A Tecweigh WP50 reports in plain English messages, not numbered codes, so the exact words on the screen are what you look up. Most of what it shows is status, not failure. The messages that mean the scale has stopped weighing are bad scale card comms, low scale power, load out of range, zero belt speed and interlock open, and those are the ones worth a call.
This guide sorts the WP50’s messages into status, faults, calibration results and alarms. We’re an independent service company, not a Tecweigh dealer or agent. For bookings and parts, see Tecweigh belt weigher and WP-series servicing. For the older processors, see Tecweigh WP20 and WP25 fault codes and calibration.
Why is there no fault code list for the WP50?
Tecweigh processors don’t number their faults, so write down the exact wording. It also dates the unit: bad scale card comms is WP50 wording for what the WP20 and WP25 call a scale data error.
If more than one alert is active, arrows appear and the arrow keys step through the queue. An alert clears once viewed if the cause has gone, and stays if it hasn’t. Many alerts only exist when the matching feature is set up, so two WP50s on one site can show different messages.
Which WP50 messages are just status?
- Self test. Normal at power up. It also shows after any reboot, so a self test mid shift with nobody at the panel means the unit restarted itself. Chase that: supply, a loose terminal or surge.
- Rate in deadband. The rate is inside a window either side of zero, so nothing totalises. Right on an empty belt; wrong if the window is wider than your lowest running rate, because real material then goes uncounted. See why a Tecweigh under-reads at low rate and why a belt weigher is only wrong when the belt runs light.
- Auto zero tracking. The processor is about to zero itself. The manual doesn’t recommend tracking where material can start flowing during an automatic zero. See why a belt weigher’s zero drifts.
- Calibration prompts. The wait and countdown during a zero, the lower and raise weight prompts, and the calculating message during an electronic span.
- Batch complete. A success message, but it’s also a flag in the comms card’s error value, so a PLC that alarms on any flag will alarm on a good batch.
- Firmware updated (main board or display board). Confirmations only.
- Dashes across a value. The number is too big for the digits, or a total has gone negative. Change the decimal point setting or reset the total.
Which WP50 messages mean the scale has stopped weighing?
Load, belt speed and scale status all come back from one scale card at the weigh frame over one digital link. That’s why a comms fault takes out everything at once. While any of these is showing, treat the rate and total as unmeasured.
| Message | What we check first | When to call us |
|---|---|---|
| Bad scale card comms | Indicators at both ends, then the cable, glands and terminals. See bad scale comms or scale data error. | If the cable looks sound and it’s still down, or it comes and goes. |
| Low scale power | The voltage at the scale card is below the threshold for that card type. Measure at the frame, and ask what’s been added to the supply. | If the supply at the frame checks out. |
| LOW POWER | The older style supply message: incoming supply, an over-length run, other devices on the supply, or a break or short in the cable. | If the supply, cable and added loads check out. |
| Load out of range | Does the raw load count rise when the calibration weight goes down? See load error or load out of range. | If the count doesn’t respond, or it comes and goes. |
| Zero belt speed | Is the belt moving? Is the speed indicator on the scale card blinking? A fast blink looks solid. See zero belt speed on a running belt. | If the wheel is turning and there’s still no speed. |
| Interlock open | Totalising pauses. Find the plant signal the interlock input is waiting for. | If the signal is there and it won’t clear. Never bypass the interlock. |
| Bad display comms | The main board keeps weighing. Cycle the power, then check the connections between the boards. | If it’s still dead. The display board is next. |
Scale comms and load are the two we’re called out for most on Tecweigh sites, usually from long buried cable runs, water at glands, vibration or storms. We don’t quote a supply voltage, because three generations of scale card are in service with different thresholds. Don’t calibrate while any of these is showing: a reference taken over a bad signal puts every tonne out from then on.
What do the WP50 calibration messages mean?
These three are almost always about the belt, the weights or the order of the steps, not the processor.
| Message | What we check first | When to call us |
|---|---|---|
| Zero counts low | Shipping stops still fitted, material jammed under the weigh idler, or the weight in the wrong position. | If the frame is free and the weight is right. |
| Span counts low | Was the weight lowered? Is skirting or material touching the weigh idler? | If the count doesn’t rise when the weight goes down. |
| Span below zero | The weight the wrong way round for one of the steps, or material still running. | If the weight sequence was right. |
Always zero before you span, and check the raw load count goes up when the weight is lowered. If the belt stops mid cycle, the cycle waits indefinitely, so cancel it and start again. See why a Tecweigh won’t finish its zero or span.
A zero or span started from a digital input, the serial port or a comms card is refused if it would move the reference by more than about 5%, and the display shows out of range. At the keypad the same change raises an error you can accept. After a proper clean, a one-off zero change of about 1% is normal; a zero that keeps walking needs investigating, not re-zeroing.
When a cycle finishes, the WP50 shows the percentage change and asks you to accept or reject it. Read the number. A routine span that has moved more than about 0.25% needs attention, and if site staff check the span between our visits, record the result rather than accepting it.
Do the rate, speed and total alarms mean something’s wrong?
Usually not. High and low material rate, high and low belt speed, and high total 1 and 2 only exist where a relay is set to that function, often with limits typed in at commissioning and never revisited. Setting one speed limit to zero turns off that half. If an alarm chatters, look at the relay delay before the limits. Fix nuisance alarms: a list operators ignore is where a real message hides.
Feed control rate high and low, batch cycle out of range, batch timed out and batch prestop low belong to the WP50’s feed and batch modes, and don’t appear on a plain belt weigher.
Does locking the zero, span or total reset actually lock it?
It locks the keypad, not the calibration. Auto zero lock, auto span lock, reset total 1 lock and reset total 2 lock show when someone tries a locked function at the panel. The manual says each lock only covers the keypad, so the same functions still work from a digital input, the serial port or a comms card. See locked out of your integrator.
The same security menu holds a dated parameter save, a restore and a factory reset. Check a current save exists before anyone changes settings. See Tecweigh back on default settings.
Can your control system see which message is active?
Over the plain serial port, status is one character: it flags an alarm or a load error but can’t name the alarm. With a comms card fitted, every alert is its own flag. With neither, a relay set to the error function covers a scale data error, a load error or low power, the three faults that stop the scale weighing. See getting Tecweigh WP50 faults into the PLC.
Bad auxiliary comms means corrupt or missing data on the auxiliary serial port, which is a plant link problem, not a weighing one.
What can your site check, and in what order?
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.
- Write down the exact wording and step through the queue. Note which messages clear once viewed.
- Ask who’s worked on the scale, conveyor or switchroom lately.
- Check it isn’t in simulation or on manual speed. Both are legitimate for testing or while a speed sensor is on order, both are invisible from the control room, and a unit left in either sends made up numbers to every output.
- Run the keypad test before blaming the display board. More than one indicator means keys are shorted together.
- Read the scale comm errors count in the maintenance menu. A healthy hard wired link sits at zero; a count that’s climbing visit on visit is a cable starting to fail. We keep these figures against the asset in AIMM, our asset management system.
If the rate is steady but wrong, check the weigh span and belt length settings: either left at zero gives a wrong calibration with no message. For noise, surge and welding damage, see protecting belt weigher electronics.
No message tells you whether it’s the cable or a board: that takes readings at both ends. We keep the settings of the scales we look after, and the WP50’s protected edit mode lets the stored zero count, span count and odometer go into a replacement board, so a board swap is a reload, not a recommission. For faults common to every brand, see common belt weigher faults.
We supply parts for Tecweigh 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.
Need a manual for your equipment?
More than one WP50 manual revision is in circulation, and a comms card has its own supplement, so note the software version of both boards and whether a card is fitted. The manuals give imperial figures first, so convert any figure before you use it.
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 a message that stops the weighing won’t clear, keeps coming back or comes and goes, when the unit restarts itself more than once, or when nobody has a record of its settings. Call before anyone calibrates over a fault, and note when the message first appeared: that’s the window of tonnes you’ll need to account for. If a board has failed, we’ll tell you straight whether to repair it or replace it. Call 1300 101 666 or email admin@accurateindustries.com.au with a photo of the screen. See booking a belt weigher service.
Frequently asked questions
Where’s the fault code list for a Tecweigh WP50?
There isn’t one. Every WP50 message is plain English, so write down the exact words. They also tell us whether you have a WP50 or an older WP20 or WP25.
My WP50 says bad scale card comms. Are today’s tonnes any good?
No. Load, speed and scale status all come over that one link, so there’s nothing behind the rate or total. Treat the period as unmeasured, not low.
Why was our remote zero refused?
A zero or span started remotely is refused if it would move the reference by more than about 5%. Do it at the keypad, and find out why the zero moved that far before you accept it.
Our WP50 restarted by itself and showed self test. Does that matter?
It can. One unexplained restart is worth noting; a pattern of them is worth a visit to look at the supply, terminals and surge protection.