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Sequence reads in balloon order, capture TIR per channel, and stop reading order from being an operator variable.
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Customer gage standards are specific about how a checking fixture gets built. They specify net locators and clamp sequence, hardened SPC bushings and their bore sizes, indicator mounting and shock resistance, zeroing provisions, stamped inspection sequence identification, and the Gage R&R acceptance criteria the finished fixture must pass before it is released to production.
They are almost entirely silent about what happens after the indicator moves.
That silence is where most multi-indicator fixtures quietly lose their return on investment. A well-built fixture holds the part in a repeatable datum scheme and reduces the measurement system variation contributed by operator setup. Then an operator reads eight indicators and types eight numbers into a form, and every gain the fixture engineering bought is handed back at the keyboard.
This guide covers the acquisition side of the problem: how to get readings off a multi-indicator fixture, in a controlled order, in the format your SPC software expects, without writing custom software.
The obvious argument for automated gage data collection is transcription error. It is a real argument and it is well covered elsewhere. On a multi-indicator fixture there is a second failure mode that is considerably more dangerous, and it is specific to multi-channel stations.
Consider an eight-indicator fixture checking eight balloon characteristics. The operator presses send on each indicator in turn, and the readings land sequentially in the eight characteristic fields of the SPC record. Reading order is therefore an operator-controlled variable.
Now transpose two of them. Characteristic 4 receives the value from characteristic 6, and characteristic 6 receives the value from characteristic 4.
Nothing flags. No field is blank, no value is out of range, no format error occurs. Both readings are plausible dimensional values in plausible units. If both characteristics happen to be within tolerance, the SPC record shows a conforming part and both control charts remain in control. The nonconformance is not detected because it was never detectable.
This is a channel-level variant of a failure mode we’ve documented in detail elsewhere: transposition error is usually described at the digit level, where an operator reads a value correctly but reverses two digits recording it (0.2538 becomes 0.2358). On a multi-indicator fixture the same mechanism operates one level up. It is not digits swapped within a reading, it is readings swapped between channels. The detection problem is identical in both cases: a plausible, in-range value lands in the wrong place, and no downstream SPC review can tell.
Framed in control plan language, this is a detection ranking problem. Manual sequential send creates a failure mode with a high occurrence probability (any distraction, any interruption, any new operator) and a detection ranking at or near the worst case, because no downstream control in the process can identify a transposed value. Under IATF 16949 the expected response to that combination is not additional inspection. It is error-proofing: designing the failure mode out of the process rather than adding a control that tries to catch it.
Reading order is exactly the kind of variable that should be a fixed attribute of the fixture, not a behavior of the operator.
Before anything else, count the channels the fixture needs today and the channels the fixture will need after the next engineering change.
A multi-channel gage interface, sometimes called a gage multiplexer or a mux box, consolidates several gage inputs into a single connection to the host computer. The GageWay Pro series is available in three densities:
Model | Gage inputs | Typical Fixture Application |
|---|---|---|
GageWay Pro2 | 2 | Two-indicator comparator stations, simple height or thickness checks |
GageWay Pro4 | 4 | Most single-part checking fixtures, mid-density inspection stations |
GageWay Pro8 | 8 | High-density fixtures, multi-feature bracket and housing checks |
Units chain. A primary unit plus additional secondary units supports up to 72 total gage inputs through a single host connection, in any mix of Pro4 and Pro8 hardware. Each secondary unit requires its own power kit (ADT-USB-NA-KIT), since the primary unit alone draws bus power from the host USB connection.
The practical guidance for fixture builders: specify the channel count against the drawing, then round up one tier. Adding a ninth characteristic to an eight-channel station later means either a second interface and a second host connection, or a chained secondary unit and a reconfiguration. Rounding up at the design stage costs less than either.
This is where a fixture station stops being a collection of indicators and becomes a measurement system.
Every front panel channel on the GageWay Pro8 has its own dedicated read switch port. That alone supports the straightforward configurations: one foot switch per indicator, or a single switch wired to trigger all channels simultaneously. Both are useful and both are available on competing hardware.
What is not available elsewhere is programmable sequencing.
A custom read switch sequence lets a single switch press execute a defined series of reads across any combination of channels, in any order, with configurable pauses and delays between steps. The sequence is defined in the free GageWay Pro Setup Program and written to non-volatile memory in the interface, where it persists across power cycles. Up to four sequences can be stored simultaneously, each up to 150 characters in length. For chained systems, a channel group option extends sequence addressing across the full 72-channel range.
Representative sequences:
The first example is the one that matters for check fixtures. Balloon order on a drawing rarely matches the physical layout of indicators on a fixture. The indicator checking characteristic 1 may sit on the far side of the fixture from the indicator checking characteristic 2. A programmed sequence resolves that mismatch in hardware: the physical layout can follow the geometry of the part, while the data output follows the balloon order your SPC software expects.
The operator presses one switch. The readings arrive in the correct field order every time, on every shift, regardless of who is running the station.
The second example handles the fixtures where the operator has to intervene. If characteristics 3 through 8 require the part to be reclamped, indexed, or rotated, the pause-and-wait step builds that intervention into the sequence rather than leaving it to a work instruction that may or may not be followed.
Each read switch port is independently configurable:
Mode | Behavior |
|---|---|
Single reading | One reading on the connected channel |
Continuous read, press and hold | Reads continuously while held, stops on release |
Continuous read, set count | Executes a defined number of readings |
Continuous read, press to start / press to stop | First press begins acquisition, second press ends it |
Single read, all channels | One reading across every channel from one switch press |
Continuous read, all channels | All channels read continuously while the switch is held |
TIR reading | Min, max, range, and count captured over a defined measurement sweep |
All of this executes in the interface. No host computer involvement, no middleware, no custom application.
Fixtures rarely check static dimensions exclusively. Runout, concentricity, flatness sweeps, and squareness checks all require capturing the extremes of a moving indicator rather than an instantaneous value.
TIR read mode captures minimum, maximum, range, and reading count over a defined measurement window, and it is selectable independently per channel. A fixture can therefore run static single-read capture on channels 1 through 5 and TIR capture on channels 6 through 8, in the same sequence, from the same switch press.
The measurement window is bounded by the switch, which matters for repeatability. Where an operator would otherwise decide when a sweep starts and stops, a foot-switch-bounded TIR window makes the acquisition period an explicit, controlled step. Two comparators can run TIR concurrently, but each channel needs its own read switch: there is no single switch or host command that starts and stops TIR on two channels together. A two-point dynamic check is built with two switches, one per channel, physically triggered together by the operator.
For MSA purposes this is worth noting in your Gage R&R planning. Dynamic characteristics captured manually carry appraiser variation from the sweep timing itself, which is a component of measurement system variation that is easy to overlook and difficult to isolate once it is embedded in the study.
A fixture station is only as useful as its connection to the software that consumes the data, and the correct output depends entirely on what that software can accept.
Keyboard wedge output (USB HID). The interface presents itself to the host as a keyboard. Readings arrive as keystrokes in whatever field currently holds the cursor. This is the correct choice for Excel, Google Sheets, browser-based quality portals, cloud SPC platforms, Access forms, and any custom inspection form. No driver installation and no IT ticket, which matters on validated or locked-down shop floor workstations. Default transfer rate is approximately 72 characters per second, reducible to roughly 30 or 8 characters per second for applications that cannot keep pace. Six keyboard layouts are supported, including USA/Canada, UK/Australia, Mexico/Latin America, French, Belgian, and German.
USB serial output (virtual COM port). The interface presents itself as a COM port. This is the correct choice for dedicated SPC packages that monitor a serial stream, including MeasurLink, InfinityQS, DataPage+, GainSeeker, and comparable platforms. Requires a one-time FTDI VCP driver installation, available at no charge. This output also carries the host command set, which is what you use when the fixture is part of an automated cell.
DB9 RS-232 output. A rear panel serial output for legacy cells, PLC serial links, and equipment that predates USB on the host side. Available on the Pro4 and Pro8. If used as the primary computer connection rather than as a chaining link, the unit requires the power kit, since it is no longer drawing bus power from a USB host.
All three outputs are built into the same unit. Moving between them is a matter of moving the cable to the appropriate rear panel port. There is no separate model to buy, no hardware modification, and no additional purchase. That flexibility is worth more than it appears at specification time: fixtures outlive software platforms, and the fixture you build for a keyboard wedge workflow today may need to feed a COM port when the SPC platform changes in three years.
For fixtures integrated into automated cells, the USB serial port exposes complete programmatic control over every read function on every channel:
Command | Function |
|---|---|
<RA | Read Channel 1 (A) |
<RH | Read Channel 8 (H) |
<R* | Read all channels |
<BA | Begin continuous read — Channel 1 |
<CA00025 | Get 25 continuous readings — Channel 1 |
<I1A | Begin TIR read — Channel 1 |
<D1B00150 | Get 150 TIR readings — Channel 2 |
<SA | Stop continuous read — Channel 1 |
Any application that can write to a serial COM port can drive the station: SPC software, LabVIEW, Python, a custom fixture controller, or a PLC serial interface. The command set is unchanged from previous GageWay generations, so an existing integration migrates without rewriting the host application. The commands above are representative; the complete set is documented in the GageWay Pro User Guide.
Not every characteristic on a fixture is dimensional. Stations that also verify press-fit force, seal torque, or component mass need to acquire from RS-232 instruments alongside Digimatic indicators.
Digital gages plug directly into the 10-pin front panel connectors. RS-232 instruments (force gauges, torque tools, scales, height gages) connect to those same front panel ports through the GW-LC Level Converter Cable. AutoBaud detection identifies baud rate and communication parameters automatically on a current-generation LC cable, which removes the most common commissioning delay on mixed stations. A rear panel multifunction serial port accepts one additional RS-232 device directly.
Supported gage families include Mitutoyo, Mahr Federal, Ono Sokki, Fowler, Starrett, Sylvac, CDI, and any instrument with Mitutoyo-compatible Digimatic output, plus RS-232 devices from Ohaus, Mettler Toledo, and others. MicroRidge supplies interface cables for over 3,500 gage models, so the interface and the cabling ship from a single source with a single point of technical support.
This section is aimed at anyone deploying more than one station, and it is the argument that quality managers tend to find more persuasive than any hardware specification.
All GageWay Pro parameters are configured through the free Windows Setup Program: read modes, output format, data parsing, field separators and end-of-packet characters, channel identifiers, RS-232 channel settings, keyboard layout, and trigger behavior. The program detects the connected interface, reads its current configuration, and applies changes in a single operation. There are no DIP switches, no terminal commands, and no cover removal.
Three consequences matter for a quality system:
Configurable output format means no middleware. Field separators, end-of-packet characters, and channel identifiers are set to match what the SPC software expects. The data arrives correctly parsed and correctly attributed to the right characteristic. Interfaces that are not configurable push that work into a parsing script or a software wedge, and every such script becomes an undocumented piece of the measurement system that nobody owns.
Completed setups save to file. A saved setup is a configuration record. It can be attached to the fixture’s gage record, referenced in the work instruction, and restored verbatim when a unit is replaced. Under ISO 9001:2015 Clause 7.1.5, monitoring and measuring resources must be suitable and maintained as such, and a retrievable, versioned configuration file is straightforward objective evidence that a replacement interface was returned to its qualified state rather than reconfigured from memory.
Setups deploy in batch. Twelve identical fixtures across three plants receive one configuration file rather than twelve independent setup sessions. That removes station-to-station configuration variation, which is a legitimate source of measurement system variation and one that is nearly impossible to detect after the fact, because a misconfigured field separator or channel ID produces data that looks correct in isolation.
Firmware is field-upgradeable through the USB serial port at no charge from the firmware updates page.
Note that several competing multiplexers market the absence of setup software as a simplicity feature. For a single-gage bench that is a fair claim. For a fleet of fixtures under a control plan, “requires no configuration” and “cannot be configured” describe the same hardware, and only one of those two phrasings is useful when your SPC software expects a specific data format.
GageWay Pro does not force a trade-off between the two. For a standard Digimatic gage running in single-read mode, default factory settings work immediately: connect the gage, connect the appropriate output port, and readings flow with no Setup Program session required. The configurability described above is available when the application calls for it. Custom read switch sequences, TIR capture, RS-232 channel parameters, and custom field formatting are not a precondition for basic operation, they are an option layered on top of it. A station with straightforward requirements is running the moment it is plugged in. A station with an eight-channel programmed sequence and a specific SPC field format is fully configurable to match it. Competing hardware built around the absence of setup software has no equivalent path to the second case.
Channel count is not the only constraint on a dense fixture. When eight channels are triggered in rapid succession or run in continuous mode, shared processing becomes the bottleneck.
The GageWay Pro8 carries nine processors: one dedicated to each of the eight gage channels, plus a separate communications processor managing the host interface. Sampling rate on any channel is therefore not limited by activity on another.
The measured result, documented in the GageWay Pro User Guide: eight Mitutoyo gages in continuous read mode over 60 seconds produced 5,230 measurements on the Pro8, compared to 984 on the previous-generation Mx8 interface. That is a 5.3x improvement, and the User Guide notes the count was constrained by how fast the gages themselves could send readings rather than by interface capacity.
For most static check fixtures this is headroom rather than a requirement. It becomes a requirement when the station runs TIR sweeps on multiple channels concurrently, when the fixture is inside a cycle-time-constrained cell, or when SPC subgroup collection frequency is itself a process constraint.
A practical specification checklist for a new multi-indicator fixture:
Validate the full chain before committing to a fleet rollout. Run your actual SPC software against a Pro4 or Pro8 with the real gages and the real fixture, and confirm field mapping and read-mode behavior against a known part. Configuration problems are cheap to fix at one station and expensive to fix at twelve.
How many indicators can one check fixture station support?
— A single GageWay Pro8 supports eight gage inputs through one USB connection. Chained Pro4 and Pro8 units support up to 72 total inputs through a single host connection. Each secondary unit in a chain requires its own power kit.
Can readings be sent in a specific order rather than the order the operator presses send?
— Yes. A custom read switch sequence executes a defined series of reads across any combination of channels, in any order, from a single switch press. Up to four sequences are stored in non-volatile memory in the interface. This is the recommended configuration for any fixture where output field order must match drawing balloon order.
Can different channels use different read modes on the same fixture?
— Yes. Read mode is configured independently per channel. A single sequence can execute static single reads on some channels and TIR capture on others.
How do I capture runout or a flatness sweep automatically?
— TIR read mode captures minimum, maximum, range, and count over a switch-bounded measurement window. The window is defined by the read switch rather than by operator judgment, which removes sweep timing as a source of appraiser variation.
Will this work with my SPC software?
— Keyboard wedge output works with any application that accepts keyboard input, including Excel, Google Sheets, and browser-based quality platforms. USB serial output works with any application that monitors a COM port, including MeasurLink, InfinityQS, DataPage+, and GainSeeker. Both outputs are built into every GageWay Pro unit, so the choice is a cable position rather than a purchasing decision.
Can I connect a force gauge or a scale alongside the indicators?
— Yes. RS-232 instruments connect to any front panel port through the GW-LC Level Converter Cable, with AutoBaud detection of communication parameters. The rear panel multifunction serial port accepts one additional RS-232 device directly.
Does the fixture station need a host computer to sequence readings?
— No. Read switch sequences execute entirely within the interface and persist across power cycles. Host commands are available through the USB serial port for automated cells that need programmatic control, but they are not required for switch-driven operation.
How do I replicate a configuration across multiple identical fixtures?
— Save the completed setup to file in the Setup Program and apply it to additional units. This eliminates station-to-station configuration variation and produces a configuration record suitable for the fixture’s gage documentation.
A checking fixture controls part location and reduces setup variation. It does not control what happens to the reading after the indicator moves, and on a multi-indicator station that gap introduces a failure mode that no downstream control can detect: a transposed reading in the wrong characteristic field.
The remedy is to make reading order and read mode attributes of the hardware rather than behaviors of the operator. A multi-channel interface with per-channel read switch ports, programmable cross-channel sequences, independently configurable read modes, and a saved configuration file turns a set of indicators into a documented, repeatable measurement system.
MicroRidge has built measurement data collection hardware in the United States since 1983 and supports interface cables for over 3,500 gage models. If you are specifying a new fixture or replacing an aging multiplexer, our application engineers will confirm gage compatibility and identify the correct cabling before you order.
Request a Demo Kit and evaluate a GageWay Pro4 or Pro8 on your own fixture for 10 days at no cost and no obligation. We cover shipping both directions within the USA and Canada.
Questions on a specific fixture configuration: call +1-541-593-1656 or email sales@microridge.com.
Riley Tronson is President and owner of MicroRidge Systems, a role held since 2023. Riley brings a strong technical foundation to leadership in measurement solutions. An experienced entrepreneur, Riley has founded and grown multiple software companies, including a venture focused on developing iPhone applications, blending engineering expertise with innovative product development.