Specifications

Table Of Contents

Communications Timing

26 SkyePlus™ MXH and MXU Multiplexer Reference Guide

Communications Timing

With SkyeTek firmware, the host controls all port switching. The host determines

which port is activated and when. The MUX Control system parameter lets you

control this functionality.

Switching speeds for hardware components on the

multiplexer are on the order

of a few hundred nanoseconds. However, when you use the multiplexer with a

SkyeModule reader communicating through the firmware, these timings are

affected by factors including the tag protocol, the number of tags in the field, and

the setting for the number of retries. In general, the more tags that are in the read

field and the higher the setting for the number of retries, the longer it takes to

complete tag commands at each port.

The following example illustrates a timing s

equence for a port change with a

SkyeModule M9, configured as follows:

● SkyeTek Protocol v3

● RS-232 communication

● 38400 baud

● Select Tag command

● Inventory mode

● Gen 2 protocol

● Number of retries set to three

● Four tags in the field

In this configuration the total switching time per port is ~150ms. This equates to

1.6 cycles/second to switch a four

-ports multiplexer or 0.8 cycles/second to

switch an eight-ports multiplexer.

Figure 4-1shows the typical timing of communica

tions between host and reader,

and Table 4-1 on page 27 describes each timing component.

Time

...

Figure 4-1 SkyeTek Protocol Timing Diagram