Microscan MS-7100 User Manual page 38

Chapter 2 Menu Configuration
Selecting:
User Defined
Multidrop
Note: A specific
ASCII character
must not be as-
signed more
than once.
a. Once the scanner is configured for Multidrop, a terminal connected to the auxiliary RS-232
pins or a default procedure must be used to access the configuration menus again (although
serial commands will continue to function).
b. For example a simple ACK/NAK protocol can be developed by first selecting Point-to-Point,
then User Defined, and then assigning characters to ACK and NAK commands. First scroll
to the following command:
HOST PROTOCOL --> PROTOCOL --> USER DEFINED--> ACK = -->
Enter a ^F by holding down the Control key while pressing the F key, and then press CR to
see the following:
HOST PROTOCOL --> PROTOCOL --> USER DEFINED --> ACK = ^F
The mnemonics ACK and NAK replace the default NULs in the menu.
Note: Definitions of commands in User Defined and User Defined Multidrop
must be duplicated in host applications to enable poll and select sequences to
execute correctly during transmission.
Typically, parameters in User Defined Multidrop are defined by first
enabling Multidrop, then enabling User Defined Multidrop. This pre-loads
Multidrop characters into the parameters. You then change individual char-
acters to match the host or other requirements.
Preamble
Default: ^M (and a null). Corresponds to <CR><NUL> (carriage return/null)
displayed in the menu.
Options: Any ASCII character, including control characters. Control charac-
ters entered in the command line are displayed in the menu as mnemonic
characters. (See
"Multidrop Address Characters," on page
Allows you to define a one or two character data string that can be added to
the front of the decoded data. For example, defining a carriage return and
line feed would cause each decoded message to be displayed on its own
line.
If User Defined, Polling Mode D, or Multidrop is enabled, the Preamble and
Postamble characters are transmitted within the STX and ETX data block.
2-8
MS-7100/7180 Industrial Scanner User's Manual
Has this effect:
Used when connecting to a concentrator or other device that
does not match standard Multidrop protocol.
Any single character (01 hex to 7E hex) in the ASCII table
can be assigned as the address character. The character
chosen is used as the poll character and the subsequent
ASCII character becomes the select character. For example,
if a ^A (01 hex) is selected as the address, ^B (02 hex)
becomes the select address that the host will use in sending
host select commands. (See Table A-3, "Multidrop Address
Characters," on page A-24.)
"Defining Special Characters" on page 2-4
A-24.)
and Table A-3,