Patent Description:
In such sequencing systems, fluidic systems (or subsystems) provide the flow of substances (e.g., the reagents) under the control of a control system, such as a programmed computer and appropriate interfaces.

Systems according to this invention are defined by the independent claim <NUM>. Preferred embodiments of the systems are the subject of the dependent claims.

In some implementations, a system may be provided that includes an interface to fluidically connect with a flow cell that to support analytes of interest in an analysis system, the fluidic interface including a plurality of flow paths and a plurality of effluent lines, each flow path to fluidically connect with one or more channels of the flow cell when the flow cell is mounted in the analysis system and each effluent line to fluidically connect with one of the channels of the flow cell when the flow cell is mounted in the analysis system; a selector valve fluidically connected with plurality of flow paths, the selector valve to controllably select one of the flow paths; one or more pumps, each pump fluidically connected with one or more of the effluent lines; a pressure sensor in fluidic communication with the selected flow path, the pressure sensor to detect pressure in the selected flow path and to generate pressure data based on the detected pressure; and control circuitry, the control circuity having one or more processors and a memory to store, or storing, computer-executable instructions which, when executed by the one or more processors, control the one or more processors to: control the one or more pumps so as to pressurize the selected flow path according to a prescribed test protocol; and access the pressure data and to determine whether the selected flow path maintains pressure in a desired manner.

In some implementations of the system, the fluid may include air.

In some implementations of the system, the memory may be to store, or may store, further computer-executable instructions which, when executed by the one or more processors, further control the one or more processors to cause the one or more pumps to pressurize the selected flow path in a stepwise manner, with each pressure step having a higher pressure than the previous pressure step.

In some implementations of the system, the memory may be to store, or may store, further computer-executable instructions which, when executed by the one or more processors, further control the one or more processors to cause the selector valve to successively select different flow paths of the plurality of flow paths to be pressure-tested in accordance with the prescribed test protocol.

In some implementations of the system, the plurality of flow paths may include a first flow path through one channel of the flow cell when the flow cell is mounted to the interface, and a second flow path through a second channel of the flow cell when the flow cell is mounted to the interface, in which the second flow path may be different from the first flow path.

In some implementations of the system, the plurality of flow paths may include a third flow path that includes both the first and the second flow paths.

In some implementations of the system, the selector valve may be further fluidically connected with a bypass line that bypasses the flow cell, and the memory may be to store, or may store, further computer-executable instructions which, when executed by the one or more processors, further control the one or more processors to cause the selector valve to select the bypass line to be pressure-tested in accordance with the prescribed test protocol.

The system includes a second valve that is fluidically connected with an inlet to the selector valve, in which the second valve is to seal the selected flow path at the second valve for pressure-testing of the selected flow path between the second valve and the pump.

A system in accordance with the invention provides an interface to fluidically connect with a flow cell to support analytes of interest; the fluidic interface including a plurality of flow paths and a plurality of effluent lines (<NUM>), each flow path to fluidically connect with one or more channels of the flow cell when the flow cell is mounted in the analysis system and each effluent line to fluidically connect with one of the channels of the flow cell (<NUM>) when the flow cell (<NUM>) is mounted in the analysis system, a selector valve fluidically connected with a plurality of flow paths, the selector valve to controllably select one of the flow paths, further comprising a second valve that is fluidically connected with an inlet to the selector valve; one or more pumps fluidically, each pump connected with one or more of the effluent lines, wherein the one or more pumps include one or more syringe pumps, a pressure sensor fluidically connected with the selected flow path, the pressure sensor to detect pressure in the selected flow path and to generate pressure data based on the detected pressure; and a control circuitry, the control circuity having one or more processors and a memory to store computer-executable instructions which, when executed by the one or more processors, control the one or more processors to: control the one or more pumps so as to dry the selected flow path; control the one or more pumps to pressurize the selected flow paths in accordance with the prescribed test protocol, access the pressure data, and determine whether each of the selected flow paths maintains pressure in a desired manner based on the pressure data, wherein the second valve is configured to seal the selected flow path at the second valve for pressure-testing of the selected flow path between the second valve and the pump.

In some implementations of the system, the memory may be to store, or may store, further computer-executable instructions which, when executed by the one or more processors, further control the one or more processors to cause the one or more pumps to pressurize each of the selected flow paths in a stepwise manner using a plurality of pressure steps, with each pressure step for each selected flow path having a higher pressure than the previous pressure step for that selected flow path.

In some implementations of the system, the plurality of flow paths may include a first flow path through one channel of the flow cell and a second flow path through a second channel of the flow cell, in which the second flow path may be different from the first flow path.

In some implementations of the system, the selector valve may be further fluidically connected with a bypass line that bypasses the flow cell, and the selector valve may be controllable to select the bypass line to be pressure tested in accordance with the prescribed test protocol.

For a better understanding of the invention a method is disclosed that includes implementing a stored prescribed test protocol that includes: (a) selecting a flow path from a plurality of flow paths through a flow cell in accordance with the prescribed test protocol; (b) actuating a pump to pressurize a fluid in the selected flow path; (c) generating pressure data representative of the pressure in the selected flow path; and (d) processing the pressure data representative of the pressure in the selected flow path to determine whether the selected flow path maintains pressure in a desired manner.

In some implementations of the method, actuating the pump may include actuating the pump to pressurize the selected flow path in a stepwise manner using a plurality of pressure steps.

In some implementations of the method, the method may further include repeating (a) - (d) for different flow paths through the flow cell to separately determine whether each selected flow path maintains pressure in a desired manner.

In some implementations of the method, the plurality of flow paths may include a first flow path through one channel of the flow cell and a second flow path through a second channel of the flow cell, in which the second flow path may be different from the first flow path.

In some implementations of the method, the method may further include selecting a bypass line to be pressure tested in accordance with the prescribed test protocol, actuating the pump to pressurize a fluid in the bypass line, generating pressure data representative of the pressure in the bypass line, and processing the pressure data representative of the pressure in the bypass line to determine whether the bypass line maintains pressure in a desired manner, in which the bypass line may not flow through the flow cell.

<FIG> illustrates an implementation of a sequencing system <NUM> configured to process molecular samples that may be sequenced to determine their components, the component ordering, and generally the structure of the sample. The system includes an instrument <NUM> that receives and processes a biological sample. A sample source <NUM> provides the sample <NUM> which in many cases will include a tissue sample. The sample source may include, for example, an individual or subject, such as a human, animal, microorganism, plant, or other donor (including environmental samples), or any other subject that includes organic molecules of interest, the sequence of which is to be determined. The system may be used with samples other than those taken from organisms, including synthesized molecules. In many cases, the molecules will include DNA, RNA, or other molecules having base pairs the sequence of which may define genes and variants having particular functions of ultimate interest.

The sample <NUM> is introduced into a sample/library preparation system <NUM>. This system may isolate, break, and otherwise prepare the sample for analysis. The resulting library includes the molecules of interest in lengths that facilitate the sequencing operation. The resulting library is then provided to the instrument <NUM> where the sequencing operation is performed. In practice, the library, which may sometimes be referred to as a template, is combined with reagents in an automated or semi-automated process, and then introduced to the flow cell prior to sequencing.

In the implementation illustrated in <FIG>, the instrument includes a flow cell or array <NUM> that receives the sample library. The flow cell includes one or more fluidic channels, also referred to herein as lanes, that allow for sequencing chemistry to occur, including attachment of the molecules of the library, and amplification at locations or sites that can be detected during the sequencing operation. For example, the flow cell/array <NUM> may include sequencing templates immobilized on one or more surfaces at the locations or sites. A "flow cell" may include a patterned array, such as a microarray, a nanoarray, and so forth. In practice, the locations or sites may be disposed in a regular, repeating pattern, a complex non-repeating pattern, or in a random arrangement on one or more surfaces of a support. To enable the sequencing chemistry to occur, the flow cell also allows for introduction of substances, such as including various reagents, buffers, and other reaction media, that are used for reactions, flushing, and so forth. The substances flow through the flow cell and may contact the molecules of interest at the individual sites.

In the instrument the flow cell <NUM> is mounted on a movable stage <NUM> that, in this implementation, may be moved in one or more directions as indicated by reference numeral <NUM>. The flow cell <NUM> may, for example, be provided in the form of a removable and replaceable cartridge that may interface with ports on the movable stage <NUM> or other components of the system in order to allow reagents and other fluids to be delivered to or from the flow cell <NUM>. The stage is associated with an optical detection system <NUM> that can direct radiation or light <NUM> to the flow cell during sequencing. The optical detection system may employ various methods, such as fluorescence microscopy methods, for detection of the analytes disposed at the sites of the flow cell. By way of a non-limiting example, the optical detection system <NUM> may employ confocal line scanning to produce progressive pixilated image data that can be analyzed to locate individual sites in the flow cell and to determine the type of nucleotide that was most recently attached or bound to each site. Other suitable imaging techniques may also be employed, such as techniques in which one or more points of radiation are scanned along the sample or techniques employing "step and shoot" imaging approaches. The optical detection system <NUM> and the stage <NUM> may cooperate to maintain the flow cell and detection system in a static relationship while obtaining an area image, or, as noted, the flow cell may be scanned in any suitable mode (e.g., point scanning, line scanning, "step-and-shoot" scanning).

While many different technologies may be used for imaging, or more generally for detecting the molecules at the sites, presently contemplated implementations may make use of confocal optical imaging at wavelengths that cause excitation of fluorescent tags. The tags, excited by virtue of their absorption spectrum, return fluorescent signals by virtue of their emission spectrum. The optical detection system <NUM> is configured to capture such signals, to process pixelated image data at a resolution that allows for analysis of the signal-emitting sites, and to process and store the resulting image data (or data derived from it).

In a sequencing operation, cyclic operations or processes are implemented in an automated or semi-automated fashion in which reactions are promoted, such as with single nucleotides or with oligonucleotides, followed by flushing, imaging and de-blocking in preparation for a subsequent cycle. The sample library, prepared for sequencing and immobilized on the flow cell, may undergo a number of such cycles before all useful information is extracted from the library. The optical detection system may generate image data from scans of the flow cell (and its sites) during each cycle of the sequencing operation by use of electronic detection circuits (e.g., cameras or imaging electronic circuits or chips). The resulting image data may then be analyzed to locate individual sites in the image data, and to analyze and characterize the molecules present at the sites, such as by reference to a specific color or wavelength of light (a characteristic emission spectrum of a particular fluorescent tag) that is detected at a specific location, as indicated by a group or cluster of pixels in the image data at the location. In a DNA or RNA sequencing application, for example, the four common nucleotides may be represented by distinguishable fluorescence emission spectra (wavelengths or wavelength ranges of light). Each emission spectrum, then, may be assigned a value corresponding to that nucleotide. Based upon this analysis, and tracking the cyclical values determined for each site, individual nucleotides and their orders may be determined for each site. These sequences may then be further processed to assemble longer segments including genes, chromosomes, and so forth. As used in this disclosure the terms "automated" and "semi-automated" mean that the operations are performed by system programming or configuration with little or no human interaction once the operations are initiated, or once processes including the operations are initiated.

In the illustrated implementation, reagents <NUM> are drawn or aspirated into the flow cell through valving <NUM>. The valving may access the reagents from recipients or vessels in which they are stored, such as through pipettes or sippers (not shown in <FIG>). The valving <NUM> may allow for selection of the reagents based upon a prescribed sequence of operations performed. The valving may further receive commands for directing the reagents through flow paths <NUM> into the flow cell <NUM>. Exit or effluent flow paths <NUM> direct the used reagents from the flow cell. In the illustrated implementation, a pump <NUM> serves to move the reagents through the system. The pump may also serve other useful functions, such as measuring reagents or other fluids through the system, aspirating air or other fluids, and so forth, as discussed in greater detail below. Additional valving <NUM> downstream of pump <NUM> allows for appropriately directing the used reagent to disposal vessels or recipients <NUM>.

The instrument further includes a range of circuitry that aids in commanding the operation of the various system components, monitoring their operation by feedback from sensors, collecting image data, and at least partially processing the image data. In the implementation illustrated in <FIG>, a control/supervisory system <NUM> includes a control system <NUM> and a data acquisition and analysis system <NUM>. Both systems will include one or more processors (e.g., digital processing circuits, such as microprocessors, multi-core processors, FPGA's, or any other suitable processing circuitry) and associated memory circuitry <NUM> (e.g., solid state memory devices, dynamic memory devices, on and/or off-board memory devices, and so forth) that may store machine-executable instructions for controlling, for example, one or more computers, processors, or other similar logical devices to provide certain functionality. Application-specific or general purpose computers may at least partially make up the control system and the data acquisition and analysis system. The control system may include, for example, circuitry configured (e.g., programmed) to process commands for fluidics, optics, stage control, and any other useful functions of the instrument. The data acquisition and analysis system <NUM> interfaces with the optical detection system to command movement of the optical detection system or the stage, or both, the emission of light for cyclic detection, receiving and processing of returned signals, and so forth. The instrument may also include various interfaces as indicated at reference <NUM>, such as an operator interface that permits control and monitoring of the instrument, loading of samples, launching of automated or semi-automated sequencing operations, generation of reports, and so forth. Finally, in the implementation of <FIG>, external networks or systems <NUM> maybe coupled to and cooperate with the instrument, for example, for analysis, control, monitoring, servicing, and other operations.

It may be noted that while a single flow cell and fluidics path, and a single optical detection system are illustrated in <FIG>, in some instruments more than one flow cell and fluidics path may be accommodated. For example, in a presently contemplated implementation, two such arrangements are provided to enhance sequencing and throughput. In practice, any number of flow cells and paths may be provided. These may make use of the same or different reagent receptacles, disposal receptacles, control systems, image analysis systems, and so forth. Where provided, the multiple fluidics systems may be individually controlled or controlled in a coordinated fashion. It is to be understood that the phrase "fluidically connected" may be used herein to describe connections between two or more components that place such components in fluidic communication with one another, much in the same manner that "electrically connected" may be used to describe an electrical connection between two or more components. The phrase "fluidically interposed" may be used, for example, to describe a particular ordering of components. For example, if component B is fluidically interposed between components A and C, then fluid flowing from component A to component C would flow through component B before reaching component C.

<FIG> illustrates an example fluidic system of the sequencing system of <FIG>. In the implementation illustrated, the flow cell/array <NUM> includes a series of pathways or lanes 56A and 56B which may be grouped in pairs for receiving fluid substances (e.g., reagents, buffers, reaction media) during sequencing operations. The lanes 56A are coupled to a common line <NUM> (a first common line), while the lanes 56B are coupled to a second common line <NUM>. A bypass line <NUM> is also provided to allow fluids to bypass the flow cell without entering it. As noted above, a series of vessels or recipients <NUM> allow for the storage of reagents and other fluids that may be utilized during the sequencing operation. A reagent selection valve <NUM> is mechanically coupled to a motor or actuator (not shown) to allow selection of one or more of the reagents to be introduced into the flow cell. Selected reagents are then advanced to a common line selection valve <NUM> (also referred to as a selector valve) which similarly includes a motor (not shown). The common line selection valve may be commanded (e.g., signaled, instructed) to select one or more of the common lines <NUM> and <NUM>, or both common lines, to cause the reagents <NUM> to flow to the lanes 56A and/or 56B in a controlled fashion, or the bypass line <NUM> to flow one or more of the reagents between the common line selection valve <NUM> and the pump <NUM>.

Used reagents exit the flow cell through lines (e.g., exit or effluent flow paths <NUM>) coupled between the flow cell/array <NUM> and the pump <NUM>. In the illustrated implementation, the pump includes a syringe pump having a pair of syringes <NUM> that are controlled and moved by an actuator <NUM> to aspirate the reagents and other fluids and to expel the reagents and fluids during different operations of the testing, verification and sequencing cycles. The pump assembly may include various other parts and components, including valving, instrumentation, actuators, and so forth (not shown). In the illustrated implementation, pressure sensors 74A and 74B sense pressure on inlet lines of the pump, while a pressure sensor 74C is provided to sense pressures output by the syringe pump.

Fluids used by the system enter a used reagent selection valve <NUM> from the pump. This valve allows for selection of one of multiple flow paths for used reagents and other fluids. In the illustrated implementation, a first flow path leads to a first used reagent receptacle <NUM>, while a second flow path leads through a flow meter <NUM> a second used reagent receptacle <NUM>. Depending upon the reagents used, it may be advantageous to collect the reagents, or certain of the reagents in separate vessels for disposal, and the used reagent selection valve <NUM> allows for such control.

It should be noted that valving within the pump assembly may allow for various fluids, including reagents, solvents, cleaners, air, and so forth to be aspirated by the pump and injected or circulated through one or more of the common lines, the bypass line, and the flow cell. Moreover, as noted above, in a presently contemplated implementation, two parallel implementations of the fluidics system shown in <FIG> are provided under common control. Each of the fluidics systems may be part of a single sequencing instrument, and may carry out functions including sequencing operations on different flow cells and sample libraries in parallel.

The fluidics system operates under the command of control system <NUM> which implements prescribed protocols for testing, verification, sequencing, and so forth. The prescribed protocols will be established in advance and include a series of events or operations for activities such as aspirating reagents, aspirating air, aspirating other fluids, expelling such reagents, air and fluids, and so forth. The protocols will allow for coordination of such fluidic operations with other operations of the instrument, such as reactions occurring in the flow cell, imaging of the flow cell and its sites, and so forth. In the illustrated implementation, the control system <NUM> employs one or more valve interfaces <NUM> which are configured to provide command signals for the valves, as well as a pump interface <NUM> configured to command operation of the pump actuator. Various input/output circuits <NUM> may also be provided for receiving feedback and processing such feedback, such as from the pressure sensors 74A-C and flow meter <NUM>.

<FIG> illustrates certain of the functional components of the control/supervisory system <NUM>. As illustrated, the memory circuitry <NUM> stores prescribed routines that are executed during testing, commissioning, troubleshooting, servicing, and sequencing operations. Many such protocols and routines may be implemented and stored in the memory circuitry, and these may be updated or altered from time to time. As illustrated in <FIG>, these may include a fluidics control protocol <NUM> for controlling the various valves, pumps, and any other fluidics actuators, as well as for receiving and processing feedback from fluidics sensors, such as valves, and flow and pressure sensors. A stage control protocol <NUM> allows for moving the flow cell as desired, such as during imaging. An optics control protocol <NUM> allows for commands to be issued to the imaging components to illuminate portions of the flow cell and to receive returned signals for processing. An image acquisition and processing protocol <NUM> allows for the image data to be at least partially processed for extraction of useful data for sequencing. Other protocols and routines may be provided in the same or different memory circuitry as indicated by reference <NUM>. In practice, the memory circuitry may be provided as one or more memory devices, such as both volatile and non-volatile memories. This memory may be within the instrument, and some may be off-board.

One or more processors <NUM> access the stored protocols and implement them on the instrument. As noted above, the processing circuitry may be part of application-specific computers, general-purpose computers, or any suitable hardware, firmware and software platform. The processors and the operation of the instrument may be commanded by human operators via an operator interface <NUM>. The operator interface may allow for testing, commissioning, troubleshooting, and servicing, as well as for reporting any issues that may arise in the instrument. The operator interface may also allow for launching and monitoring sequencing operations.

The fluidics control protocol <NUM> stored in the memory <NUM> may also include diagnostic routines that can be executed by the processor <NUM> to evaluate the integrity and reliability of the fluidic system. With this in mind, present implementations are directed toward methods of operating the fluidics system of the instrument <NUM> to isolate and test various flow paths (e.g., flow cell channels, common lines, and pump lines) of the fluidic system for potential leaks using pressurized air to determine whether each of the flow paths maintains pressure in a desired manner. Using these diagnostic routines, an operator may evaluate the fluidic system routinely (e.g., before each use of the instrument, at the beginning of each day or shift, on weekly or monthly intervals) or at will, based on a particular concern. Accordingly, present implementations enable the early detection and diagnosis of potential fluid leaks. As such, the presently disclosed diagnostic routines can help to avoid sample loss, data loss, and damage to sensitive components of the instrument <NUM>, which can result from a fluid leak during operation of the instrument <NUM>.

<FIG> illustrates a portion of the fluidic system <NUM> for an implementation of the instrument <NUM>, wherein the arrows are indicative of the flow of substances (e.g., reagents, buffers, analytes) through the various illustrated flow paths during sample analysis. For the implementation illustrated in <FIG>, a flow cell array <NUM> includes two lane pairs, denoted as lane pair A and lane pair B. Each of the two lane pairs includes two respective fluidic channels or lanes, denoted as lanes L1, L2, L3, and L4 in <FIG>. For the illustrated implementation, the flow cell array <NUM> is designed to be operated as illustrated in <FIG>, with both lane pairs A and B present in the flow cell <NUM>, or with a single lane pair (e.g., lane pairs A or B) present in the flow cell <NUM>, as discussed in greater detail below with respect to <FIG>. Further, the fluidic system <NUM> illustrated in <FIG> includes a number of inline pressure sensors <NUM> (e.g., pressure sensors 122A-122E, pressure sensors 74A-C of <FIG>) that are respectively coupled the effluent lines 36A, 36B, 36C, and 36D and the bypass line <NUM>. These inline pressure sensors <NUM> are communicatively coupled (e.g., via a wired or wireless communication channel) to the processor <NUM> of the control system <NUM> and configured to output electronic signals to the processor <NUM> corresponding to the pressure of fluids in the various flow paths of the fluidic system <NUM>.

Additionally, the pump <NUM> of the fluidic system illustrated in <FIG> includes multiple syringe pumps <NUM> (e.g., syringe pumps 124A and 124B). As illustrated, the syringe pumps <NUM> each include one or more respective syringes <NUM> (e.g., syringes 126A and 126B) that are respectively actuated by actuators <NUM> (e.g., actuators 128A and 128B). The illustrated syringe pumps <NUM> also include valving <NUM> (e.g., valving 130A and 130B), which enable the syringe pumps to push or pull fluids into and out of different orifices or ports of the pumps <NUM>. For example, <FIG> are diagrams illustrating flow paths through the valving <NUM> (e.g., valving 130A and 130B) of <FIG> in different positions. As illustrated, the valving <NUM> includes two valve units 132A and 132B (e.g., solenoid valves or other controllable valves) that, as the syringe <NUM> is actuated, cooperate to aspirate a volume of fluids or dispense a volume of fluid into a flow cell port <NUM> leading to the flow cell array <NUM>, a used reagent port <NUM> leading to the used reagent collection system, or a bypass port <NUM> leading to the bypass line <NUM>. In <FIG>, referred to hereafter as the "I" position, the valve units 132A and 132B enable the syringe <NUM> to draw fluid from, or introduce fluid into, the flow cell port <NUM>. In <FIG>, referred to hereafter as the "O" position, the valve units 132A and 132B enable the syringe <NUM> to draw fluid from or introduce fluid into, the used reagent port <NUM>. In <FIG>, referred to hereafter as the "B" position, the valve units 132A and 132B enable the syringe <NUM> draw fluid from or introduce fluid into the bypass port <NUM>. As generally discussed above, the control system <NUM> sends control signals to control the actuation of the actuators <NUM> and the valving <NUM>. In certain implementations, the syringe pumps <NUM>, including the associated valving, may be rated for pressures up to about <NUM> bar (<NUM> pounds per square inch gauge (psig)); however, in other implementations, other pressures may be used in accordance with the present disclosure.

The common line selection valve <NUM> of the implementation illustrated in <FIG> enables fluid coupling of a reagent flow path <NUM> (disposed between the reagent selector valve (RSV) <NUM> and the common line selection valve <NUM>), the first common line <NUM>, the second common line <NUM>, the bypass line <NUM>, and an air inlet <NUM>, in various manners. For example, <FIG> illustrate a cross-sectional diagrammatical view of the implementation of the common line selection valve <NUM> illustrated in <FIG> in various positions or orientations. Different shading or hashing is used to distinguish between the ports <NUM> of the common line selection valve <NUM>, which include: a bypass port 150A that is fluidically coupled to the bypass line <NUM>, an air port 150B that is fluidically coupled to the air inlet <NUM>, a lane pair A port 150C that is fluidically coupled to the first common line <NUM> leading to lane pair A, an RSV port 150D that is fluidically coupled to the reagent selector valve <NUM> via the reagent flow path <NUM>, and a lane pair B port 150E that is fluidically coupled to the second common line <NUM> leading to lane pair B.

The common line selection valve <NUM> illustrated in <FIG> has a rounded, central portion <NUM> that rotates about a central point <NUM> and that includes various channels <NUM>. The central portion <NUM> is firmly sealed against ports <NUM> such that fluid does not leave a port <NUM> unless a channel <NUM> is suitably aligned to enable flow to another port <NUM>. For example, the orientation of the common line selection valve <NUM> illustrated in <FIG>, referred to hereafter as the "RSV to Lane Pair A" position, fluidically couples the RSV port 150D to the bypass port 150A. The orientation illustrated in <FIG>, referred to hereafter as the "RSV to Lane Pair B" position, fluidically couples the RSV port 150D to the lane pair B port 150E. The orientation illustrated in <FIG>, referred to hereafter as the "RSV to Lane Pairs A & B" position, fluidically couples the RSV port 150D to the to both the lane pair A port 150C and the lane pair B port 150E. As such, the orientations illustrated in <FIG> enable the implementation of the fluidic system <NUM> illustrated in <FIG> to operate, as described above, to direct fluids received from the reagent selection valve <NUM> through a single lane pair (e.g., lane pairs A or B) or both lane pairs A and B simultaneously.

The orientations of the common line selection valve <NUM> illustrated in <FIG>, as well as other potential positions, may also be useful for diagnostic purposes to enable the processor <NUM> to isolate, prepare, and pressure test the various flow paths of the fluidic system. In particular, the orientation illustrated in <FIG>, referred to hereafter as the "Air to Lane Pairs A & B" position, fluidically couples the air port 150B to both lane pair A port 150C and lane pair B port 150E, which is useful to dry the flow cell <NUM> prior to pressure testing, as discussed below. The orientation illustrated in <FIG>, referred to hereafter as the "Air to Bypass" position, fluidically couples air port 150B to the bypass port 150A, which is useful to enable air to be introduced into the fluidic system during certain pressure tests, as discussed below. The orientation illustrated in <FIG>, referred to hereafter as the "RSV to Bypass" position, fluidically couples the RSV port 150D to the bypass port 150A, which is useful during pressure testing of the bypass line <NUM>, as discussed below.

As mentioned, the fluidics control protocol <NUM> stored in the memory <NUM> may include diagnostic routines that can be executed by the processor <NUM> to evaluate the fluidic system <NUM> for potential leaks. <FIG> is a flow diagram representing an implementation of a process <NUM> for pressure testing the fluidic system <NUM> of the instrument <NUM> illustrated in <FIG>. The illustrated process <NUM> begins with preparing system for pressure testing of a particular flow path (block <NUM>). While discussed in detail below with respect to <FIG>, in block <NUM>, processor <NUM> may isolate and prepare the particular flow path of the fluidic system <NUM>, as well as otherwise ensure that the instrument <NUM> is ready to begin pressure testing. Once preparation is successfully completed, the processor <NUM> may perform pressure testing to determine a leak rate of the particular flow path (block <NUM>). While discussed in detail below with respect to <FIG>, in block <NUM>, processor <NUM> may pressurize the particular flow path of the fluidic system <NUM> to a target pressure, measure a change in pressure over a known period of time, and determine a leak rate based on the measured change in pressure.

Continuing through the process <NUM> illustrated in <FIG>, the processor <NUM> may then determine whether the leak rate is less than or equal to a predetermined threshold value (block <NUM>). If the determined leak rate is greater than the predetermined threshold value, the processor <NUM> may terminate further pressure testing and record details regarding the failure (block <NUM>). In certain implementations, the predetermined threshold value for the leak rate may be calculated based, at least in part, on the volume of the particular flow path being tested and the viscosity of the fluids that traverse the fluidic system during operation (e.g., reagents, buffers, analytes) relative to the viscosity of air. For example, if a leak rate of the fluids that traverse the fluidic system during operation should be maintained at or below approximately <NUM> microliters per minute (µL/min) for a four-lane configuration of the fluidic system <NUM>, as illustrated in <FIG>, based on the difference between the viscosity of the fluids that traverse the fluidic system during operation (e.g., reagents, buffers, analytes) and air, the predetermined threshold value may be approximately <NUM> Pa/s (<NUM> pounds per square inch per second (psi/sec)). By further example, if a leak rate of the fluids that traverse the fluidic system during operation should be maintained at or below approximately <NUM> microliters per minute (µL/min) for a two-lane configuration with only one lane pair A or B loaded (approximately half the volume of the four-lane configuration), based on the viscosity difference, the predetermined threshold value may again be approximately <NUM> Pa/s (<NUM> psi/sec).

If the determined leak rate is less than or equal to the predetermined threshold value, the processor <NUM> may determine whether additional pressure tests of other flow paths should be performed (block <NUM>). If no further pressure testing is to be performed, then the processor <NUM> may terminate pressure testing and record details regarding the successful pressure testing (block <NUM>). If additional pressure testing is to be performed, the processor <NUM> may select the next flow path to be tested (block <NUM>), and then the actions set forth in blocks <NUM>, <NUM>, <NUM>, and <NUM> may be repeated, as indicated by the arrow <NUM>. In certain implementations, the processor <NUM> may prompt the operator to perform one or more physical operations (e.g., load a lane pair, remove a lane pair, remove/load multiple lane pairs, e.g., where multiple lane pairs are in a single flow cell cartridge) to enable a particular flow path to be tested.

<FIG> is a flow diagram illustrating an implementation of a process <NUM> for preparing the fluidic system <NUM> for pressure testing, corresponding to block <NUM> of <FIG>. The illustrated process <NUM> begins with sending control signals and/or receiving sensor data to verify the state of the system (block <NUM>). This may include, for example, ensuring that the appropriate number of lane pairs are present in the flow cell <NUM>. In certain implementations, as illustrated, the process <NUM> may include the processor <NUM> sending control signals to the fluidic system <NUM> to dry the system before pressure testing (block <NUM>). For example, as mentioned above with respect to <FIG>, the processor <NUM> may provide appropriate control signals to orient the common line selection valve <NUM> in the "Air to Lane Pairs A & B" position and the reagent selection valve <NUM> in a blocked or closed position, while actuating the pump <NUM> to draw and remove liquid from the flow paths of the fluidic system, thereby drawing air into the system through the air inlet <NUM>.

The process <NUM> illustrated in <FIG> continues with the processor <NUM> receiving baseline data from sensors on an isolated flow path for sensor calibration (block <NUM>). For example, unless already in the correct position, the processor <NUM> may first provide suitable control signals to the common line selection valve <NUM> to fluidically couple the flow path to be pressure tested, or the entire fluidic system <NUM>, to the air inlet <NUM> and equalize the pressure in the flow path with ambient atmospheric pressure. For example, the common line selection valve <NUM> may be disposed in the "Air to Lane Pairs A & B" position, illustrated in <FIG>, when the flow path to be tested includes a lane pair, and may be disposed in the "Air to Bypass" position, illustrated in <FIG>, when the flow path to be tested includes the bypass line <NUM>. After fluidically coupling the flow path to be pressure tested to the air inlet, one or more pressure sensors 122A-122E of the fluidic system <NUM>, as illustrated in <FIG>, may be used to measure a baseline pressure (e.g., ambient pressure) for calibration.

Returning to <FIG>, the illustrated process <NUM> concludes with the processor <NUM> sending control signals to appropriately orient the common line selection valve <NUM> and/or the reagent selection valve <NUM> to isolate the flow path to be pressure tested (block <NUM>). As discussed above with respect to <FIG>, the common line selection valve <NUM> may be oriented in a number of different positions to selectively fluidically couple, and selectively isolate, the various flow paths of the fluidic system <NUM>. The isolation set forth in block <NUM> is discussed in further detail below with respect to <FIG>.

<FIG> is a flow diagram illustrating an implementation of a process <NUM> for performing pressure testing to determine a leak rate of the particular flow path of the fluidic system <NUM>, corresponding to block <NUM> of <FIG>. The illustrated process <NUM> begins with the processor <NUM> sending control signals to actuate one or more portions of the pump <NUM> (e.g., valving <NUM> and/or syringes <NUM> of at least one of the syringe pumps <NUM>) to pressurize the flow path being pressure tested with air to a predetermined target pressure (block <NUM>). It may be appreciated that the target pressure may correspond to a pressure that the fluidic system <NUM> experiences during normal operation, or may correspond to a pressure that is greater than (e.g., two times, three times, etc.) the pressure that the fluidic system <NUM> experiences during normal operation. For example, in an implementation, if the fluidic system <NUM> experiences approximately <NUM> bar (<NUM> psig) of pressure during sample analysis, then, in certain implementations, the target pressure for pressure testing may be approximately <NUM> bar (<NUM> psig) to provide a more intensive pressure test of the flow path.

As discussed in greater detail below, for pressure testing different configurations of the fluidic system <NUM>, a particular syringe pump <NUM> (e.g., syringe pump 124A or 124B) may be used to pressurize the flow path. In other implementations, both syringe pumps may cooperate to pressurize the flow path being tested. Additionally, the processor <NUM> may determine the current pressure within the flow path based on pressure measurements received from pressure sensors <NUM>. In cases in which the flow path being pressure tested includes multiple pressure sensors <NUM>, the processor <NUM> may use pressure measurements from a particular pressure sensor, for example, to compare the measurements from multiple pressure sensors to verify operation of the pressure sensors.

Further, while other implementations may include a different pumping mechanism, the syringe pumps <NUM> of the implementation of the fluidic system <NUM> illustrated in <FIG> generally increase the pressure in the flow path being tested in discrete pressure steps. For example, <FIG> is a graph <NUM> illustrating pressure (<NUM> PA/<NUM> psi) for lanes L1-L4 as respectively measured by the pressure sensors 122A-122D in a flow path of the fluidic system <NUM> of the instrument <NUM> as a function of time (sec) during the pressure testing described by the method <NUM> of <FIG>. The pressurization set forth in block <NUM> of <FIG> is denoted by the pre-measurement region <NUM> of the graph <NUM> of <FIG>. More specifically, the region <NUM> includes repeated cycles during which, first, pressure in the flow path is relatively constant as air is aspirated into the syringe <NUM> from the atmosphere, as indicated in the region <NUM>. The valving is then actuated to cause the syringe <NUM> to be fluidically connected with the flow path. Then, pressure in the flow path equilibrates as pressurized air in the flow path mixes with lower-pressure air in the syringe, as indicated in the region <NUM>. Subsequently, pressure in the flow path increases as air from the syringe is dispensed into the flow path, as indicated in the region <NUM>. This repeated pattern results in the curves <NUM> of the graph <NUM> demonstrating pressure steps <NUM>. It may be appreciated that, if the processor <NUM> determines that the fluidic system is not able to be pressurized to the target pressure, then the pressure test may be terminated with a failure indication.

Turning briefly back to <FIG>, in certain implementations, the processor <NUM> may wait a predetermined amount of time to allow pressure to equilibrate (block <NUM>) before proceeding with the process <NUM>. As shown by the graph <NUM> of <FIG>, while the curves <NUM> representing the pressures of the lanes L1-L4 closely trace one another and are not well-resolved, the curves differ from one another most during (and briefly after) the opening of the valving <NUM> of the syringe pump <NUM> (e.g., during the region <NUM>). In certain implementations, rather than wait a predetermined amount of time, the processor <NUM> instead may wait until the pressure measurements received from each of the lanes L1-L4 are the same, within an acceptable tolerance.

Proceeding through the process <NUM> illustrated in <FIG>, the processor <NUM> receives measurement data from at least one of the pressure sensors <NUM> positioned along the selected flow path to determine a first pressure (block <NUM>). The processor <NUM> then waits a predetermined amount of time to allow the pressure to decay (block <NUM>) before receiving measurement data from at least one of the sensors on selected flow path to determine a second pressure (block <NUM>). Returning to <FIG>, the measurement region <NUM> is indicated on the graph <NUM> and includes the actions set forth in blocks <NUM>, <NUM>, and <NUM> of <FIG>. As illustrated, the first pressure measurement is collected (indicated by the arrow <NUM>), and after a predetermined amount of time passes (measurement or decay time, indicated by the region <NUM>), the second pressure measurement is collected (indicated by the arrow <NUM>). For example, the predetermined amount of time should be sufficiently long to enable the detection of a leak rate greater than a predetermined threshold (e.g., approximately <NUM> PA/s (<NUM> psi/sec) at approximately <NUM> bar (<NUM> psig)), in accordance with the speed and resolution of the pressure sensors <NUM> of the fluidic system <NUM>. In other implementations, any suitable number of pressure measurements may be collected by the processor <NUM> from any suitable number of pressure sensors <NUM> to determine the leak rate.

As illustrated in <FIG>, after collecting the second pressure measurement, the processor <NUM> continues through the process <NUM> by sending control signals to move the common line selection valve <NUM>, actuate valving <NUM> and/or syringes <NUM> of at least one of the syringe pumps <NUM> to evacuate the pressurized air from the flow path (block <NUM>). This corresponds to the post-measurement region <NUM> indicated in the graph <NUM> of <FIG>. More specifically, the post-measurement region <NUM> includes repeated cycles with time periods <NUM> during which pressure decreases as air from the flow path is aspirated into the syringe, followed by time periods <NUM> when pressure in the flow path is relatively constant as air is aspirated from the syringe <NUM> and into the atmosphere after the syringe input/output is switched from the flow path to the air inlet, for example. The process <NUM> illustrated in <FIG> concludes with the processor <NUM> calculating leak rate based on the first and second pressure measurements (block <NUM>). For example, the processor <NUM> may calculate the leak rate by dividing the difference between the first and second pressure measurements by the measurement time.

As mentioned above with respect to block <NUM> of <FIG>, the processor <NUM> is capable of sending control signals to suitably orient the common line selection valve <NUM> and/or the reagent selection valve <NUM> to isolate the flow path to be pressure tested. <FIG> are diagrammatical overviews of particular isolated flow paths of the implementation of the fluidic system <NUM> of <FIG> undergoing pressure testing in different configurations. In the figures, the components of the flow path being pressure tested are bolded or highlighted.

<FIG> indicates an example of a flow path <NUM> of the fluidic system <NUM> that can be pressure tested when both lane pairs A and B are present in the flow cell <NUM>. The illustrated flow path <NUM> includes the first and second common line <NUM> and <NUM>, the lanes L1, L2, L3 and L4 of lane pairs A and B, the effluent lines 36A-D, and the syringe pumps <NUM>. As illustrated, reagent selection valve <NUM> is in a closed or blocked position, the common line selection valve <NUM> is in the RSV to Lane Pairs A & B position illustrated in <FIG>, and the valving 130A of the syringe pump 124A is in a closed or blocked position. Furthermore, the valving 130B of the syringe pump 124B is in the B position, and the actuator 128B and the valving 130B are suitably actuated to aspirate air through the bypass port <NUM> and then dispense the air through the lane pair port <NUM>, as discussed above with respect to <FIG>. The common line selector valve <NUM> may be actuated, in tandem, to switch between fluidically connecting the bypass line <NUM>/bypass port <NUM> with the air inlet <NUM> (for air aspiration) and fluidically connecting the lane pairs A/B with the reagent flow path <NUM> (for pressure testing). Alternatively, the bypass port of the valving 130B may instead not be fluidically connected with the bypass line, but may simply connect with ambient air, allowing air to be aspirated directly into the syringe pump 124B without needing to use the bypass line <NUM> or actuate the common line selector valve <NUM>. Accordingly, the entire flow path indicated in <FIG> can be pressure tested in the manner set forth above.

<FIG> indicates an example of a flow path <NUM> of the fluidic system <NUM> that can be pressure tested when only lane pair A is present or loaded into the flow cell array <NUM>. The illustrated flow path <NUM> includes the first common line <NUM>, the lanes L1 and L2 of lane pair A, effluent lines 36A and 36B, and syringe pump 124A. As illustrated, the common line selection valve <NUM> is in the Air to Bypass position illustrated in <FIG>. Furthermore, the valving 130A of the syringe pump 124A is in the B position, and the actuator 128A is suitably actuated to aspirate air through the bypass port <NUM> and then dispense the air through the flow cell port <NUM> after the valving 130A is actuated to connect with the effluent lines 36A and 36B, as discussed above with respect to <FIG>. Accordingly, the entire flow path <NUM> indicated in <FIG> can be pressure tested in the manner set forth above.

<FIG> indicates an example of a flow path <NUM> of the fluidic system <NUM> that can be pressure tested when only lane pair B is present or loaded into the flow cell array <NUM>. The illustrated flow path <NUM> includes the reagent flow path <NUM>, the second common line <NUM>, the lanes L3 and L4 of lane pair B, effluent lines 36C and 36D, and syringe pump 124B. As illustrated, the reagent selection valve <NUM> is in a closed or blocked position, the common line selection valve <NUM> is in the RSV to Lane Pair B position illustrated in <FIG>. Furthermore, the valving 130B of the syringe pump 124B is in the B position, and the actuator 128B is suitably actuated to aspirate air through the bypass port <NUM> and dispense the air through the flow cell port <NUM> when the valve 130B is then actuated to the I position (see <FIG>). The common line selector valve <NUM> may be actuated, in tandem, to switch between fluidically connecting the bypass line <NUM>/bypass port <NUM> with the air inlet <NUM> (for air aspiration) and fluidically connecting lane pair B with the reagent flow path <NUM> (for pressure testing). Alternatively, in some implementations, the valving 130B may have a bypass port that simply opens onto ambient air and is not fluidically connected with the bypass line <NUM>, thereby allowing air to be aspirated directly into the syringe pump 124B through the bypass port without traveling through the bypass line and without activation of the common line selector valve <NUM>. Accordingly, the entire flow path <NUM> indicated in <FIG> can be pressure tested as set forth above.

<FIG> indicates an example of a flow path <NUM> of the fluidic system <NUM> that can be pressure tested when no lane pairs are loaded into the flow cell array <NUM>. The illustrated flow path <NUM> includes the bypass line <NUM>, the reagent flow path <NUM>, and syringe pump 124A. As illustrated, the reagent selection valve <NUM> is in a closed or blocked position, the common line selection valve <NUM> is in the RSV to Bypass position illustrated in <FIG>. Furthermore, the valving 130A of the syringe pump 124A is in the B position, and the actuator 128A is suitably actuated to aspirate air through the flow cell port <NUM> and dispense the air through the bypass port <NUM>. The common line selector valve <NUM> may be actuated, in tandem, to switch between fluidically connecting the bypass line <NUM>/bypass port <NUM> with the air inlet <NUM> (for air aspiration) and fluidically connecting the bypass line <NUM> with the reagent flow path <NUM> (for pressure testing). Accordingly, the entire flow path <NUM> indicated in <FIG> can be pressure tested in the manner described above. It is to be understood that in the above examples, the same tests may be run even if one or both of the flow lane sets that are described as not being present actually are present. For example, if both sets of flow lanes are present, each set may be individually pressure tested. This may, for example, be of use when there is a leak detected-individual flow lane tests may be run to try and narrow down where the leak is. It is also to be understood that different segments of the flow paths may be tested in other combinations, e.g., the flow path <NUM> may be added or omitted from any of the flow paths in any of the above pressure tests. It is to be further understood that the flow paths used (and the valving actuated in order to establish such flow paths) in order to aspirate air into the pumps for pressure testing may vary from what is discussed above-in implementations where multiple pumping cycles are needed to adequately pressurize the selected flow paths, any combination of flow paths may be used to convey air to the pumps for pressurization of the tested flow path, as long as the flow path(s) used for air aspiration is kept fluidically isolated from the flow path being tested.

It may be appreciated that pressurization of the flow path of the fluidic system <NUM> for pressure testing, as set forth in block <NUM> of <FIG>, could reasonably be implemented using proportional pressure control mechanisms. However, it is presently recognized that proportional control can fail to be sufficiently robust to deal with the substantial differences between the volumes of the various flow paths of the fluidic system <NUM> that may be pressure tested, resulting in pressure test runs that fail to reach the target pressure and/or in which the pressure over-corrects and oscillates around the target pressure. As such, in certain implementations, the pressurization set forth in block <NUM> may be implemented using a proportional-integral-derivative controller (PID controller). For example, in certain implementations, effective pressure control for the disclosed pressure testing may incorporate the use of a robust system control method and a PID controller (e.g., integrated into or communicatively coupled to the processor <NUM>) to achieve the target testing pressure in the flow path being tested. It is presently recognized that this configuration improves the ability of the fluidic system <NUM> to efficiently reach the target pressure while avoiding unnecessary pressure oscillations and pressure instabilities despite significant differences in the volumes of different flow paths of the fluidic system <NUM> that may be pressure tested.

By specific example, in an implementation, the pressurization of block <NUM> in <FIG> may be implemented to suitably pressurize a flow path to a target pressure for leak testing, as presently disclosed. <FIG> is a flow diagram illustrating an implementation of a system control method <NUM> at least partially executable by a PID (e.g., part of processing circuitry <NUM>) to perform the actions set forth in block <NUM> of <FIG>. The illustrated method <NUM> begins with the processor <NUM> receiving (block <NUM>) a first measurement from one or more pressure sensors 122A-122E disposed along the flow path being pressure tested. Subsequently, the processor <NUM> may send (block <NUM>) control signals to suitably actuate the valving <NUM> and the actuator <NUM> of a syringe pump <NUM> to cause the syringe pump <NUM> to perform a single cycle or stroke to pressurize the flow path. The illustrated method <NUM> continues with the processor <NUM> receiving (block <NUM>) a second measurement from one or more pressure sensors 122A-122E disposed along the flow path being pressure tested. Using the first and second measurements, the processor <NUM> may calculate (block <NUM>) a change in pressure per stroke of the syringe pump <NUM>.

The method <NUM> continues with the processor <NUM> calculating the PE (pressure error) (block <NUM>), which is a value that is indicative of how aggressively the gap between the current pressure and the target pressure should be closed. In certain implementations, PE may be calculated according to equation <NUM>: <MAT>.

in which the values of GainP, GainI, and GainD are specific to the configuration of the fluidic system <NUM>. For example, in certain implementations, GainP is approximately <NUM>, GainI is approximately <NUM>, and GainD is approximately <NUM>; however, in other implementations, different values may be used. In the present context, the term "approximately" is intended to mean that the values indicated are not exact and the actual value may vary from those indicated (e.g., ±<NUM>%, ±<NUM>%, ±<NUM>%, or ±<NUM>%) in a manner that does not materially alter the operation concerned. In certain implementations, the GainP may be set to a small value to avoid overshooting the target pressure, while the GainI and GainD values are tuned to incrementally close in on the target pressure.

In certain implementations, the error, integral, and derivative values may be respectively calculated via the PID according to equations <NUM>, <NUM>, and <NUM>:<MAT><MAT> <MAT>
where integralprevious is the previously calculated integral value, errorprevious is the previously calculated error value, and Δt is the time interval between error calculations (the "previous" values may initially be set to zero when the pressurization routine first begins). As indicated by block <NUM>, a positive PE value may indicate that the pressure should be increased (block <NUM>) to reach the target pressure, while a negative PE value may indicate that the pressure should be decreased (block <NUM>) to reach the target pressure. However, before increasing or decreasing the pressure in the flow path, the processor <NUM> first determines whether the PE value is within a predetermined tolerance value (e.g., ±<NUM> bar ( ±<NUM> psig)) of the target pressure. For example, as indicated in block <NUM>, if processor <NUM> determines that the positive PE value not greater than the predetermined tolerance value, then the processor <NUM> may proceed to block <NUM> of the pressure testing method <NUM> illustrated in <FIG>. Similarly, as indicated in block <NUM>, if processor <NUM> determines that the negative PE value is greater than the negative predetermined tolerance value, then the processor <NUM> may also proceed to block <NUM>.

If the processor <NUM> determines in block <NUM> that the positive PE value is greater than the predetermined tolerance value (e.g., <NUM> bar (<NUM> psig)), then the processor <NUM> may provide suitable control signals to the syringe pump <NUM> to decrease the pressure in the flow path (block <NUM>). Similarly, if the processor <NUM> determines in block <NUM> that the negative PE value is less than the negative predetermined tolerance value (e.g., -<NUM> bar (-<NUM> psig)), then the processor <NUM> may provide suitable control signals to the syringe pump <NUM> to increase the pressure in the flow path (block <NUM>). In both situations, the processor <NUM> may send control signals to actuate the valving <NUM> to enable the syringe pump <NUM> to aspirate air from a particular port (e.g., the flow cell port <NUM> or the bypass port <NUM>), and again actuate the valving <NUM> to enable the syringe pump <NUM> to dispense the air into another particular port (e.g., the flow cell port <NUM> or the bypass port <NUM>) to suitably increase or decrease the pressure in the flow path, as discussed above. Depending on the PE value, the processor <NUM> may utilize full strokes of the syringe pump <NUM> or may calculate a pump position that is less than a full stroke to reach the target pressure. For example, in certain implementations, the processor <NUM> may calculate the pump position according to equation <NUM>: <MAT>.

After actuating the syringe pump <NUM> to increase or decrease the pressure in the flow path, the method <NUM> continues with the processor <NUM> receiving another measurement from one or more pressure sensors 130A-E (block <NUM>). Subsequently, the processor <NUM> may determine whether the number of cycles of the syringe pump <NUM> during the pressurization method <NUM> has exceeded a predetermined threshold value (e.g., <NUM> cycles) (block <NUM>), and, if so, may terminate pressure testing with a failure indication (block <NUM>). If, however, the processor <NUM> determines that the cycle limit has not yet been reached, then the processor may proceed back to block <NUM>, as indicated by the arrow <NUM>, and calculate PE once more based on the latest pressure measurement.

The use, if any, of ordinal indicators, e.g., (a), (b), (c). or the like, in this disclosure and claims is to be understood as not conveying any particular order or sequence, except to the extent that such an order or sequence is explicitly indicated. For example, if there are three steps labeled (i), (ii), and (iii), it is to be understood that these steps may be performed in any order (or even concurrently, if not otherwise contraindicated) unless indicated otherwise. For example, if step (ii) involves the handling of an element that is created in step (i), then step (ii) may be viewed as happening at some point after step (i). Similarly, if step (i) involves the handling of an element that is created in step (ii), the reverse is to be understood.

It is also to be understood that the use of "to," e.g., "a valve to switch between two flow paths," may be replaceable with language such as "configured to," e.g., "a valve configured to switch between two flow paths", or the like.

Claim 1:
A system comprising:
an interface to fluidically connect with a flow cell (<NUM>) to support analytes of interest in an analysis system, the fluidic interface including a plurality of flow paths and a plurality of effluent lines (<NUM>), each flow path to fluidically connect with one or more channels of the flow cell when the flow cell is mounted in the analysis system and each effluent line to fluidically connect with one of the channels of the flow cell when the flow cell (<NUM>) is mounted in the analysis system;
a selector valve (<NUM>) fluidically connected with plurality of flow paths, the selector valve (<NUM>) to controllably select one of the flow paths;
one or more pumps (<NUM>), each pump fluidically connected with one or more of the effluent lines (<NUM>); wherein the one or more pumps comprises one or more syringe pumps (<NUM>, <NUM>);
characterised in that the system further comprises a second valve (<NUM>) or a reagent selector valve (<NUM>) that is fluidically connected with an inlet to the selector valve (<NUM>), and
a pressure sensor (<NUM>) in fluidic communication with the selected flow path, the pressure sensor (<NUM>) to detect pressure in the selected flow path and to generate pressure data based on the detected pressure; and
a control circuitry, the control circuity having one or more processors (<NUM>) and a memory (<NUM>) to store computer-executable instructions which, when executed by the one or more processors (<NUM>), control the one or more processors (<NUM>) to:
cause the selector valve (<NUM>) to successively select different flow paths of the plurality of flow paths to be pressure-tested in accordance with a prescribed test protocol; wherein the second valve (<NUM>) or the reagent selector valve (<NUM>) is configured to seal the selected flow path at the second valve (<NUM>) for pressure-testing of the selected flow path between the second valve (<NUM>) or the reagent selector valve (<NUM>) and the pump (<NUM>),
control the one or more pumps (<NUM>) so as to pressurize the selected flow path according to the prescribed test protocol; and
access the pressure data and to determine whether the selected flow path or each of the selected flow paths maintains pressure in a desired manner.