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

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

In modern steel rolling production, accurate measurement of rolling force is the core link to ensure plate thickness tolerance, optimize roll gap setting, monitor the status of support roll bearings, and compensate for roll eccentricity. ABB's Millmate rolling force measurement system is based on the classic Presductor ® The principle of magneto elasticity, patented in 1954, has become the industry benchmark for cold and hot rolling mills worldwide due to its durability, high overload capacity, and excellent signal-to-noise ratio. The system mainly consists of Millmate Controller 400 (MC 400) controller, matching unit (PFVO 142/143 or QIPZ 127), and force sensors installed in the rolling mill.

However, even such a reliable system, after years of operation in harsh environments such as high temperature, high humidity, vibration, and dust, can still experience problems such as signal abnormalities, zero drift, and even sensor failure. When the original model is facing production stoppage or the spare parts procurement cycle is too long, engineers often need to complete fault diagnosis, model confirmation, and precise replacement in a very short time. This article is based on official technical information from ABB, combined with on-site maintenance experience, to provide a detailed breakdown of common fault phenomena, diagnostic steps, sensor selection and replacement process, and controller parameter debugging methods for the Millmate rolling force system. It provides a "hands-on" operation guide for maintenance personnel in steel rolling production lines.

Chapter 1 Core Technology Review: Presductor ® Magneto elastic principle

The core of Millmate rolling force sensor is Presductor ® Technology utilizes the magneto elastic effect of ferromagnetic materials - when mechanical stress is applied to the material, its magnetic permeability changes. There are four holes in the sensor body, which are respectively wound with primary coils (excitation) and secondary coils (measurement) that are perpendicular to each other. When there is no load, the magnetic flux of the two coils is orthogonal, and there is no induced voltage in the secondary; After loading, the magnetic permeability in the stress direction decreases, the magnetic permeability in the vertical direction increases, the magnetic field lines deflect, and the secondary coil induces a voltage proportional to the load.

Key performance advantages:

High overload capacity: The maximum allowable load can reach 700% of the rated value without mechanical damage; Performance data will not permanently change under 300% load. This ensures that even in the event of abnormal working conditions such as steel jamming or overlapping, the sensors of the rolling mill remain reliable.

High signal-to-noise ratio: The sensor output signal can reach up to 500mV/V, far higher than traditional strain gauges, and is extremely insensitive to insulation defects (the measurement accuracy can still be maintained even when the insulation resistance drops to 10k Ω).

No preload requirement: Unlike pressure magnetic sensors, Presductor can obtain reliable signals without applying preload, simplifying installation.

Redundant design: Each standard sensor contains 1500-2000 independent magneto elastic units, which can output the true average force value even if there is uneven local force.

Chapter 2 Identification and Selection Replacement of Force Sensor Models

There are four series of Millmate rolling force sensors, corresponding to different installation positions and load ranges. When facing sensor damage or discontinuation for replacement, it is necessary to accurately identify the prototype number and select a suitable substitute.

2.1 Circular Sensor PFVL 141C

Installation position: Under the mill screw or hydraulic cylinder, above the bearing seat of the upper support roller.

Features: Made from square steel billets, with stainless steel shrink rings on the outer side to protect the coil. The core diameter is based on a module of 30mm, with a total of 23 standard specifications covering 2.0 MN to 60 MN. It is suitable for rolling mill windows with ample space.

Size and load correspondence (excerpt):

Rated load (MN) Inner diameter ID (mm) Outer diameter OD (mm) 2 sensors Maximum cable length (m)

1.6 150 210 30

5.0 270 320 28

10 360 410 24

20 510 560 22

40 720 800 13

60 810 890 10

Replacement point: When selecting the rated load, take the next standard value that is not less than the original load. For example, if the original sensor is 18MN, the 20MN specification should be selected. Note that the outer/inner diameter must match the original installation flange, otherwise mechanical modification is required.

2.2 Rectangular sensor PFVL 141V

Installation position: Below the bearing seat of the lower support roll, there should be a sufficiently large flat surface for the lower crossbeam of the rolling mill.

Features: The length and width are measured in modules of 30mm, and when the length exceeds 900mm, it is measured in modules of 60mm. Covering 0.63 MN to 60 MN. There is no fixed size chart, and it needs to be calculated based on the required load and installation space.