LT DIN Rail Digital Transmitter for Batch Controller Pulse Input Applications

Batch Controller Pulse Input Transmitter Frequently Asked Questions

Why does the same pulse signal need to go to two separate input channels?

Channel A and Channel B are configured to process the identical signal differently — one for totalizing, one for rate — since the transmitter's internal counting and inverse-period timing logic for these two functions are handled independently; feeding both channels the same signal in parallel lets both calculations run simultaneously from a single flow meter.

What's the difference between counting up to a preset and counting down from a preset?

Counting up from zero displays the accumulating batch progress toward a target, while counting down from a preset to zero shows the remaining amount needed to complete the batch; the choice is a display preference, since both track the same underlying quantity and can trigger the fill-complete relay action at the same point.

Can the second tracked item be grand total in one batch run and batch count in another?

Yes — the second item is independently assignable to either grand total (a cumulative sum across all batches) or number of batches completed, so the same hardware can be configured for whichever of those two summary values matters more for a given application.

How is the delay between batches actually used in a real fill sequence?

The delay (10 ms to 199.99 s) provides a pause after one batch completes before the next one starts, useful for allowing a valve to fully close, a container to be swapped, or a brief settling period, rather than starting the next fill cycle immediately upon completion of the previous one.

Why would I choose solid state relays over magnetic relays for batch control?

Solid state relays are rated for lower current (120 mA) but switch faster and have no moving parts to wear out over repeated cycles, which matters in high-cycle-count batch applications; magnetic relays handle higher current (8A) directly but are better suited to lower-cycle-count applications given their mechanical wear characteristics.

What does QA passband hysteresis mode do in a batch control context?

It defines an acceptable band around a target value where the relay behaves differently inside versus outside that band, which can be used to distinguish a batch that completed within tolerance from one that over- or under-filled, rather than only detecting a single pass/fail threshold.

Does using an external control input to trigger the next batch require the programmable delay to be disabled?

No — the two triggering methods (programmable delay or external control input) serve different scenarios, and the transmitter's configuration determines which one governs when the next batch begins; an external trigger is typically used when the next batch depends on an outside condition rather than simply elapsed time.

Can custom curve linearization be applied to the rate channel, the total channel, or both?

Custom curve linearization corrects for a transducer's own nonlinearity at the point where the signal is processed, so it applies to whichever channel (rate or total) is derived from that nonlinear signal — in practice, since both channels read the same flow meter signal, linearization benefits both the rate and total readings together.

What frequency range does the turbine flow meter input support?

Each channel independently accepts pulse rates up to 250 kHz on Channel B (used for rate) and up to 1 MHz on Channel A (used for totalizing), which comfortably exceeds the working frequency range of typical turbine flow meters.

Can multiple batch controllers be networked together?

Yes — up to 30 LT Transmitters and/or Digital Panel Meters can be daisy-chained on RS485 for LAN integration, or a high-speed Ethernet or WiFi communication board can be used instead for network connectivity.

Batch Controller Pulse Input Transmitter Questions From the Field

My batches consistently finish slightly over or under the target total — what should I check first?

A consistent, repeatable overshoot or undershoot usually points to valve or fill mechanism lag rather than a measurement error — the flow meter registers the actual delivered volume, but the physical shutoff isn't instantaneous; adjusting the preset target to account for known dispense lag, or introducing a setpoint offset if supported, is the standard fix.

My rate reading and total reading seem inconsistent with each other even though they're from the same signal — why?

Since rate and total are calculated independently from the same underlying pulse signal but with different scaling factors configured on each channel, an apparent inconsistency usually traces to a scaling mismatch between the two channels rather than a genuine conflict in the measured signal; verifying both channels are scaled consistently for the same physical flow meter is the standard check.

My batch controller doesn't automatically start the next cycle — what should I check?

Confirming whether the unit is configured for a programmable delay or an external control input to trigger the next batch, and verifying that trigger condition is actually being met, is the first step — a unit configured for external triggering won't automatically cycle on a timer, and vice versa.

My relay doesn't shut off the fill valve exactly at the target — what's the likely cause?

This is commonly the same physical dispense lag issue seen in overshoot/undershoot troubleshooting — the relay itself typically responds quickly, but the valve and any material already in transit downstream of the sensor take a moment to fully stop; verifying relay response against the raw pulse count timing (rather than assuming the valve itself is slow) helps isolate whether the lag is electronic or mechanical.

My grand total doesn't match the sum of individual batch totals I've recorded manually — why?

Confirming whether the second tracked item is actually configured for grand total (rather than batch count) is the first step, since a unit configured to display batch count instead of grand total won't accumulate volume at all, which would explain a mismatch against manually summed batch volumes.

Can noise on the pulse input cause a batch to complete early or late?

Yes — electrical noise misread as legitimate pulses can add false counts to either channel, causing a batch to appear to complete earlier than the true delivered volume; checking cable shielding, grounding, and the selected noise filter setting is the standard remedy for unexplained early batch completion.

My batch delay timer seems to run longer than the configured value — what should I check?

Confirming the configured delay units and value in setup software match what's actually intended (since the range spans milliseconds to just under 200 seconds) is the first step, as a delay value entered in the wrong units or magnitude would produce a timing discrepancy that looks like a fault but is actually a configuration mismatch.