LTE DIN Rail Digital Transmitter with Ethernet Communication and Analog Outputs for Pulse to 4-20 mA Converter for Frequency, Rate, or Period Applications

LTE Frequency, Rate, and Period Transmitter Frequently Asked Questions

Why does Channel A support a higher maximum frequency (1 MHz) than Channel B (250 kHz)?

The two channels are designed with different circuit paths, with Channel A optimized for high-frequency signals up to 1 MHz — suited to fast pulse trains from sensors like encoders — while Channel B is tuned for the somewhat lower frequencies typical of flow meters and rate sensors used in dual-channel arithmetic applications.

What's the practical difference between frequency, rate, and period output modes?

Frequency mode reports pulses per second directly. Rate mode scales that pulse rate into application units, like gallons per minute. Period mode reports the inverse of frequency — the time between pulses — which is useful for slow-speed applications where frequency alone would report an inconveniently small number.

Does the Ethernet interface affect measurement accuracy or update rate?

No — accuracy and update rate come from the same quartz-referenced signal conditioning used across the frequency/rate product line; Ethernet only changes how the reading is transmitted digitally rather than over serial data.

When is custom curve linearization needed for a turbine flow meter?

Turbine flow meters often produce a pulse frequency that isn't perfectly proportional to flow rate at the low end of their range. Custom curve linearization, using up to 180 data points and a spline-fit approach, corrects for that nonlinearity and extends the usable accurate range of the meter rather than relying on a single linear scale factor.

What's the difference between the A-B and A/B arithmetic functions?

A-B computes the numeric difference between the two channels, useful for net flow (inflow minus outflow). A/B computes a ratio between the two channels instead, useful for applications like ingredient mixing where the proportion between two flows matters more than their absolute difference.

Can this transmitter power the sensor connected to it?

Yes — the isolated 5V, 10V, 12V, or 24V DC transducer excitation output can power magnetic pickups or two-wire proximity switches directly, so an external power supply for the sensor isn't necessarily required.

Does contact debounce affect measurement accuracy on a clean electronic signal?

Contact debounce settings (0, 3, or 50 ms) are meant to filter out the mechanical bounce of physical switches and relays; a clean electronic signal like a proximity switch or magnetic pickup typically doesn't need debounce filtering and can use the 0 ms setting without affecting accuracy.

Can this transmitter measure AC line frequency directly from mains voltage?

Yes — it accepts AC voltage inputs up to 250 Vac directly and can output line frequency to 6-digit accuracy (50.0000 or 60.0000 Hz) within a few line cycles, without needing a separate step-down or isolation transformer ahead of the input.

Do I need a gateway device to connect this transmitter to my network?

No — the transmitter connects directly to a LAN via its own RJ45 jack over Modbus TCP, without requiring a separate RS485-to-Ethernet gateway.

Can multiple frequency/rate transmitters be networked together?

Yes — the transmitter supports up to 247 digital addresses via Modbus TCP, allowing many individually addressable transmitters to coexist on the same Ethernet network.

LTE Frequency, Rate, and Period Transmitter Questions From the Field

My flow rate reading is accurate at high flow but reads inconsistently at low flow — what's the likely cause?

Inconsistent low-flow readings from a turbine flow meter often point to the meter's inherent low-end nonlinearity rather than a transmitter fault; setting up custom curve linearization with data points specifically covering the low-flow region typically resolves this.

My RPM reading is intermittent or drops out occasionally — what should I check first?

Intermittent dropouts from a magnetic pickup are commonly caused by the sensor gap being too large or misaligned relative to the target, producing a signal that falls below the minimum detectable level intermittently; verifying sensor gap and alignment is the standard first troubleshooting step.

My combined A+B total doesn't match the sum of the two individual channel readings — why?

This usually points to a scaling mismatch between the two channels rather than an arithmetic fault, since A+B sums the two channels' scaled engineering-unit values; if each channel isn't scaled to consistent units before the arithmetic function is applied, the combined result won't match a manual sum of the raw displayed values.

My transmitter isn't showing up on the network — what should I check first?

Confirming the transmitter's IP configuration matches what the network expects, and that the physical Ethernet cable and switch port are functioning, are the standard first checks before suspecting a transmitter fault.

My pulse input from a mechanical switch produces multiple counts per actual switch closure — what's the fix?

This is a classic symptom of mechanical contact bounce; increasing the contact debounce setting (from 0 ms to 3 ms or 50 ms as needed) filters out the rapid multiple transitions a mechanical switch produces during a single physical closure.

Can electrical noise from nearby VFDs affect a high-frequency pulse input?

Yes — high-frequency pulse inputs are susceptible to noise coupling from variable-frequency drives and similar switching equipment; checking cable shielding, grounding, and physical separation from the noise source, along with using an appropriate noise filter setting, are the standard remedies.

My Modbus TCP polling occasionally times out even though the transmitter appears connected — what's the likely cause?

Network congestion or too many devices polling the same transmitter simultaneously can cause intermittent timeouts; checking polling frequency from all connected clients and network traffic load is a common troubleshooting step.

My totalizer resets unexpectedly — what could cause that?

An unexpected reset is often traced to the external reset input being triggered inadvertently, whether by wiring, a control signal, or a configuration setting; checking the reset input wiring and the conditions configured to trigger it is the standard first diagnostic step.