Gauge head - PMGG123
Contact-free measurement and a robust design makes the Millmate Thickness Gauge will provide high availability and hassle-free operation in harsh industrial environment.
Gauge head overview
The gauge head has no fragile parts or parts that will age. Therefore the MTG provides a superior long-term stability. From a maintenance point of view the system is the most dependable thickness gauge on the market.
An aluminium-bronze housing is used as a case for the measuring coils and the electronics.
The measured thickness deviation and other signals from the gauge are transferred to a control unit via fieldbus communication.
Only a few certified plates (included in delivery) are needed to calibrate the system to cover the complete measuring range. After calibration at commissioning, the system measures any non-ferrous material or alloy without additional calibration.
Application
The heavy-duty design of the gauge head and the stability of the measuring principle makes the Millmate Thickness Gauging System superior in applications that previously were considered impossible. Measurement can be done close to the rollgap, without removal of emulsion.
Material
The MTG is designed for dependapble gauge measurement on a wide range of non-ferrous materials with different alloy compositions and resistivities, i.e. aluminium, copper, zinc, tin, lead and beryllium.
Single or Double gauge system
In reversing mills it is very common to use thickness gauges on both sides of the mill. The MTG system offers two different contol units, one for handling a single gauge and the other for handling two gauges. The user-friendly operator unit has a display function for double gauge configuration. The operator can see the thickness gauge deviation graphs, one for each gauge, on the same menu page. The feature with double gauge systems can also be valuable in applications like tandem mills or slitting lines.
Options
Sledge
<p>The gauge holder is mounted on a sledge that enables the gauge to move horizontally into the measuring position. ABB offers a standard sledge solution with a number of stroke lengths. Strip width (min./max.) determines what kind of sledge should be used. Consult your local ABB representative for further details.</p>Enhanced protection kit
<p>In applications where the gauge may be exposed to severe strip breaks, other high impact forces, or fires, the optional enhanced protection kit is recommended.The enhanced protection kit consists of a stainless steel hose and hood for the gauge and the gauge holder. The kit enhances the mechanical, chemical, and fire protection of the gauge.</p>Clad measurement function
<p>With the optional clad measurement function the Millmate Thickness Gauging system measures the thickness of multi-layer aluminium clad strip, this with superior accuracy.<br> The built-in clad function only requires information about the clad layers' nominal thicknesses and resistivities. The resistivities can be determined with support functions included in the scope of supply. The start-up and commissioning routines for the clad function are straightforward and easy to use. The need for test plates is limited. New types of clad material can easily be added, without the need for time-consuming test and calibration procedures.</p>Resistivity measurement function
<p>With the optional resistivity measurement function, the Millmate Thickness Gauging system offers a unique possibility to continuously monitor material property changes.<br> Material property measurement on metal strip are normally done in laboratory according to a spot test procedure. The MTG, with built-in resistivity function, measures the resistivity on-line with an accuracy equal to the best available lab instruments.</p>Pulsed Eddy Current technology
<p>The Millmate Thickness Gauging system is based on the Pulsed Eddy Current technology, which uses magnetic fields for measurement of the strip thickness. The interaction between an applied magnetic field and the electrically conductive strip indicates the thickness - without influence from material composition or conditions in the measuring gap.</p>
Phase 1: Transmitting
<ul> <li>An electric field is generated with a transmitting coil</li> <li>The field is applied until it fully penetrates the strip</li> <li>The field "energy" is stored in the air gap and in the strip</li> <li>The amount of energy stored in the strip depends on the thickness alone - not on resistivity</li> </ul>Phase 2: Distance measurement
<ul> <li>Fast air response just after transmit field is swithed off</li> <li>The measurement of air gap energy corresponds to distance between coil and strip</li> <li>Pulse time t1 is typically less than 5μs</li> </ul>Phase 3: Resistivity measurement
<ul> <li>Response from the surface area of the strip</li> <li>The measurement starts when the air gap signal has declined</li> <li>The measurement of the surface response corresponds to resistivity and is dependent on the speed of the field leakage out of the strip</li> </ul>Response from the whole strip
<ul> <li>The measurement starts when the air gap signal has declined (phase 3 is included in phase 4)</li> <li>The measurement of the whole strip corresponds to the complete energy stored in the strip, and continues until the strip response has almost declined (t3)</li> <li>The measurement corresponds to the strip thickness</li> <li>The resistivity does not affect the level of the whole strip response</li> <li>The tail part after t3 is calculated with the use of the resistivity part</li> </ul>Product Data
| Type | PMGG 123-S | PMGG 123-F |
| Min. thickness | ||
| for low alloyed copper and aluminum | 0.010 mm (foil mode) | 0.010 mm (foil mode) |
| 0.025 mm | 0.025 mm | |
| for high resistivity material (450 nΩm) | 0.040 mm (foil mode) | 0.040 mm (foil mode) |
| 0.100 | 0.100 | |
| Max. thickness | 15mm | 6mm |
| Repeatability | ±0.03% (not better than 0.3 μm) | ±0.03% (not better than 0.3 μm) |
| Total Accuracy (relative permeability=1.0) | Non-ferrous metals | Non-ferrous metals |
| strip thickness > 2.0 mm | ±(0.05% + 2 μm) | ±(0.05% + 1.5 μm) |
| strip thickness < 2.0 mm | ±(0.1% + 1 μm) | ±(0.1% + 0.5 μm) |
| Min. strip width | 250 mm | 140 mm |
| Strip position | ||
| for changes faster than 1 mm/s | ±5 mm | ±3 mm |
| for changes slower than 1 mm/s | ±10 mm | ±8 mm |
| Strip slope | ±3° | ±3° |
| Step response | 15 ms | 15 ms |
| Operation temperature | +5 - +55°C | +5 - +55°C |
| Degree of protection | IP 65 | IP 65 |
Power supply (from the control unit) |
24 V DC, max. 3 A | 24 V DC, max. 3 A |
| Dimensions (W x D x H) | ||
| Gauge without holder | 198 x 425 x 302 mm | 160 x 425 x 293 mm |
| Weight | ||
| Gauge | 50 kg | 37 kg |
| Gauge holder | 30 kg | 30 kg |