Protocol Menu
MS-850 Raster Scanner User’s Manual
2-11
2–Menu C
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fig
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Multidrop
Note
: Scanners intended to link up to a Microscan MS-5000 multidrop concentrator
must be configured in standard Multidrop protocol.
Similar to Polling Mode D except that a unique poll address and select address are
required for each multidrop device, and only one host port connection is needed for
up to 50 devices.
Requires a concentrator or controller using RS-485 communications. When Multidrop
is selected, the protocol characters for RES, REQ, etc. are assigned automatically.
User Defined
Note:
A specific ASCII character must not be assigned more than once.
Default:
Disabled
Options:
Disabled, Enabled
Used only with RS-232. User Defined is necessary when a new protocol must be
defined to match a specific host protocol. ASCII characters can be assigned as an
address and as protocol commands (RES, REQ, EOT, STX, ETX, ACK, NAK, From Host).
In order to enable a handshaking protocol, you must manually assign values where
necessary. When User Defined is selected, the displayed protocol commands match
those of the previously selected protocol. User Defined is considered to be in a polled
mode only if an address has been assigned. The address can be any ASCII character
from the ASCII table. If null is selected as the address, the scanner will not function in
a polling sequence.
From Host
Default:
Disabled
Options:
Disabled, Enabled
If enabled, allows the handshaking protocol to be initiated from the host, if unpolled.
Messages sent to the host from the MS-850 will always include the scanner’s defined
protocol. The status of From Host determines if messages sent to the MS-850 from
the host must also include the defined protocol. If From Host is disabled, the defined
protocol is not included. If From Host is enabled, the defined protocol must be
included.
Multidrop Addresses
No two scanners in the Multidrop Network can have the same address.
Each scanner in the network must have an address (from 01 to 50) assigned in its
configuration program.
Each address has its own separate poll and select address (from 1C to 7F hex).
For example, during a polling sequence, Scanner 03 expects a 20 hex (“SP” ASCII poll
character) from the concentrator. And during a select command, it looks for a select
value 21 hex (“!” ASCII select character).
