Neither unit gives you fault numbers you can trust across models. The i40 BS names its belt weighing faults in words; the I400 weigh belt software uses numbers, but the same fault carries different numbers in different tables. Quote the words on your screen and the software version, and check the belt, the junction box and the speed input before the electronics.
This guide covers the messages, what a calibration involves and the setup traps on both. We’re an independent service company, not a Precia Molen dealer or agent. See the other belt weigher brands we service.
What are the i40 BS and the I400?
The i40 BS is Precia Molen’s belt scale indicator, in a standalone sealed housing (SS), a panel mount (PM) or a DIN rail unit (DR). All three share the same fault wording, but not the same wiring and options. Precia Molen writes the names with a space, “i 40 BS” and “I 400”, so a search that finds nothing is often just the spacing.
The I400 is a larger graphic terminal fed by one or more transmitters over a CAN bus. The transmitter sits near the frame, connects the load cells and doubles as their junction box. With the weigh belt software (WBF) loaded, one terminal can run up to five feeders to a flow setpoint. If yours carries a hazardous-area marking, that marking and its paperwork govern any work on it.
We see these less often than the big brands, and much of this guide comes from Precia Molen’s own documentation.
What do the common i40 BS and I400 messages mean?
Write the message down exactly as it appears, and read the alarm list rather than trusting the display to change colour: the fault colour is an option that has to be switched on. One more trap: the column headed “Fault” in the English i40 BS installation manual isn’t a fault list. It’s the factory default for each setting, a translation artefact from the French.
| Message | What we check first | When to call us |
|---|---|---|
| Out of converter range, or converter fault | Water in the junction box, a crushed cable, a loose terminal, or a weigh idler jammed so the frame is hard against a stop. | If it survives a dry junction box, a cable check and a clear frame. See load cell or junction box fault. |
| Zero impossible | The reading is outside the zero correction band, so the unit declined. Build-up, carryback, or a frame that has moved. | If it’s still refused after a proper clean and inspection. |
| Measurement error when a zero or calibration won’t start | The belt must be running above the configured minimum speed. | If the belt is up to speed and the speed input is being read. |
| Zero fault, segmented tare fault, belt position fault | The segmented zero option can’t find the belt index. Usually the index detector or its target. | If the detector and target check out. |
| Sliding fault (belt slip) | A second detector on the driven drum disagrees with the speed pickup. Belt tension, drive lagging, both detectors. | Straight away: every tonne is wrong in the same direction while the belt slips. |
| Speed fault, or the scale thinks the belt has stopped | Below the minimum speed (normally around half running speed), flow reads zero and totalising stops. Where speed is simulated, check the wired “belt running” input. | If the belt is at normal speed and still reads as stopped, or it totalises with the belt stopped. See no speed signal. |
| Flow outside its limits | Minimum flow is a fifth of maximum, so a scale set up for a design tonnage the plant never runs trips all day. | If the plant is in its normal range. See wrong at low flow. |
| Minimum or maximum load per metre (I400 feeder) | Low: a bridged bin or blocked chute. High: a surge, a plugged discharge or a frame being held. Either can be set to stop the belt. | If the feed looks normal and it still trips. |
| Transmitter fault (I400) | CAN bus wiring, terminations and the transmitter’s supply. | If the bus and supply check out. |
| Parameter fault | Inconsistent configuration, usually after an edit or a restore. | If you can’t trace it to a recent change. |
On the I400, belt centring, belt position and regulator fault alarms can come from field devices such as a tracking switch or a drive fault contact. When one won’t clear, check the switch on the conveyor first.
What does a calibration on an i40 BS or I400 involve?
Work on or near a conveyor, or inside an electrical enclosure, needs isolation under your site’s procedures and trained, authorised people. If that’s not you, stop and call us on 1300 101 666.
The standalone indicator’s housing carries mains voltage, so it’s off before the housing is opened or a memory card goes in or out. On a feeder, isolate the drive too. Production totals stop from the start of a dynamic calibration until the reference is removed and acknowledged, so warn the control room.
- Speed and belt geometry: drum circumference, pulses per revolution of the sensor actually fitted, minimum speed, weighing length, and a control length of whole belt revolutions. More than about 2% off a measured speed needs investigating. After a new belt or splice, re-measure speed and length and re-enter them.
- Static zero, then dynamic zero. The static zero is coarse, for commissioning or a big change. Follow it with a dynamic zero over the control length on a clean, empty belt. On a dirty belt it keeps re-running and never settles.
- Dynamic span with a reference weight on the frame, over the control length. Precia Molen say static calibration is for factory setup only. Test weights or a chain put real force through the frame.
- Material check. A separate material coefficient reconciles the scale to an independently reweighed quantity. Keep it as its own adjustment so the span underneath stays visible.
A verification mode runs the same procedure but only shows the difference: the right tool for an as-found figure. Ours is maintenance calibration for production; trade verification is a separate regulated activity.
The numbers we work to: repeat span runs within about 0.1%, and a routine span that has moved more than about 0.25% needs attention.
Who adjusts what. On our service visits we adjust the zero and span when the checks show it’s needed. Between visits, site should run a zero about every two weeks and after a big change in the weather, and check the span but record it rather than accepting it. We recommend a service calibration every quarter so the scale keeps up with the seasons. See belt weigher calibration methods.
Why does the zero or span move on one of these?
Something under the belt changed: build-up and carryback, a binding tie rod or pivot, a seized idler, belt tracking, water in a junction box. After a proper clean, a one-off zero change of about 1% is normal. A zero that keeps walking needs investigating, not re-zeroing. Span moves when a cell is replaced, the frame is knocked, or the belt or its tension changes. A new belt beds in over a week or two. See why a belt weigher zero drifts and span drift after belt work.
Two settings look like drift and aren’t. Below a quarter of the zero threshold the unit stops totalising, so a light trickle is thrown away. Heavy filtering reads on a trend as a scale gone slow. See erratic totals.
What speed sensor and load cell points matter?
Speed. The scale works from pulses per revolution and drum circumference, so change a sensor or target and you revisit both. A scale set up for Precia Molen’s own speed roller and fitted with something else reads wrong without complaining. Where a sensor is worn out, our USR speed sensor is an option. It mounts on the tail drum or a trailing arm, and its multiple outputs mean one sensor can feed two belt weighers, or a belt weigher plus the conveyor underspeed. We’ll confirm it suits the input first.
Load cells. The i40 BS takes the cells at its own terminals. The I400 transmitter has four cell connectors and switches for four-wire or six-wire operation. Check that switch when a scale reads right in the cool of the morning and drifts through the day: with the sense pair not in use on a long cable, voltage lost down the cable reads as a calibration error. See the load cells guide.
The sealed housing. Refit the seal and the earth straps, and tighten evenly in a star pattern. A housing closed carelessly after a fault-find is the water ingress call-out two wet seasons later. See protecting belt weigher electronics.
What’s different about an I400 running the weigh belt software?
It closes the loop, holding measured flow to a setpoint. The documentation calls this “regulation”. Three things to know:
- Each alarm is configured. The site sets whether each condition is watched and whether it stops the belt, so one feeder trips on a condition its neighbour only displays.
- The mode changes what alarms do. Local mode, meant for emergencies and maintenance, raises no alarms at all, so a feeder left there runs blind. In emergency mode the terminal isn’t controlling and only the flow reading is live.
- It can drop into open loop without stopping. Below minimum flow, or with belt speed outside its band, the feeder runs at a fixed speed calculated from the setpoint. Density changes go straight into the tonnes, and it only alarms if that alarm was configured.
The compensation distance, for material dropped on upstream of the weighing section, is a real measurement on the structure. Get it wrong and the loop hunts however it’s tuned.
Need a manual for your equipment?
Three documents get asked for under this heading: the i40 BS installation manual, the I400 terminal manual and the weigh belt software manual. Tell us the housing letters on an i40 BS (SS, PM or DR), or the terminal and transmitter details on an I400 and whether the weigh belt software is loaded, plus the software version the screen reports.
Talk to us about manuals for your equipment. Send the make, model, serial number and software version (a photo of the label is fine) and we’ll help you find the right document.
When should you call us rather than keep resetting it?
Call when the same message returns after the obvious cause has been dealt with: a converter fault that survives a dry junction box, a zero refused after a proper clean, a slip or speed fault that outlives a look at the sensors, totals that no longer agree with the weighbridge, or a unit that has lost its configuration. Call sooner on a feeder: a wrong number there puts the wrong amount of material into the process while every screen looks healthy.
Both platforms can back up their own settings (the indicator to a memory card, the terminal to a USB stick), so ask us to take a copy while we’re on site. We supply parts for Precia Molen and the other major belt weigher brands: a genuine part where it’s available, or a suitable alternative, with compatibility confirmed and the part identified on the quote. Call 1300 101 666 or see booking a belt weigher service.
Frequently asked questions
What do the Precia Molen i40 BS fault code numbers mean?
There are none for belt weighing: the i40 BS names its faults in words, and sends them to the PLC as individual flags. The I400 feeder software gives one condition different numbers in the alarm file, the PLC status word and the output table, so quote the wording instead.
Why has my belt scale stopped totalising while the belt is still running?
Usually one of three: the measured speed has dropped under the minimum that counts as running, the load is under the low cut-off so a light trickle is discarded, or a dynamic calibration or zero is under way and blocking the totals.
Do you need to stop the conveyor to calibrate one of these?
The belt has to be handed over. The zero needs it running empty at normal speed, the span needs a reference on the frame, and production totals are blocked meanwhile. We plan around a shutdown or a changeover where we can.