DFE RFA User manual

INSTRUCTION MANUAL
Ribbon-Filament Transducer
Model RFA
DOC 801-0784 R4

Dover Flexo Electronics
307 Pickering Road
Rochester, NH 03867- 4630
U.S.A.
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©2022 Dover Flexo Electronics, Inc. All rights reserved. Dover Flexo Electronics has made reasonable effort to ensure accuracy of
this document. However, NO WARRANTY, whether expressed or implied, is given regarding the completeness or correctness of
information in this document. Dover Flexo Electronics shall not be liable for damages of any kind arising from the use or misuse of
this document. Dover Flexo Electronics reserves the right to make changes, additions, and deletions to this document without notice
and without obligation.

This label indicates: “Read The Manual”
Make sure you read and understand all instructions and safety precautions listed in this manual
before installing or operating your Model RFA Tension Transducer. If you have any questions
concerning the operation of your device or the information in this manual, please contact us.
Email: [email protected]
Telephone: [phone]
•Observe all warning labels.
•Never remove warning labels.
WARNING: During installation care should be taken not to drop the Model RFA
transducer, handle the unit with care, sudden jolts or drops can damage its components
and serious injury could result.
WARNING: If this equipment is not connected or operated in the manner specified, the
operating safety of this unit or of connected equipment cannot be guaranteed.
WARNING: Do not connect a standard excitation (5V) tension transducer to a DFE
amplifier with the Extended Range (XRE) option enabled (10V), the transducer may be
damaged.

Table of Contents
DOCUMENT CONVENTIONS ................................................................................................... 5
1GENERAL DESCRIPTION ................................................................................................. 6
1.1 CONSTRUCTION AND MECHANICAL OPERATION (see Figure 1)........................... 6
1.2 SPECIFICATIONS....................................................................................................... 7
1.3 STANDARD FEATURES ............................................................................................. 7
1.4 CONFIGURATION CHOICES...................................................................................... 7
1.5 OPTIONS .................................................................................................................... 8
2INSTALLATION.................................................................................................................. 9
2.1 DIMENSIONS .............................................................................................................. 9
2.2 PRE-INSTALLATION REQUIREMENTS ....................................................................10
2.3 INSTALLATION ..........................................................................................................11
2.4 ELECTRICAL OPERATION........................................................................................12
3CALIBRATION AND SETUP.............................................................................................13
3.1 INTRODUCTION ........................................................................................................13
3.2 ZERO THE TENSION METER....................................................................................13
3.3 CALIBRATE THE TENSION METER..........................................................................13
4CARE AND MAINTENANCE.............................................................................................14
4.1 BEARING LIFE ...........................................................................................................14
4.2 DISASSEMBLY AND REASSEMBLY - TOOLS REQUIRED ......................................14
4.3 CHANGING THE BEARING(S) AND/OR WHEEL.......................................................14
5TROUBLESHOOTING.......................................................................................................15
APPENDIX A: SELECTION OF LOAD RATING ......................................................................17
APPENDIX B: TYPICAL TENSIONS FOR VARIOUS MATERIALS.........................................19
TERMS AND CONDITIONS OF SALE AND SHIPMENT .........................................................20

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DOCUMENT CONVENTIONS
NOTES - Highlight important concepts, decisions you must make, or the implications of those
decisions.
CAUTIONS - Tell you when equipment may be damaged if the procedure is not followed
properly.
WARNINGS - Tell you when people may be injured, or equipment may be damaged if the
procedure is not followed properly.
Numbered lists indicate tasks that should be carried out in sequence:
1. First do this
2. Then do this

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1 GENERAL DESCRIPTION
The Model RFA “Ribbon-Filament” Tension Transducer is an electro-mechanical device that converts ribbon,
web, or filament tension into a DC voltage proportional to tension. The voltage is amplified in external electronic
circuitry such as a DFE Tension Amplifier, Indicator or Closed-Loop Controller which is calibrated to output and/or
display actual tension. The tension reading is expressed in pounds, ounces, grams, kilograms, newtons, or any
other desirable units. It can also be supplied to a regulator circuit to control tension automatically.
The RFA Tension Transducer is typically used in applications where the machine has only one side frame and
the idler wheels are cantilevered. The information in this section will help give a clear understanding of the RFA
Tension Transducer system - how it works and how it’s used.
1.1 CONSTRUCTION AND MECHANICAL OPERATION (SEE FIGURE 1)
The standard RFA Transducer wheels are manufactured of aluminum to be lightweight and of low inertia,
and the ribbon wheels and filament wheels are given a hard coat anodized surface finish to be durable.
The bearings are standard deep-groove ball type with shields to discourage entry of contaminants.
Custom wheel geometries and/or finishes are available including those made by the customer to be
mounted on the adapter wheel, subject to specific DFE engineering approval.
Inside the transducer is a single beam having two parallel cantilevered webs with strain gages mounted
on each. When tension is applied, the beam deflects a small amount, causing an electrical output from
the strain gages which is directly proportional to the filament tension.
The bore of the housing acts as a mechanical stop, preventing damage to the beam and gages from
accidental overloads. The stop is functional through 360 degrees, so the overload condition may occur
from any direction, not just the load direction. In all cases, the beam is prevented from deflecting far
enough to cause any damage.
Figure 1 - CUT-AWAY VIEW OF RFA TRANSDUCER

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1.2 SPECIFICATIONS
ELECTRICAL SPECIFICATIONS
Excitation Voltage: 5 VDC max (Std), 10 VDC max (XR Option)
Output: 100 mV/V, nominal
Strain Gages: Semiconductor, 100 ohms nominal resistance
Repeatability: +/- 1/4% FS
Linearity and Hysteresis Combined: +/- 1/2% FS
Temperature Range: -10° F to +200° F (-23° C to +93° C)
Temperature Coefficient: 0.02% per degree F, typical (0.01% per degree C, typical)
Electrical Connector: MIL Spec - PT02E10-6P
Electrical Connections:
Pin A (White): Signal Output (-)
Pin B (Black): Excitation (+)
Pin C (Red):Excitation (-)
Pin D (Green):Signal Output (+)
Pin E (Blue): Excitation (-)
Pin F (Brown): Excitation (+)
Mating Electrical Connector:
MIL Spec (Standard) - 6 socket, female, PT06E10-6S
MECHANICAL SPECIFICATIONS
Materials: 303 stainless steel and 7075-T6 aluminum, black anodized hard coat wheel finish.
Maximum Overload Capacity: Four times the load rating.
Deflection: .005" typical (0.127 mm typical)
Standard Connector Position:
S, FL styles - 6 o'clock
PB style - Rear with reference to force direction
Load Ratings: 10, 25, 50, 100, 150 (45, 111, 222, 445, 670 N)
Note: The information below is only applicable if a DFE Wheel or shaft assembly is used.
Break-Away Torque: 0.25 in-oz (18 gram-cm) typical
Basic Dynamic Load Rating of Bearings: 4300 lbs (19120 N)
Wheel Weights:
Filament 0.49 lbs (222 g)
Ribbon 0.45 lbs (204 g)
Adapter 0.65 lbs (295 g)
1.3 STANDARD FEATURES
Dual Cantilever Beam: Provides high strength and accuracy at low tension.
Stainless Steel and Aluminum Construction: Excellent durability and corrosion resistance.
Compact Size: For easy mounting--even in small spaces.
1.4 CONFIGURATION CHOICES
These are explanations of standard choices of various configurations that were specified for your
application.
Mounting Styles: Screw or Bolt mount (S) uses a single bolt to mount to machine frame. Pillow Block
bracket (PB) uses a right-angle bracket to mount onto the machine frame. Flange mount (FL) uses a

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four-bolt flange mounted onto the machine frame which can be rotated to any position for precise
orientation.
Load Ratings:10, 25, 50, 100, 150 lbs (45, 111, 222, 445, 670 N)
DFE Wheel Types: Ribbon Wheel (specify width of 1 to 4 inches), Filament Wheel, Adapter Wheel (hub
for custom applications).
Connector Positions:
S, FL: 1:30, 3:00, 4:30, 6:00 (std.), 7:30, 9:00, 10:30, 12:00.
PB: Rear (std.), 1:30, 3:00, 9:00, 10:30, 12:00 with reference to force direction.
1.5 OPTIONS
Extended Range (XR): Accepts 10V excitation from a supported amplifier, indicator, or controller with
(XRE) option.
Metric Mounting Screw (MMS): Metric mounting thread for S type transducers.

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2 INSTALLATION
2.1 DIMENSIONS
Figure 2 – DIMENSIONS

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2.2 PRE-INSTALLATION REQUIREMENTS
Note: No brakes, clutches, belts, chains, or gears should be attached to the transducer
wheel. It cannot be a nip roll or be in contact with a nip wheel. Nothing must contact the wheel except
the ribbon or filament.
1. TENSION ZONE
The transducer must be located in the tension zone which is to be monitored or controlled. The
beginning or end of any tension zone is always at a nip (driven or braked), unwind shaft, rewind
shaft, or drag bar. Any element in the filament path that can change tension is at one end of a tension
zone.
Figure 3- TENSION ZONES
2. WRAP ANGLE
The web or filament must always contact the transducer wheel in the same way. The wrap angle
must not change as the unwind or rewind reel diameter changes. Therefore, there must be at least
one idler wheel between the transducer and the unwind or rewind shaft. If the machine has more
than one web path, be sure to choose a location that is wrapped the same for each. Otherwise, it will
be necessary to install an additional idler roll or transducer, or dual calibration circuitry, or all three. If
the wrap angle is allowed to change, the transducer output will change with angle as well as tension,
and accuracy will be reduced.
3. MOUNTING SURFACE
The structure on which the transducers are mounted must be very stable and strong. Any
movement of the structure may be sensed by the transducers and may cause inaccurate tension
readings. The surfaces must also be smooth and flat so the transducers can be properly aligned
during installation. The RFA Transducer is sold in three different mounting styles and attached to the
machine frame by one of three methods: A single bolt (S) through the back of the unit, a four-bolt
flange (FL), or a pillow-block type bracket (PB).
Figure 4 – RFA MOUNTING STYLES