ABB Millmate Rolling Force Measurement and Control System On site Troubleshooting and Maintenance Guide

Calculation formula:

L×W×zero point zero zero zero one=F nom (MN)

L×W×0.0001=F nom(MN)

Where L is the length (mm) and W is the width (mm). For example, if the rated load is 14MN and the given width is 370mm, the required length L=14/(0.0001 × 370) ≈ 378mm, rounded upwards to 390mm (multiples of 30mm).

Replacement reminder: Rectangular sensors are usually integrated into the Load Cell Package, which includes a lower pressure plate, sensor frame, and upper pressure plate. It is recommended to replace the pre tightening force pack as a whole during replacement to ensure even force distribution and easy installation.

2.3 Circular Sensor PFVL 141R

Installation position: between the rolling mill nut and the frame, suitable for situations where there is insufficient space under the grinder screw and bearing seat.

Features: Stainless steel laminated winding, outer stainless steel ring protection. The standard specifications cover 2.0 MN to 28 MN. The size parameters D2 (inner diameter) and D3 (outer diameter) are the key to selection.

Size and load correspondence (excerpt):

Rated load (MN) D2 (mm) D3 (mm) 2 sensors Maximum cable length (m)

2.0 100 200 30

6.3 285 420 25

10 385 525 24

16 480 660 22

28 620 850 17

2.4 Small circular sensor QGPR 104/102

Application: Suitable for situations where the space is extremely small or the load is less than 2MN, such as steel pipe rolling mills and small vertical rolling mills. Covering 0.1 MN to 2.5 MN. QGPR 104 is used for 0.1~0.63 MN, and QGPR 102 is used for 1.0~2.5 MN.

Replacement precautions: The matching device for the QGPR series is QIPZ 127, which is not compatible with the PFVO 142/143 used in the PFVL series. The controller model also needs to be matched: PFVA 401 series is used for PFVL, PFXA 401 series is used for QGPR.

Chapter 3 Common Fault Phenomena and On site Diagnosis

3.1 No rolling force signal or abnormally low signal

Phenomenon: The operator station displays a rolling force of 0 or much lower than the normal value, and it does not change with the rolling process.

Possible reasons:

Matching unit or sensor cable disconnection: Any disconnection in the circuit from the sensor to the matching unit and then to the controller.

Controller channel damage: Corresponding analog input channel failure.

Internal coil circuit of sensor: caused by overheating or mechanical shock.

Diagnostic steps:

Check the indicator lights on the matching unit. During normal operation, there should be a power indicator (usually a green LED).

Measure the resistance of the sensor coil (primary and secondary) with a multimeter. The resistance value of PFVL series is generally several tens of ohms. If it is infinite, it will break internally.

Check the 'Load Cell Test' function in the diagnostic menu of the controller. This function can individually activate each sensor and display the original signal value. If a channel displays 0 or close to 0, the sensor wiring can be exchanged to confirm whether it is a sensor or channel issue.

Check the controller's self diagnostics. If the message 'Transformer test failed' is reported, it indicates a sensor or matching unit malfunction.

3.2 Rolling force signal jumping or unstable

Phenomenon: The displayed rolling force value fluctuates up and down, and there is significant noise even when the rolling mill is unloaded.

Possible reasons:

Poor grounding or electromagnetic interference: The shielding layer is not grounded at one end or is parallel to high current cables.

Mechanical looseness: The sensor installation pressure plate is not tightly pressed, or the gap between the rolling mill window is too large, causing the sensor to bear lateral force.

The filtering time of the matching unit or controller is set too short.

Diagnostic steps:

Observe the analog output of the controller (0~± 10V or 4~20mA) with an oscilloscope, and check the noise frequency and amplitude. If it is high-frequency noise, focus on checking the shielding grounding.

Enter the controller parameter menu and increase the filter time (which can be increased from the default value to 2000ms) to observe the improvement in stability.

Check the mechanical clearance of the rolling mill. Connect the sensor signal to diagnostic mode, load it with a jack or pressure head when unloaded, and observe whether the signal is linear and whether there is any jumping. If there is a step like change in the signal during loading, it indicates poor contact between the internal coil or matching unit of the sensor.

3.3 Severe zero drift

Phenomenon: When there is no load, the displayed value is not zero and slowly changes with temperature or time.

Possible reasons:

Temperature compensation failure: The original sensor had temperature compensation components inside, which drifted after long-term aging.

The sensor is subjected to excessive lateral or torsional forces, resulting in residual stress.

Controller zero setting error or drift.

handle:

First, perform the "zero calibration" function of the controller (usually in the menu of Operator Unit 410). Perform zero point adjustment in an unloaded state.

If the zero point is still unstable, check if the sensor installation is tilted. Measure the upper and lower contact surfaces of the pressure plate and sensor with a spirit level, allowing for a tilt of ≤ 0.1mm/m.