RFID read / write power setting system and method

Abstract

A system and method for configuring radio frequency identification (RFID) read and write power levels, comprising: an RFID module that generates an RF signal, a digital step attenuator that attenuates the RF signal, an antenna that transmits the attenuated RF signal, and an RF shield that isolates the antenna from a supply roll of RFID tags. A lower limit read power is determined by repeatedly interrogating an RFID tag while reducing the RF signal power until the tag fails to respond to the interrogation. An upper limit read power is determined by repeatedly interrogating the RFID tag while increasing the RF signal power until multiple tags respond to the interrogation. The read power level is set between the lower limit read power and the upper limit read power. The write power level is determined by repeatedly attempting to program the RFID module while increasing the write power from the read power level until successful writing.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Patent Application No. 62 / 889,218 filed on August 20, 2019, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] The subject matter of the present application generally relates to configuring RFID power levels for communicating with RFID tags, and more particularly to dynamically determining optimal power settings for an RFID printer so that a single RFID tag can be read and programmed during printing without reading or programming nearby RFID tags. Background Art

[0004] Radio frequency identification (RFID) tags typically include an antenna coupled to an RFID chip. RFID tags typically receive power from a nearby RF source, such as an RFID reader or RFID printer that transmits RF energy at the resonant frequency of the RFID tag. When interrogated by an RFID reader, the RFID tag receives power from the RFID reader and sends a coded return signal. RFID readers can also program RFID tags in a similar manner.

[0005] Some RFID printers can print multiple RFID labels from a blank label supply roll. Each RFID label is generally individually configured when the label is printed. In order to prevent the multiple blank labels on the supply roll from being accidentally configured while one of the labels is being printed, the RFID write power level is generally maintained at a low power level and the supply roll is electrically isolated from the RFID printer's RF antenna. However, at low power levels, some RFID labels may not be consistently programmed during the printing process. In addition, different types of RFID labels may have different sensitivities, which may require different write power levels to be used for different types of RFID label supply rolls. Summary of the invention

[0006] In some aspects of the present invention, an embodiment is directed to a method, the method comprising: setting a read power level of a radio frequency identification (RFID) device to an initial power level; determining a floor read power level by repeatedly interrogating an RFID tag with the RFID device while reducing the read power level until the RFID tag fails to respond to the interrogation, or the read power level reaches a minimum power level; determining a ceiling read power level by repeatedly interrogating the RFID tag with the RFID device while increasing the read power level until a second RFID tag responds to the interrogation, or the read power level reaches a maximum power level; and configuring the read power level of the RFID device based at least in part on the floor read power level and the ceiling read power level.

[0007] In other aspects of the present invention, embodiments are directed to an apparatus comprising: a radio frequency identification (RFID) module configured to generate a radio frequency (RF) signal; a radio frequency (RF) attenuator configured to attenuate the RF signal; a radio frequency (RF) antenna configured to transmit the attenuated RF signal; and a controller configured to set a read power level of the attenuated RF signal to an initial power level via the RF attenuator, determine a lower limit read power level by repeatedly interrogating an RFID tag with the attenuated RF signal by the RFID module while reducing the read power level via the RF attenuator until the RFID tag fails to respond to the interrogation or the read power level reaches a minimum power level, determine an upper limit read power level by repeatedly interrogating the RFID tag with the attenuated RF signal by the RFID module while increasing the read power level until a second RFID tag responds to the interrogation or the read power level reaches a maximum power level, and configure the read power level of the attenuated RF signal based at least in part on the lower limit read power level and the upper limit read power level.

[0008] Other aspects of the present invention include, but are not limited to: a method for determining a read power level for an RFID tag; a method for determining a write power level for an RFID tag; an RFID antenna and a controller configured to determine read and write power levels for an RFID tag; a radio frequency shield configured to isolate the RFID antenna from an RFID tag supply roll; and an RFID printer configured to determine the power level used to interrogate and program a single RFID tag from an RFID tag supply roll. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a schematic diagram of an example portable RFID printer.

[0010] Figure 2 is a schematic diagram of an example portable RFID printer with an internal RFID antenna for programming individual RFID tags from a supply roll of RFID tags.

[0011] Figure 3 is a functional block diagram of an RFID printer according to an embodiment of the present disclosure.

[0012] Figure 4 is a functional block diagram of a combined RFID printer and RFID reader according to one embodiment of the present disclosure.

[0013] Figure 5A and Figure 5B The flowchart is two parts of an example operation of a system for dynamically configuring RFID read and write power levels according to one embodiment of the present disclosure.

[0014] Figure 6 is a cross-sectional view of an exemplary portable RFID printer.

[0015] Figure 7 is a schematic diagram of the antenna, printing and shielding components of an exemplary portable RFID printer.

[0016] Fig. 8A is a first schematic diagram of RFID tags from a supply roll of RFID tags.

[0017] Figure 8B is a second schematic diagram of RFID tags from a supply roll of RFID tags. DETAILED DESCRIPTION

[0018] The systems and methods disclosed herein are illustrated by way of example and with reference to Figures 1 to 8B It will be appreciated that the disclosed and described embodiments, arrangements, configurations, components, elements, devices, equipment, methods, systems, etc., may be appropriately modified and may be desired for a particular application. In this disclosure, any identification of specific techniques, arrangements, etc., either relates to the specific examples mentioned, or is merely a general description of such techniques, arrangements, etc. The identification of examples or specific details is not intended to be, and should not be construed as, mandatory or restrictive unless specifically specified.

[0019] The present disclosure illustrates new modalities for determining optimal power levels for reading and writing individual RFID chips on an RFID printer. The systems and methods disclosed herein describe various aspects of determining and configuring read and write power levels so that only selected RFID tags are targeted, while other RFID tags (such as an internal supply roll of blank RFID tags) are not accidentally written or read by the RFID device.

[0020] RFID devices that can operate in different frequency bands are generally designed for different functions and are usually manufactured separately. RFID devices can be used for many different purposes, including, for example, item identification, item tracking, and inventory counting. As can be appreciated, an item may include different RFID devices to provide the respective benefits of each RFID device. Different types of RFID devices may have different sensitivities. Some RFID tags can be reliably interrogated at lower power levels than other types of RFID tags. Some RFID tags require higher write power levels than the power levels required to read the same RFID tag. Still other RFID tags may be able to use a wide range of suitable power levels, while other RFID tags may require power levels within a narrower range. Different types of RFID printers may be better than other types in shielding RFID tags that are still on the internal blank RFID label supply roll.

[0021] RFID printers and RFID readers may need to be configured differently for different types of RFID tags. Rather than manually configuring each RFID printer or RFID reader with a supply roll of each type of RFID tag, the present invention provides a system and method for determining the appropriate read and write power levels to write to a single RFID tag without accidentally reading or writing to unintended RFID tags (such as blank RFID tags loaded on a supply roll inside a portable RFID printer).

[0022] Go to Figure 1 , Figure 1A portable RFID printer 100 is shown. The RFID printer 100 includes: a power source 102, such as a field replaceable battery or a rechargeable battery pack. The RFID printer 100 includes a port 106, through which the printed RFID label exits the RFID printer 100. The RFID printer 100 also includes a display screen 104, which is configured to provide printing details and control options to a user. The display screen 104 is driven by a display controller board, which may optionally include circuits for reading and writing RFID chips. The RFID printer may include one or more other circuit boards, which may alternatively include such circuits as a print control circuit board 110 and a print engine circuit board 112. Any suitable circuit board, controller or electronic module assembly can be used as understood in the art. An exemplary portable RFID printer is a 6059 printer from Avery Dennison Corporation of Glendale, CA. However, it should be appreciated that other RFID printers are also alternatively applicable, including non-portable RFID printers.

[0023] Now go to Figure 2 , Figure 2 Show Figure 1 1 is an internal view 200 of a portable RFID printer 100. In this internal view 200, an example antenna 202 for programming an RFID label 206 is shown. Individual RFID labels 206, also known as RFID tags, are printed from a label supply roll 204. Each RFID label 206 includes: an RFID antenna 210 and an RFID chip 208 disposed on a suitable substrate (such as a plastic substrate, a polyethylene terephthalate (PET) substrate, a paper or paperboard substrate, a polyethylene substrate, etc.). The RFID chip 208 is electrically coupled to the RFID antenna 210. Figure 2The RFID antenna 210 of the example RFID tag 206 shown uses a coil antenna. RFID tags using coil antennas typically operate in the high frequency (HF) spectrum, such as at or near 13.56 MHz, and are primarily designed to be driven by near magnetic field readers (such as those classified as handheld readers). RFID tags using monopole or dipole antennas can operate in the ultrahigh frequency (UHF) spectrum, such as 865 MHz to 869 MHz, or 900 MHz to 960 MHz. Other types of RFID tags may be used as understood in the art. The RFID label 206 may include printing on one side thereof (not shown). Because the label supply roll 204 is adjacent to the antenna 202, it is important to properly control the read and write power levels to ensure that the antenna 202 only reads or programs a single RFID label 206 adjacent to the antenna 202. If the power level is too high, or if the supply roll 204 is not properly isolated from the antenna 202, the antenna 202 may inadvertently read or program multiple RFID tags 206 (such as those on the supply roll 204).

[0024] Now turn to Figure 3 , Figure 3 A functional block diagram of a first system 300 for controlling read and write power levels is shown. The system 300 may include: one or more host controllers 302, which provide data for programming the RFID chip. Example host controllers 302 may include servers, cloud-based services, etc. A local controller 306 on an RFID printer (such as a portable RFID printer) communicates with the host controller 302, for example, when a user operating the portable RFID printer downloads the data to the RFID printer to print a batch of RFID labels. A power supply 304 (for example, a battery power supply as shown) provides power to the portable RFID printer. Regulators 308, 310 provide the appropriate voltages required for various different components of the portable RFID printer. An RFID reader module 312 generates a suitable RF signal for reading and writing RFID chips on RFID labels. An RF digital step attenuator 314, appropriately controlled by the local controller 306, modifies the power level of the RF signal sent to the antenna 318 to prevent the antenna 318 from reading and writing RFID tags that are not immediately adjacent to the antenna 318, such as with respect to Figure 5A and Figure 5BThe internal isolation shield 316 further isolates the RF signal so that read and write operations are only performed on RFID tags that are adjacent to the antenna 318. The internal isolation shield 316 can also shield the circuit from the RF energy of the antenna 318.

[0025] Now turn to Figure 4 , Figure 4 A functional block diagram of a second system 400 for controlling RFID read and write power levels is shown. The system 400 may include: one or more host controllers 402, which provide data for programming RFID chips. Example host controllers 402 may include servers, cloud-based services, etc. A local controller 406 on an RFID printer (e.g., a portable RFID printer) communicates with the host controller 402, for example when a user operating the portable RFID printer downloads the data to the RFID printer to print a batch of RFID labels. A power supply 404 (e.g., a battery power supply as shown) provides power to the portable RFID printer. Regulators 408, 410 provide the appropriate voltages required for various different components of the portable RFID printer. An RFID reader module 412 generates appropriate radio frequency signals for reading and writing RFID chips on RFID labels.

[0026] The portable RFID printer may be configured with different antennas. For example, an internal near field antenna 418 (such as Figure 2 The RFID antenna 210 of the portable RFID printer can be used to program the RFID tags printed by the portable RFID printer. The external far-field antenna 422 can be used by the portable RFID printer to interrogate RFID tags outside the portable RFID printer (for example, RFID tags attached to merchandise). This configuration allows the portable RFID printer to also be used as an RFID scanner. In some embodiments, the portable RFID printer can use the external far-field antenna 422 to program or reprogram existing RFID tags that may be attached to merchandise or otherwise not present within the portable RFID printer. The RF digital step attenuator 414, appropriately controlled by the local controller 406, modifies the power level of the RF signal sent to one or more of the antennas 418, 422 to prevent the antennas 418, 422 from reading or writing RFID tags that are not adjacent to one of the antennas 418, 422, as described with respect to FIG. Figure 5A and Figure 5B422. The RFID multiplexer 420 distributes the RF signal from the RF digital step attenuator 414 to the antennas 418, 422. For example, when programming RFID tags that are inside the portable RFID printer, the local controller 406 can set the RF digital step attenuator 414 to a first power level, and when configured to scan or program RFID tags that are outside the portable RFID printer, the local controller 406 can set the RF digital step attenuator 414 to a second power level (e.g., a higher power level, as is typical in this case). The internal isolation shield 416 further isolates the RF signal so that read and write operations are performed only on RFID tags that are adjacent to one or more of the antennas 418, 422. The internal isolation shield 416 can also shield the circuit from RF energy from the antennas 418, 422.

[0027] Steering Figure 5A and Figure 5B , Figure 5A and Figure 5B A flowchart 500 is shown of example operations of a system for controlling RFID read / write power levels. Operations begin at start step 502 and proceed to step 504 where an initial RFID test power level and read power level are configured. The process proceeds to step 506 where a read is found and the read power is set to a midpoint between a test minimum amount and a test maximum amount. Any suitable initial power level may be selected. For example, the initial RFID read power level may be configured to be a midpoint between a minimum configurable read power level and a maximum configurable read power level. The initial minimum and maximum power levels may be hard coded or retrieved from a suitable data store, such as a data repository. The process proceeds to step 508 where the system transmits an RFID interrogation signal via a radio frequency antenna of the system, which may be, for example, a Figure 2 Based on the read power level and the proximity of nearby RFID tags, the RFID interrogation signal energizes RFID tags adjacent to the RF antenna, and the system may receive feedback responses from no RFID tags, a single RFID tag, or multiple (or many) RFID tags.

[0028] If, at step 510, no RFID tags respond to the RFID interrogation at step 508, the process proceeds to step 514 to determine whether the read power can be increased by setting the minimum test amount to the read power plus 1. At step 516, if the read power has reached the maximum level, the process terminates at step 518, otherwise, at step 514 the read power level is incremented by 1 and the process continues back to step 506 to perform the RFID interrogation at the increased read power level. The read power level may be incremented at any suitable interval, for example, by Figure 4 The RF digital step attenuator is available in one decibel or one step increments.

[0029] If, at step 510, one or more RFID tags respond to the RFID interrogation, the process proceeds to step 512. At step 510, if multiple RFID tags respond to the RFID interrogation, the process proceeds to step 512 to determine whether the read power can be reduced. At step 512, the read power is reduced by one, and the process continues back to steps 506 and 508 to perform the RFID interrogation at the reduced read power level.

[0030] If at step 510, exactly one RFID tag responds, the process proceeds to step 520 to set the good read power to the read power and the test maximum to the read power minus 1. At step 520, the read power level is reduced. The read power level may be reduced at any suitable interval, for example, by Figure 4 The RF digital step attenuator is decremented by one decibel or one step. In step 522, a lower limit read level is determined by checking at what level an RFID tag will still respond to the RFID interrogation. In step 524, the read power level is set to the midpoint between the test level minimum and test level maximum.

[0031] At step 526, the RFID interrogation is performed at the reduced read power level. If, at step 528, multiple RFID tags continue to respond, the process returns to step 530 to reduce the read power level and perform another RFID interrogation at steps 526 and 528. Once, at step 528, the RFID tag stops responding to the RFID interrogation, or if the minimum read power level is reached, the process proceeds from step 528 to step 532, where the power is increased to the level used when the RFID tag last responded to the RFID interrogation, and this power level is stored as the lower read power level, such as by setting the test level minimum to the read power plus 1. At step 534, if the test level minimum is greater than or equal to the test level maximum, the process returns to step 524. If not, the process proceeds to step 536, where the read level lower limit is set to the test level maximum plus 1, the test level minimum is set to the good read power level plus 1, and the test level maximum is set to the maximum power level. In some embodiments, the lower read level may be set to any suitable level at which the one RFID tag continues to respond, such as by increasing the read level by two or three decibels, or by two or three steps via an associated RF digital step attenuator.

[0032] The process continues to step 540 where the upper read level is the level at which the one RFID tag will still respond to the RFID interrogation while no other RFID tags are also responding. If, at step 542, the test minimum is greater than or equal to the test maximum, the process returns to step 524. If not, the process proceeds to step 544. At step 544, the read power level is increased. At step 544, the lower read level is set to the test level maximum plus 1, the test level minimum is set to the good read power level plus 1, and the test level maximum is set to the maximum power level. The read power level may be incremented at any suitable interval, for example, by Figure 4 The RF digital step attenuator is available in one decibel or one step increments.

[0033] The upper limit level is determined in step 538, and then in step 546, the read power level is set to the midpoint between the test level minimum and the test level maximum. The process continues to step 548, in which the RFID read power level for the system is configured. Any suitable RFID read power level can be selected. For example, the RFID read power level can be configured to be the midpoint between the upper limit read power level and the lower limit read power level. The RFID read power level can be stored in a suitable data storage (e.g., a data repository). In step 548, the RFID interrogation is performed at the increased read power level. If, in step 550, only one RFID tag continues to respond, the process proceeds to step 560 to determine whether the read power level is greater than the read upper limit level. If so, then in step 562, the read upper limit level is set to the read power level, and then in step 564, the test level minimum is set to the read power level plus 1. If not, the process enters step 564, in which the test minimum is increased, for example by setting it to the read power plus 1. In step 566, if the minimum test level is not greater than or equal to the maximum test level, the process returns to step 546; if so, the process enters step 558, in which the read power is set to the midpoint between the lower limit read level and the upper limit read level, and the write power level is set to the read power level.

[0034] In step 550, if no tag is detected, then before entering step 558, the minimum test level is set to the read power plus 1 in step 568, and then in step 558, the read power is set to the midpoint between the lower limit read level and the upper limit read level, and the write power level is set to the read power level.

[0035] Once a plurality of RFID tags begin responding to the RFID interrogation at step 550, or if the maximum read level is reached, the maximum power is set to the read power at step 552. At step 554, if the test minimum is not greater than or equal to the maximum power, the process proceeds to step 556, where the power is reduced (e.g., by setting the test maximum to the read power minus 1) to the power level used when only one RFID tag responded to the previous RFID interrogation, and that power level is stored as the upper read level. At step 554, if the test minimum is greater than or equal to the maximum power, the process proceeds to step 558, where the read power is set to the midpoint between the lower read level and the upper read level, and the write power level is set to the read power level. In some embodiments, the upper read level can be set to any suitable level at which the one RFID tag continues to respond while other RFID tags do not, such as by lowering the read level by two or three decibels, or by two or three steps via an associated RF digital step attenuator.

[0036] At step 569, if the write power level is less than the maximum power level minus 1, the process proceeds to step 572 to configure the RFID write power level. If not, the process terminates at step 570. At steps 572 and 574, if the RFID tag write operation is unsuccessful, the write power is incremented at step 576. If the write power is less than the maximum power minus 1, the process proceeds back to step 572 to perform the RFID write operation at the RFID write power level. At steps 572 and 574, if the RFID tag write operation is successful, at step 578, for example, the write power is increased by 2. The process proceeds to step 580 to determine whether the write power is greater than the maximum level. If so, the process terminates at step 570. If not, at step 582, the RFID read power level and / or write power level may be stored in a suitable data store. The process then terminates at step 584.

[0037] Example pseudo code for determining optimal read and write power levels is shown below:

[0038]

[0039]

[0040]

[0041]

[0042]

[0043] Reference now Figure 6 , Figure 6 A cross-sectional view of an exemplary portable RFID printer 600 is shown. The portable RFID printer 600 includes: an RFID antenna board 602, an RFID tag supply roll 604, a print head retainer 606, a radio frequency shield 608, and a transport roller 610, among other components. The dashed arrows show the path 612 of the RFID tags through the portable RFID printer 600.

[0044] The RFID antenna circuit board 602 acts as an upper feed guide to guide the RFID label from the supply roll 604 along a path 612 into a print nip 614. The RFID antenna circuit board 602 includes an integral RFID antenna for programming the RFID tag as it moves along the path 612 from the supply roll 604 to below the RFID antenna circuit board 602 and into the print nip.

[0045] Due to space limitations in the portable RFID printer 600, the RFID tag supply roll 604 is located in close proximity to the RFID antenna circuit board 602. The RF shield 608 provides RF shielding to isolate the RFID tags on the supply roll 604 so that RFID read and write operations are performed only on the RFID tags below and adjacent to the RFID antenna circuit board 602. While adjusting the strength of the above-mentioned RFID signal, the RF shield 608 helps to ensure that the RFID antenna circuit board 602 does not erroneously couple the RF signal to the adjacent RFID tags on the supply roll 604. The RF shield 608 may include a curved and continuous wall that spans the entire width of the supply roll 604, extending from the RFID antenna circuit board 602 at the bottom to the top of the cavity of the supply roll 604.

[0046] Refer to Figure 7 , Figure 7A selected assembly 700 of a portable RFID printer is shown, including an RFID antenna circuit board 702 and associated RF cable 704, a print head holder 706, an RF shield 708 and associated ground cable 712, and a transport roller 710. The assembly 700 includes features that are configured to facilitate assembly and alignment while also reducing the possibility of jamming. For example, a groove 714 in the RFID antenna circuit board 702 mates with a locating rib 716 in the print head holder 706. Wings 718 on each side of the RFID antenna circuit board 702 mate with retaining notches 720 of the print head holder 706. A retaining clip 722 secures the RF shield 708 to the print head holder 706.

[0047] See also Fig. 8A and Figure 8B , Fig. 8A A first schematic diagram 800 showing RFID tags from a substantially new supply roll 804 of RFID labels, Figure 8B A second schematic diagram of RFID tags from a nearly empty RFID tag supply roll 814 is shown. Fig. 8A In FIG. 8 , the RFID tag 802 includes a slight scalloping effect 806, while in FIG. Figure 8B In the embodiment of the present invention, the RFID label 812 includes a significant fanning effect 816. The fanning effect 806, 816 occurs because the supply rolls 804, 814 are constructed of an internally laminated plastic inlay. When the RFID label 802, 812 is unspooled from the supply rolls 804, 814, the carrier web of the RFID label 802, 812 tends to fan. This is due to the curvature memory induced in the RFID label when the single butt-cut or die-cut RFID label 802, 812 is wrapped around the core of the supply rolls 804, 814. The fanning effect 806, 816 can cause the leading edge of one or more RFID labels 802, 812 to snag on any feature within the supply path and delaminate from the carrier web, causing jamming.

[0048] refer to Figure 7, because the RFID antenna circuit board 702 acts as an upper feed guide across the width of the RFID label. The RFID antenna circuit board 702 guides the RFID label into the printing nip. Any mechanical means of attaching the RFID antenna circuit board 702 to the print head holder 706 (such as countersunk screws, rivets, etc.) will cause protrusions or edges in the feed path, causing the leading edge of the RFID label to be abraded, delaminated, and cause jams. In order to eliminate the protrusions and edges, each side of the RFID antenna circuit board 702 includes a wing 718 extending beyond the feed path. The wing 718 matches the corresponding retaining recess 720 of the print head holder 706. Similarly, the groove 714 in the RFID antenna circuit board 702 matches the positioning rib 716 in the print head holder 706 and is located in an area away from the feed path to eliminate the possibility of abrasion and jams.

[0049] It should be appreciated that the systems and methods described herein are also applicable to other machines and processes as generally understood in the art. Although some embodiments have been described, these embodiments are given by way of example only and are not intended to limit the scope of the invention. In fact, the novel embodiments described herein may be embodied in various other forms; in addition, various omissions, substitutions, and changes may be made to the forms of the embodiments described herein without departing from the spirit of the invention. The accompanying claims and their equivalents are intended to cover such forms or modifications that fall within the spirit and scope of the invention.

Claims

1. A method for setting RFID read / write power, comprising: Set the reading power level of the RFID device to the initial power level; Determine a lower limit read power level by repeatedly interrogating an RFID tag with the RFID device while reducing the read power level until The RFID tag fails to respond to the query, or The reading power level reaches a minimum power level; Determine an upper limit read power level by repeatedly interrogating the RFID tag with the RFID device while increasing the read power level until The second RFID tag responds to the interrogation, or The read power level reaches a maximum power level; and configuring the read power level of the RFID device based at least in part on the lower read power level and the upper read power level; Setting the write power level of the RFID device to the read power level; Determine the write power level as follows: repeatedly writing a coded response to the RFID tag with the RFID device to be returned when interrogated, while increasing the write power level for each subsequent write operation after the first write, and interrogating the RFID tag at the read power level by the RFID device until the RFID tag provides the coded response to the interrogation; and The write power level of the RFID device is set to the determined write power level.

2. The method of claim 1, wherein: The read power level is configured to be approximately a midpoint between the lower read power level and the upper read power level.

3. The method according to claim 1 or 2, wherein: The initial power level is based at least in part on the minimum power level and the maximum power level.

4. The method according to claim 1 or 2, wherein: The initial power level is approximately mid-point between the minimum power level and the maximum power level.

5. The method according to claim 1 or 2, wherein: The RFID device is selected from the group consisting of: an RFID reader, an RFID printer.

6. The method of claim 1 or 2, further comprising: A single RFID label is printed from a RFID label supply roll by an associated printing module.

7. The method of claim 1 or 2, further comprising: Prior to determining the upper read power level, an RFID tag is repeatedly interrogated with the RFID device while decreasing the read power level until only the RFID tag responds to the interrogation.

8. The method of claim 1 or 2, further comprising: Prior to determining the lower read power level, an RFID tag is repeatedly interrogated with the RFID device while increasing the read power level until the RFID tag responds to the interrogation for the first time.

9. The method of claim 1 or 2, further comprising: interrogating, by the RFID device, the RFID tag at the read power level; as well as A coded response based on an interrogation operation of the RFID tag is received by the RFID device only from the RFID tag.

10. An RFID read / write power setting device, comprising: a radio frequency identification (RFID) module configured to generate a radio frequency (RF) signal; a radio frequency (RF) attenuator configured to attenuate the RF signal; a radio frequency (RF) antenna configured to transmit the attenuated RF signal; as well as A controller configured to: Setting the read power level of the attenuated RF signal to an initial power level via the RF attenuator, Determine a lower limit read power level by repeatedly interrogating an RFID tag with the attenuated RF signal by the RFID module while reducing the read power level via the RF attenuator until The RFID tag fails to respond to the query, or The reading power level reaches the minimum power level, Determine an upper limit read power level by repeatedly interrogating the RFID tag with the attenuated radio frequency signal by the RFID module while increasing the read power level until The second RFID tag responds to the interrogation, or The read power level reaches a maximum power level, and configuring the read power level of the attenuated radio frequency signal based at least in part on the lower read power level and the upper read power level; Wherein, the controller is further configured to: setting the write power level of the attenuated radio frequency signal to the read power level, Determine the write power level as follows: repeatedly writing, by the RFID module, a coded response to the RFID tag to be returned when interrogated, while increasing the write power level for each subsequent write operation after the first write, and interrogating the RFID tag at the read power level by the RFID module until the RFID tag provides the coded response to the interrogation, and The write power level of the attenuated radio frequency signal is set to the determined write power level.

11. The device of claim 10, wherein: The read power level is configured to be approximately a midpoint between the lower read power level and the upper read power level.

12. The device according to claim 10 or 11, wherein: The initial power level is based at least in part on the minimum power level and the maximum power level.

13. The device according to claim 10 or 11, wherein: The initial power level is approximately mid-point between the minimum power level and the maximum power level.

14. The device of claim 10 or 11, further comprising: A printing module is configured to generate a single RFID label from a supply roll of RFID labels.

15. The device of claim 10 or 11, wherein: The antenna is an internal near field antenna.

16. The device according to claim 10 or 11, wherein: The controller is further configured to, before determining the upper read power level, repeatedly interrogate the RFID tag via the RFID module while decreasing the read power level until only the RFID tag responds to the interrogation.

17. The device according to claim 10 or 11, wherein: The controller is further configured to, before determining the lower read power level, repeatedly interrogate the RFID tag via the RFID module while increasing the read power level until the RFID tag responds to the interrogation for the first time.

18. The device according to claim 10 or 11, wherein: The radio frequency attenuator is a digital step attenuator.

19. The device according to claim 10 or 11, wherein: The radio frequency antenna is configured as an upper feed guide in a feed path between the RFID label supply roll and the print nip.

20. The device of claim 19, wherein: The RF antenna includes a plurality of tabs configured to be outside of the feed path and further configured to secure the RF antenna to an associated printhead holder.

21. The device of claim 20, wherein: The plurality of tabs are each configured to snap into a recess in the printhead holder.

22. The apparatus of claim 19, further comprising: A radio frequency shield is configured to isolate the radio frequency antenna from the RFID labels on the supply roll.

23. The device of claim 22, wherein: At least a portion of the radio frequency shield is configured to be secured to the upper feed guide.

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