Daisy Chain Mode - Microscan MS-3 User Manual

Daisy Chain Mode

Usage: Useful in applications where:
• A symbol might be scanned in both ladder and picket fence directions.
• A symbol may be present on multiple sides of a package.
• Symbols are presented at different depths.
Definition: In a daisy chain application, scanners are connected in tandem or "daisy
chain" and decoded data is relayed from one scanner to another on up to
the host.
A master scanner has its host port linked to the host computer and its
auxiliary port linked to the host port of the first "slave" scanner in the
chain. Thereafter, each slave's auxiliary port is linked to the host port of
the slave that is further from the host in the daisy chain.
Each scanner in the daisy chain can be assigned an ID that accompanies
any data that it sends.
Serial Cmd: <K101,aux port
ID status,daisy chain ID>
Options: 4 = Daisy chain
Function: Before the master scanner times out, it checks its auxiliary port for data.
It should be set to wait at least
(See
within the read cycle timeout, the master sends a noread message to the
host. Otherwise the complete data is sent.
If for example a master scanner is set to timeout in 120 mS, the first
slave scanner might be set to 100 mS, the next to 80 mS, and so forth,
thus assuring that at least 20 mS elapses between transmissions.
Daisy-chained scanners can send a series of symbols by enabling Multi-
symbol and a common multisymbol separator. If the master scanner
does not receive the expected number of symbols, noread messages are
appended to the data string to make up the difference between the num-
ber of symbols enabled in Multisymbol and the number of symbols read.
For example, a master and two slaves have Number of Symbols set to
3 and Multisymbol Separator defined as %. If the master and the first
slave do not find symbols, but the next slave scanner registers a good
read, the transmitted results will be: symbol data % noread % noread.
a. The above example is based on the best case. Other factors such as baud rate, dynamic focus timing,
number of characters in a given symbol, and the number of slaves in the daisy chain can affect tim-
ing and may need to be included in your calculations for complete accuracy.
mode,baud rate,parity,stop bits,data bits,daisy chain
"Read Cycle Timeout" on page
Chapter 3 Communications
20 mS for each slave in the daisy chain.
4-15.) If no data is received
MS-3 Laser Scanner User's Manual
a
3-17