Microscan MS-810, User Manual

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Chapter 2
2-10
MS-810 Industrial Scanner User’s Manual
2–Menu Conf
ig
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Daisy Chain Mode
In a daisy chain application, a primary scanner is linked
directly to the host and succeeding scanners are linked in
tandem. The source of transmitted data can be identified by
enabling and assigning daisy chain IDs to each scanner.
Just before sending a noread message, the primary scan-
ner checks its auxiliary port for data. It waits a maximum
of 20 ms. If no character is received in 20 ms, it sends a
noread message to the host. If a complete message is received, it is sent to the host
instead of the noread message. If for example the primary scanner were set to timeout
in 100 ms, the first succeeding scanner could be set to 90 ms, the next to 80 ms, etc.,
thus assuring that a minimum of 20 ms elapses between transmissions.
Daisy-chained scanners can send a series of labels by enabling Multilabel and a com-
mon multilabel separator. If the primary scanner does not receive the expected num-
ber of labels, noread messages are appended to the data string to make up the
difference between the number of labels enabled in Multilabel (Number of Labels) and
the number of labels read.
For example, a primary and two succeeding scanners have Number of Labels set to 3
and Multilabel Separator defined as %. If the primary and the first succeeding scanner
do not find labels, but the next succeeding scanner registers a good read, the trans-
mitted results would be:
label data % noread % noread .
The conditions for a daisy chain application are as follows:
1. The primary scanner’s trigger can be serial or external; the succeeding scanners
are automatically serially triggered.
2. All scanners are enabled to daisy chain mode.
3. Each scanner’s
Aux port must have its Send and Receive connected to the Host port
of its succeeding scanner.
4. Each succeeding scanner in the daisy chain must be set to send its data no less
than 20 ms before its preceding scanner.
5. All but the primary scanner must have Postamble set to CR (^M) and enabled.
6. All but the primary scanner must have their noread messages disabled.
7. If Multilabel is enabled, Multilabel Separator characters and Number of Labels must
match in all scanners in the daisy chain.
8. Symbology ID enable/disable must be the same in all scanners.
9. All but the primary scanner must have their diagnostic warning messages disabled.
Host
Succeeding
Scanner(s)
Primary
Scanner