Rockwell Automation 56RF RFID System User Manual - Manual (Page 123)

Rockwell Automation Publication 56RF-UM001A-EN-P - October 2011 123
RFID Tag Speed Chapter 12
UIDLow/UIDHigh – Can be used to target only a specific tag for read
operations, otherwise this value would be 0 to read any tag.
Mode x – Specifies the mode of operation for the Continuous Read.
Option Flag – Used to specify the mode of the Read Multiple/ Read Single
Block(s) command.
A 0 value would only read the data requested starting at the address specified, for
the number of blocks specified in the Length field. A value of 1 would read and
return both the security block status and the tag data.
For modes 1…3, users can either set the delay time on their own or they can train
the interface and the transceiver so that the value is determine automatically
based on their system setup and line speed. A delay time of 0 will cause the
interface to send out the command as soon as it sees the input condition go true.
For mode 0, there is no ability to train the system.
Teach Continuous Read Command Objective
This operation is valid only for modes 1…3 and is used to train the interface to
the approximate delay time that should be used before it sends out the read
command based on input conditions and tag speeds.
Operation
Command 8 will be issued from the Controller to place an RFID interface
channel into teach mode.
When first entering Teach Mode (Phase 1), the interface will wait for the input
condition(s) to go true, and then poll for tag detection. Once 10 good detections
have occurred the unit will enter phase 2.
During Phase 2, the unit will wait for the input condition(s) to go true, then issue
the Read Multiple/Read Single Block command after the predetermined time
delay and adjust the delay time as necessary. Once 10 good reads in a row have
occurred, the unit will exit teach mode and report back the average and
recommended delay time in milliseconds.
If the interface is unable to obtain 10 good reads in a row, it will decrement the
delay time by 1ms and start again in phase 2. If the delay time has been
decremented more than 30 ms from the average the interface will exit teach mode
and report back the recommended delay time of -1. A -1 value indicates that the
interface cannot determine what the best delay time would be due to variations in
tag speed.
Phase progression in teach mode can be monitored by viewing the counter value
in the input image table. Phase 1 will always be a value <10, Phase 2 will always be
a value >10. Once the counter hits 20 the interface will exit teach mode and
report the average and recommended delay times. The user will need to load the