The horizontal load cell senses the web tension’s (T) horizontal component (FR); not the vertical force (FV).
In this scenario, the measurement force (FR) is a function of only the tension in the web (T) and the web angles (α and β). Since the tare force (the weight of the deflector roll and bearings) will not be measured, it can be very large compared to the web tension without affecting the accuracy of the tension measurement.
Specifying the load cell
Since load cells are typically used at both ends of a roll, rating the individual cell is usually based on half of the resultant force. The ideal load cell size is usually the smallest nominal capacity rating accommodating that force level, so long as the force exceeds 10 % of the nominal load. Before choosing a larger size, however, consider using the extended range feature of ABB load cells. And always verify that overload specifications will not be exceeded in either direction.
Application hint Two 10 % application guidelines are useful in selecting load cell sizes:
The proportion of web tension that is actually sensed by the load cell should be at least 10 % of total web tension. For operational conditions producing values below 10 %, consult ABB.
2. During normal operation, the sensed force should not be less than 10 % of the load cell’s capacity
PFTL 101 Horizontal force measurement, 0.5 to 20 kN
PFTL 101A/AE/AER PFTL 101B/BE/BER
PFTL 201 Horizontal force measurement, 10 to 100 kN
PFTL 201C/CE PFTL 201D/DE
PFCL 201 Vertical force measurement, 5 to 50 kN
PFCL 201C/CD/CE
PFEA – the compact solution
All three versions have multi-language digital display and configuration keys. The configuration keys being used for setting different parameters and to check the status of the tension system. The 2 x 16 character display can present sum, difference or individual load cell signals. All three versions are available in both DIN-rail version and enclosed IP65 1 version for mounting in more severe environments.
PFEA 111
A cost effective, compact and user-friendly tension electronics providing an accurate and reliable fast analog SUM signal from two load cells for control and/or monitoring. The display can show the SUM, individual A & B and difference signal. The small size and DIN-rail mount make this unit very easy to integrate into many types of electrical cabinets.
