LTE Series DIN Rail Digital Transmitters with Ethernet Communication for Time of Single or Accumulated Event Applications

LTE Time of Single/Accumulated Event Transmitter Frequently Asked Questions

Why does tying Channel A and Channel B together specifically allow measuring the duration of a single wave shape?

Documented description specifically explains this configuration starts the stopwatch with one signal polarity and stops it with the other polarity — since a single pulse or wave shape inherently transitions from one polarity state to the other and back, tying A and B together lets the transmitter treat the rising and falling edges of that same single waveform as the start and stop triggers, directly measuring that waveform's own duration.

Why does the documented long-term drift figure (±5 ppm/year) matter separately from the ±2 ppm time base accuracy figure?

These are documented as addressing different timescales of the same underlying quartz crystal reference — the ±2 ppm figure describes the crystal's accuracy at calibration, while the separately documented ±5 ppm/year long-term drift describes how much that accuracy is expected to shift over the course of a year; both figures are relevant together for understanding total expected timing error at some point after the original factory calibration.

Does this LTE Stopwatch transmitter's documented Modbus TCP-only protocol limit compatibility compared to the RS232/RS485 LT Series stopwatch variant?

Yes — this page documents Modbus TCP specifically as the supported Ethernet Data I/O protocol at digital address 247, while the LT Series serial variant is documented elsewhere as separately supporting Modbus RTU/ASCII and Laurel Custom ASCII; a control system needing a protocol other than Modbus TCP would need to reference the LT Series serial variant rather than this LTE Ethernet variant.

Can decimal time format and HH.MM.SS clock format both be viewed simultaneously, or is one selected exclusively?

Documented specification lists these as "Selectable Decimal Time" and "Selectable Clock Time" as two distinct format options — the documented phrasing "selectable" for each is consistent with the display format being a configuration choice between the two, rather than both formats being simultaneously available on the display at once.

Does using relay-generated start/stop pulses (as in the documented "Timing Process Dynamics" application) introduce any additional timing delay beyond the transmitter's own resolution?

The page documents this application without detailing the relay's own switching time as a separate error contributor — since the transmitter's own resolution is documented down to 0.2 µs, while relay switching times are documented elsewhere in the LTE Series specifications as being on a millisecond timescale, any relay-introduced delay would be expected to be far larger than the transmitter's own timing resolution for applications with millisecond-or-longer event durations.

Does measuring pulse width (as mentioned in the documented laser system application) use A-A mode, A-B mode, or the tied-together A/B configuration?

The page documents pulse width as one of several measurable parameters in the laser system application without specifying which exact stopwatch mode configuration is used for that particular measurement — based on the documented general description elsewhere on the page (that duration of a single wave shape is measured by tying A and B together), the tied-together configuration is the one specifically documented as suited to measuring a single pulse's own width.

Can the four documented A-B edge combinations (+/+, +/-, -/+, -/-) all be used interchangeably for the same physical measurement, or does the choice matter?

The choice matters and depends on the actual signal characteristics of the specific start and stop sources being used — since Channel A and Channel B can originate from genuinely different sensor types with different documented polarity conventions, selecting the edge combination that matches the actual rising or falling transition each specific sensor produces for the "start" and "stop" events is necessary for the transmitter to trigger at the intended physical moment, rather than the four combinations being freely interchangeable for a given real-world setup.

Does the documented 25/sec maximum stopwatch output update rate limit how short an event this transmitter can actually time?

No — the 25/sec figure describes how often the display and output are documented as refreshing during an ongoing timing measurement, distinct from the separately documented minimum timing interval of 1 µs and resolution down to 0.2 µs, which describe the transmitter's ability to measure a single short event's duration; a very short single event is still captured and reported at its own precise duration, even though continuous updates during a longer event are documented as limited to 25 times per second.

Does power consumption increase specifically when using the maximum transducer excitation output, and by how much per the documented specification?

Yes — documented specification lists power consumption as "2.5W typical at 24V, 4.0W with max excitation output," directly quantifying the additional power draw when the transducer excitation output is set to its maximum documented level; this represents a genuine, specified increase in overall power consumption tied directly to how much excitation current is being supplied to an external transducer.

Can the same physical transmitter be reconfigured between A-A stopwatch mode and A-B stopwatch mode, or does each require separate hardware?

Documented description presents A-A mode, A-B mode, and the tied-together configuration as different wiring and setup configurations of the same underlying FR dual-channel pulse input signal conditioner, rather than as separate hardware options; this is consistent with mode selection being a configuration choice on shared hardware, not a distinction requiring different transmitter models.

Quartz Crystal Oscillator Aging & Drift Questions From the Field

What specifically causes a quartz crystal's frequency to drift over time (aging), separate from temperature-driven changes?

Documented technical analysis specifically identifies mass loading and mechanical stress changes as the two most significant causes of crystal aging — mass loading refers to subtle changes in the quartz resonator's own mass from absorption or desorption of trace contaminants (commonly water vapor) inside its sealed package, which is documented as a genuinely different mechanism from the reversible, temperature-driven frequency shifts that occur even when a crystal isn't aging at all.

Is there a documented typical range of first-year aging rates across different grades of crystal oscillator?

Yes — documented industry figures specifically cite aging rates ranging from about ±1 to ±5 ppm in the first year for standard crystal oscillator circuitry, dropping to a documented ±0.2 to ±1 ppm first-year rate for temperature-compensated (TCXO) and oven-controlled (OCXO) crystal designs; these documented figures illustrate a meaningful difference in aging performance across oscillator grades.

Does crystal aging follow a straight linear rate over many years, or does documented behavior show a different pattern?

Documented analysis specifically describes aging as following an approximately logarithmic pattern, with the largest frequency changes occurring early in a crystal's life and the rate of change significantly slowing in subsequent years; documented guidance specifically cautions that a crystal rated at ±5 ppm/year aging does not necessarily drift by ±25 ppm after five years, precisely because of this documented logarithmic (front-loaded) aging behavior.

Is aging drift documented as a one-way, permanent process, or can it reverse if environmental conditions return to normal?

Documented analysis specifically distinguishes aging from temperature-driven frequency stability changes on exactly this point — temperature stability is described as a reversible change that returns to baseline once environmental conditions return to normal, while aging is documented specifically as a one-way drift that continues to accumulate over time even under otherwise constant environmental conditions.

Is there a documented practical method for reducing a crystal's early-life aging drift before it's put into critical service?

Yes — documented manufacturer guidance specifically recommends specifying pre-aging or burn-in for crystals intended for demanding timing applications, since aging is documented as most pronounced in the earliest period of operation; running a crystal through this burn-in period before deployment is documented as a way to reduce the amount of early-life drift the end application will actually experience.

Does keeping a crystal oscillator continuously powered under stable conditions genuinely affect its long-term aging performance compared to frequent power cycling?

Yes — documented guidance specifically states that keeping an oscillator powered under steady operating conditions typically yields the best long-term frequency stability, implying that frequent power cycling and associated thermal or mechanical stress transitions are documented as working against optimal long-term aging performance compared to continuous, stable operation.

Is there a documented difference between how an oscillator's "aging" specification and its real-world "drift" behavior are defined?

Yes — documented technical description specifically distinguishes aging (a roughly predictable frequency change measured under controlled evaluation conditions and specified in a datasheet) from drift (what's actually observed in a real deployed application, which documented analysis notes includes aging plus additional changes from the surrounding environment and other external factors); this means real-world drift can exceed the datasheet aging specification alone once environmental factors are included.

Is crystal aging rate documented as a fixed, identical value for every unit of the same crystal model, or does it vary unit to unit?

Documented technical guidance specifically describes aging as following a statistical distribution rather than a single fixed value, meaning per-unit drift genuinely varies even among crystals of the identical model and specification; documented manufacturing practice specifically notes that production screening and burn-in are used to narrow this unit-to-unit spread, rather than aging being treated as a single deterministic number applicable identically to every individual crystal.