The Micro-Tech 9101 is one of the most common belt weigher integrators on Australian mine and quarry sites, and the 9201 is its sibling on a premium A/D board, held to a tighter span limit. This page covers what the alarms mean, what a calibration involves, and what we find behind them. For weigh frames and scale codes, see servicing Thermo Ramsey belt scales and Micro-Tech integrators.
What are the Micro-Tech 9101 and 9201, and where do we still see them?
They are belt weigher integrators: the box that takes a load signal from the weigh frame load cells and a pulse train from the speed sensor, multiplies the two, and reports a rate in t/h plus a running total in tonnes. Every alarm, output and calibration routine hangs off that one calculation.
The 9101 has two load cell inputs; the 9201 has one, on a premium A/D board. Either runs up to six load cells in parallel, and plenty are decades old and still weighing well. Thermo discontinued both in September 2022, with service continuing subject to parts availability. We keep them running, and when one is past saving, talk to us about replacement options. We’re an independent belt weigher service company, not Thermo Fisher and not a Thermo Fisher agent, and we service these alongside every other brand on the same visit.
What do the common Micro-Tech error messages mean?
An alarm names a category, not a cause. It says which part of the system stopped making sense, and the answer is usually on the belt, in a junction box or in the setup data.
Load Cell Fail. The unit no longer trusts the load signal on a weigh channel. Check the junction box, the cabling and the sense jumpers before suspecting the cell. It becomes a call-out when the millivolt reading is still wrong with the field wiring disconnected.
Clock Fail, RAM Fail and ROM Fail. Faults in the integrator’s own electronics, not the scale. Note exactly what the display shows, don’t keep power-cycling it, and call us.
Auto zero tracking alarm. The automatic zero trim has moved further than the limit set for it, so the unit alarms rather than keep chasing the zero. Check the frame for build-up, carryback, a binding idler or a stiff tie rod, then re-zero after a proper clean. Call if it comes straight back, and see why a belt weigher zero drifts.
High and low rate, load and speed, and belt slip. Process alarms the site configures itself, against percentages of capacity, belt loading and belt speed. Check whether the plant condition is real before touching the scale. A low speed alarm on a visibly running belt is a speed sensor fault and needs a visit.
A word on cold starts. A cold start wipes the setup and returns the unit to its start-up state, so everything that defined the scale has to go back in. Keep a USB backup of the settings: the unit can save and restore them.
What does a Micro-Tech 9101 calibration involve?
Three things in order: a zero on an empty belt, a span against a known load, then a check against real material.
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.
Zero. The belt runs empty at its normal speed while the unit averages the empty belt load over a set length of belt, counted in speed sensor pulses rather than seconds. Each test covers at least three full belt revolutions and at least six minutes, which averages out a belt that isn’t uniform. The belt must be clean and settled first, or you’re teaching the scale that a dirty belt is normal.
Span. A known load, supplied one of three ways. The electronic method, R-Cal, unbalances the load cell bridge with a precision resistor, so the unit sees a simulated load with nothing on the frame. Test weights hang a known static weight on the weighbridge, and a calibrated chain lays a known weight per unit length along the belt. A simulated load proves the electronics and the constants but nothing about the mechanics, which is why a chain or material check still matters. The manual itself names a material test as the best calibration method. See test weights, calibration chains or a material test.
The numbers. At commissioning, the first R-Cal should come in under about 0.75%; more than that means something needs finding first. On routine checks the manual allows 0.5% on a 9101 and 0.25% on a 9201. We work to 0.25% on both, and repeat span runs should agree within about 0.1%.
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. Site can check the span too, but record the result rather than accepting it, and call us if it has moved; the manual says the same. A scale that can’t repeat has a problem no adjustment will fix. We recommend a service calibration every quarter, so the scale keeps up with the changing seasons. See zero, span and repeatability explained.
Why does the zero or span move on a Micro-Tech?
The zero moves because the empty belt changed; the span normally only moves when something mechanical or electrical changed underneath it. Build-up, carryback, a dragging idler, a stiff tie rod or moisture in a junction box will all walk the zero, and auto zero tracking hides the early part of it. A span that has moved while the zero was held steady is a stronger signal: suspect the load cells, the cabling, the test weights or the frame geometry. See common belt weigher faults.
What speed sensor and load cell points matter on this integrator?
Two things catch people: the minimum pulse rate on the speed side, and the sense wiring on the load cell side.
Speed. The two speed inputs are optically isolated and powered from the unit’s own supply. The number that matters on site is the pulse rate: the manufacturer’s minimum is 1,000 pulses per minute at normal belt speed, and we recommend about 2,000. Fall under that on a slow conveyor with a low pulse per revolution sensor and you get coarse resolution and odd calibration behaviour with nothing visibly broken. See the belt weigher speed sensors guide.
Load cells. Up to six 350 ohm cells run in parallel, and cell sensitivity is selectable, so the unit must be told what is connected. Cable length is the trap: without sense leads the manufacturer allows about 61 metres of cable; with six-wire sense cable, about 914 metres. If the load cells aren’t wired into a junction box close by, run sense cable. The sense jumpers inside must match what is wired outside, or the scale reads off by a slow, temperature dependent amount. See the belt weigher load cells guide.
How does the Micro-Tech talk to the plant?
Through whichever outputs are fitted. An optional board gives a 4-20 mA output for rate, load or speed. On the digital side there’s a totaliser pulse for a remote counter, and an optional relay board adds status and alarm outputs. The serial port runs RS-232 or RS-485 with Modbus RTU, Allen-Bradley DF1 or Siemens 3964R; Ethernet carrying Modbus TCP and EtherNet/IP is built in, and Profibus DP is a plug-in board. If a remote counter drifts from the integrator’s total, check the weight each pulse represents. See getting belt weigher data into your PLC or SCADA.
Need a manual for your equipment?
Check which manual you’re holding. A 9101 manual gives the wrong routine span limit for a 9201, and the manuals are written in imperial units while the display can be set to metric, so check which your unit is set to before trusting a figure.
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.
We don’t publish access codes for this or any other integrator. If you’re locked out of yours, see locked out of your integrator?
When should you call us rather than keep resetting it?
Call when the alarm returns after a reset, because that is the unit saying the condition never went away. A Load Cell Fail, a cold start, a zero that will not settle after a proper clean, or a span outside the routine threshold all mean something physical needs finding. So does anything needing the enclosure opened. We service belt weighers, belt scales and weightometers across Australia on every major brand, so a mixed-brand plant is one visit, not a specialist per make. See booking a belt weigher service.
Frequently asked questions
Can you recover a Micro-Tech that has lost its setup after a cold start?
Usually, yes. If the settings were saved to USB or recorded somewhere, we reload them and re-calibrate. Where no record exists it becomes a full recommission measured off the frame.
Is an R-Cal check the same as a proper calibration?
No. It proves the load cell circuit, the converter and the calibration constants, but it cannot see build-up, a binding frame or a worn idler. Treat it as a check between visits, not a substitute for weights, a chain or a material comparison.
My integrator shows a low speed alarm but the belt is clearly running. What is it?
Almost always the speed sensor: a worn or seized wheel bearing, lost belt contact, a damaged cable, or a pulse rate below what the integrator needs. Get it looked at, because the tonnes are wrong the whole time it lasts.
How often should the zero and span be checked?
Site: a zero about every two weeks and after big weather changes, plus a span check that you record rather than accept. Us: a service calibration every quarter to keep up with the seasons. Where the tonnes are used for payment, the manufacturer suggests a daily zero and a weekly span check.
Do you work on the 9201 as well as the 9101?
Yes, and on the older Micro-Tech generations alongside them. Routine belt weigher calibration is practical maintenance work: we set the scale up correctly, prove it repeats, and record what we found and left.