defines the array structure for future 
				reads	& writes
	Notes:
		Sets up data structures within ModScan to begin polling the
		specified data.  ModScan must be connected to the modbus
		network prior to creating the data array.  CreatePollRequest
		returns a non-zero value if the data structure was successfully
		created, otherwise it returns 0.

short ReadValue (short PointHandle, short Index, short  *pValue)
	Arguments:
		Point Handle -  refers to value returned from CreatePollRequest
		Index - Specifies the index into the array structure
		*pValue - is a pointer to a value to be returned.
	Return Value:
		Status - indicates whether or not the operation was completed
				successfully
	Notes:
		Status will be MBUS_OK, (0), if the data point was
		successfully read, otherwise, a  non-zero value 
		indicates one of the defined error conditions.

short WriteValue (short PointHandle, short Index, short  Value)
	Arguments:
		Point Handle -  refers to value returned from CreatePollRequest
		Index - Specifies the index into the array structure
		Value - is the data to be written.
	Return Value:
		Status - indicates whether or not the operation was completed
				successfully
	Notes:
		Status will be MBUS_OK, (0), if the data point was successfully
		queued for transmission to the addresses slave.  A zero return
		value does not indicate successful transmission of the request
		to the slave device.  The controlling application is responsible
		for verifying the write operation by reading back the value
		written.

short ModifyPollRequest (short PointHandle, short Device, long Address, short Length)
	Arguments:
		Point Handle -  refers to value returned from CreatePollRequest
		Device - Specifies the new slave device address
		Address - Specifies the new data point address,(in modbus
				master  (5 digit) format.
		Length - Specifies the number of values included in the
				definition
	Return Value:
		Status will be MBUS_OK, (0), if the data point was successfully
		modified, otherwise, a  non-zero value indicates one of the
		defined error conditions.
	Notes:
		Immediately after changing the parameters of a defined data
		point, the current status of each value in the array will be
		set to MBUS_UNINITIALIZED, indicating that the data does not
		represent that defined 	by the device/address definition.
		The first poll after modification should reflect the true
		status of the addressed data array.

short DeletePollRequest (short PointHandle)
	Arguments:
		Point Handle -  refers to value returned from CreatePollRequest
	Return Value:
		Status will be MBUS_OK, (0), if the data point was successfully
		modified, otherwise, a  non-zero value indicates one of the
		defined error conditions.
	Notes:
		This routine frees up memory allocated by ModScan to support
		the defined Poll Request.



7.	Distribution/Registration


7.1	Pricing
ModScan is a time-limited demo application which allows you to connect
up to a modbus network and evaluate its operation without cost or
obligation.  ModScan is designed to allow unrestricted use for a period
of 3 1/2 minutes after successful communication is established with a
slave device.  During this time, all features, including OLE and database
support are active.  At the end of the demo period, ModScan will cease
updating the views associated with each document.  You must restart
the application to resume operation.

The introductory registration price for the ModScan32 application is $64.95.
Options to allow interfacing data to a database and/or OLE are additional.
ou may print an order form by selecting a button control within the
ModScan About box.  

For the latest pricing and availability details, please refer to the
WinTECH Software Web-Site at http://www.win-tech.com

7.2 	Licensing
ModScan32 is distributed as a shareware/demo-ware application which may
be freely distributed without charge to prospective users.  Time limits
and registration reminder screens are utilized to encourage registration.
If you find this application useful, please refer it to your associates
in the hope that they too may be able to use it.

If you choose to register this application, you will receive a license
certificate with access codes which will remove all program restrictions
when entered into the initial sign-on dialog box.  You will only need to
enter the registration codes once.  A single-user license allows the
purchaser to use the application on as many different machines as desired,
so long as there is only one copy of the application running at any given
time.  Running multiple instances of the application on different machines
at the same time is a violation of the copyright owned by WinTECH Software.
Multiple-User and Site-licenses are available for installations which
require multiple simultaneous use of the ModScan application.

7.3	Support
For the latest product and pricing information, please refer to the
WinTECH Software Web-Site at:

http://www.win-tech.com


For technical support, please e-mail:   
support@win-tech.com

To place an order, fax to:  
1-304-645-5966

or mail:	
WinTECH Software
P.O. Box 907
Lewisburg, WV  24901
U.S.A.

7.4	Other Products
WinTECH Software offers the following products and services which may
be of interest:

Modbus Driver Dll's
	Windows drivers are available to support either the modbus master
	or modbus slave protocol on a PC.  These drivers are written in 'C'.
	They are available in either 16 or 32-bit designs and include all 
	modbus message formatting and interaction with the Windows serial
	drivers.  A simple API is made available to your application, which
	greatly simplifies its design and allows you to very easily 
	implement a custom modbus design under Windows.  Each driver is
	very reasonably priced, and comes with a sample Windows application
	written in the Microsoft MFC.

ModSim Windows Application
	ModSim is the counterpart to ModScan and simulates the slave end of
	the modbus protocol.  ModSim allows you to define a series of data
	points, (representing one or more slave devices), and provides 
	this data to an attached modbus master application.

MNetSvr Windows Application
	MNetSvr is a Windows application which serves as a Modbus to TCP/IP
	gateway device for interfacing serial modbus slave devices to plant
	networks.  MNetSvr utilizes the MBAP protocol standard, (Modbus
	Application Programming Interface), to service multiple Modbus
	Master Client applications requesting data from one or more slaves.

Listen Windows Application
	Listen is a fully functional serial data link monitor, (datascope),
	which allows you to watch data traffic in real time as it travels
	in two directions between communicating devices. Listen is highly
	customizable in the way it displays data and uses standard COM
	drivers for compatibility with any serial hardware configurable
	under Windows.

Socket Spy Windows Application
	The Socket Spy allows you to monitor TCP/IP packets transferred
	between a Windows application and the Windows Sockets dll.  Designed
	as a design and trouble-shooting aide for communications developers,
	Socket Spy provides full debugging data relative to all sockets
	activity occurring within the target application. 

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