Instruction Manual

36
Extended Options
The Setup Extended Options menu offers the following commands:
Force Coils
Provides the ability to write coil values to a designated slave device. Use this
command to manually force a group of coils to a given state, (on/off). The
ability to address multiple coils in a
slave depends upon the operating characteristics of the device. ModScan uses
modbus message 15, (Force Multiple Coils), to transmit the request to the
designated slave. Selecting this menu option will initiate a dialog box which
prompts for the address of the data to write:
Entering appropriate values for the slave address, point address, and number of
coils to write initiates a second dialog which allows you to manually select the
value for each coil. Use the radio buttons to select either ON of OFF for each
coil value. The scrollbar control allows you to advance to the next series of coil
addresses:
Preset Registers
Provides the ability to write register values to a designated slave device. Use this
command to force a group of holding registers to selected values. ModScan
uses modbus message 16, (Preset Registers), to write data to the designated
slave device. Selecting this menu option will initiate a dialog box which prompts
for the address of the data to write:
Entering appropriate values for the slave address, point address, and number of
registers to write initiates a second dialog which allows you to manually select
the value for each register. Use the edit controls associated with each register
address to enter its value. Values may be entered in either decimal or
hexadecimal notation, depending upon the preference selected for modbus data
display. The scrollbar control allows you to advance to the next series of
register addresses up to the maximum specified in the previous dialog:
Buttons at the right of the Preset Registers dialog allow you to configure a series
of register values and write them to a disk file for later retrieval and
downloading to a modbus slave. Pressing the To File button saves the currently
defined register values to a selected file. The From File button fills the edit
controls of the dialog with values obtained from a previously saved disk file.
User Commands
Allows you to define and transmit a custom command. 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.
Mask Write
This menu selection provides support for the modbus Write-Mask function,
(command 22), which allows you to specify a bit pattern to be used in updating
the contents of a holding register.
Script Files
Begins execution of a test script.
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