Nordic ID

Using a proper set of RF and inventory settings is mandatory for reaching the optimal reading

performance. RF settings are the main settings that influence how the RF transmitter operates within

Brady EXA81. For example, settings like TX output power level and RF link profile are adjustable.

Applications like the RFID Demo can be used for changing the settings. Settings are also exposed by

the software API of the device.

TX Power level

The maximum TX output power of the Brady EXA81 is 30dBm (1000mW). The power can be adjusted

by 1dB steps via Nur API. In total, there are 30 steps yielding the minimum output power value of 1dBm

(1mW). If you have configured more than one antenna to be used, you can set and store individual output

power level for each of the antennas in question. This per antenna output power setting is also available

via API. Note that if per antenna power level is set this overrides the general TX power level setting.

RF Profiles

The Brady EXA81 supports three different kinds of RF profiles. The profiles are Robust, Nominal and

High speed. It’s important to select the correct RF profile based on use case and environment. More

detailed description about the RF profiles can be found below:

Robust

• Robust RF-profile as a name is misleading and is only used for backwards compatibility reasons.

  In the new NUR3-1W module-based devices like EXA81, the profile is for obtaining maximum

  reader sensitivity. This profile uses link frequency of 160 kHz and Miller 8 coding scheme

  providing read rates up to 80 tags/s. Due to the best sensitivity, this profile can be used when

  maximum read range is needed.

Nominal

• Nominal RF-profile is the default setting in readers containing the Nordic ID NUR3-1W UHF

  RFID module. It uses link frequency of 320 kHz and Miller 4 in ETSI lower band regions and link

  frequency of 250 kHz with Miller 4 coding in FCC regions and sub-sets of that. This profile uses

  tight DRM filters and is suitable for environments having a lot of interferences. Nominal profile

  provides read rates up to 250 tags/s.

High speed

• High speed RF-profile is intended to be used in use cases where the highest read rates are

  required. It uses link frequency of 640 kHz and FM0 coding and provides read rates up to 1000

  tags/s. Due to the high data speed, this profile is quite sensitive to interferences. Also, maximum

  sensitivity is decreased compared to robust and nominal profiles.

Region

The reader has pre-defined region settings defining frequency and channel sets for operating under

different radio regulations. Globally the regulations vary depending on the country. Refer to Nur API

documentation for list of pre-defined countries. When module ships from the production it is locked to

pre-selected (based in the SKU) region setting and cannot be changed by the user.

RSSI Filters

The EXA81 has internal RSSI filters which can be used to limit the read range. By applying the filters,

you can set the limits which tag replay must be met to be registered. MIN RSSI –value means that tag

replay signal needs to be equal or stronger than the defined value. Otherwise, a tag is not read. MAX

RSSI value in other hand means that signal strength must be lower than the filter value. There are

separate RSSI filter values for inventory, read and write operations. These can be set individually.

Inventory settings

By selecting the proper RFID inventory parameters, you can optimize the modules reading performance

for different tag populations and use cases.

Q-VALUE

The Q-value defines the amount of open response slots that tags can use per one inventory round.

Number of slots can be calculated by formula 2Q. It is advised to use twice as many slots compared to

the number of tags that you have in your readers reading field simultaneously. Selectable values are 0

– 15 where 0 means automatic Q-value adjustment. In this automatic mode the reader will adjust Q-

value between sequential rounds based on the number of found tags and collisions. By default, the Q-

value is set to 0.

Rounds

While a fixed Q-value (non-zero) is used, the Rounds value defines the number of query rounds done

inside one full inventory round. After every full inventory round the sled will send the read results to the

host. When automatic Q-adjustment is used, the Rounds value adjusts the threshold for exiting the

inventory loop. By default, rounds setting is set to 0. This setting can help the reader to find all the tags

that are in the reading field when using session 0. Because tags that are found in query round 1 don’t

replay in the following query rounds. When using session 1/2/3 this does not make any significant

difference because tags that are read are quiet anyway.

Session

There are 4 session options which you can use when initializing an inventory round. Every session has

two target states; A and B. By default, Gen2 tags are at state A if the tag has not been recently read.

When tag is read it flips to state B and doesn’t reply to the readers query made using target A. The table

below describes the persistence of tag’s state machine when using different session values. For

example, when using session 0 the tag will come back to state A immediately when tag power is lost.

Usually, tag loses the power when the reader stops the inventory round or changes the channel.

Persistence when tag power is ON is not defined by the ISO18000-63 when using session settings S0,

S2 and S3. With session 1 the tag will keep its state over 500ms but less than 5s. With session values 2

and 3 tags will keep its states over 2s when tag power is lost. Time can vary depending on what tag IC

is used.

Default RF settings

A new device has the following RF settings: