Replace an analogue amplifier
The existing force sensors and roller may remain useful, but the potentiometer-adjusted electronics are difficult to set up, document or support.
Likely path: compatibility audit → EMGZ309 family
Choose the commercial scope
What are you actually trying to replace or improve?
A “bad tension reading” is not automatically a failed load cell. The problem may be mechanical loading, wiring, signal electronics, calibration, PLC scaling, the actuator, or the process itself. Define the desired outcome before changing parts.
Add a new tension station
The machine has no direct force measurement, or the current signal is inferred from brake pressure, dancer position or drive current.
Likely path: roller geometry → sensor family → electronicsModernize PLC connectivity
The plant needs a stable analog value, left/right data, recipes, configuration access, or EtherNet/IP, PROFINET or EtherCAT integration.
Likely path: I/O narrative → model-specific interfaceAutomatically control tension
The project must regulate an unwind brake, unwind or rewind drive, or intermediate section—not simply show a number.
Likely path: force sensors → CMGZ controller → actuator reviewPlain-language system architecture
Five layers turn a moving web into a useful tension signal
A junior engineer should be able to trace the system from the material to the machine action. If one layer is missing or misunderstood, changing the amplifier may not solve the production problem.
Moving webMaterial, width, speed and actual pulling force
Measuring rollerEntry angle, exit angle, wrap and roller weight
Force sensorMechanical load becomes a millivolt signal
ElectronicsAmplify, scale, display or communicate the signal
Machine actionMonitor, alarm, trend, or regulate a brake or drive
“Web tension” and “sensor force” are not the same number
The web changes direction around the measuring roller. That geometry creates a resultant force at the roller supports. For a simple symmetrical deflection, a preliminary reference is 2 × tension × sin(wrap angle ÷ 2), before accounting for roller weight, force direction, acceleration and the number of sensors. Final sizing uses the actual machine geometry.
An amplifier is not a closed-loop controller
A measuring amplifier conditions the load-cell signal and sends a usable value to a display or PLC. Automatic correction additionally needs a controller, a brake or drive that can influence tension, safe machine authority, interlocks, limits, tuning and a defined fallback state.
Start with the roller mechanics
Select the force-sensor architecture before the electronics
FMS offers force-measuring bearings, blocks and complete measuring rollers for different machine constructions. A visually similar sensor is not automatically a mechanical or electrical replacement.
Live shaftCompact
A-Series force-measuring bearings
A compact aluminum force sensor for continuous-material lines using a rotating live-shaft idler. FMS publishes a 30:1 measuring range, ±0.5% accuracy class, nominal forces from 50 to 1,000 N and overload protection up to ten times nominal force.
Strong fitSmall-to-medium forces with restricted installation space
Confirm17 mm shaft direction, bearings, roller mass, speed and environment
Dead shaftFlexible mounting
CA-Series force sensors
Compact stainless-steel force sensors for dead-shaft idlers. FMS publishes nominal force ratings from 50 to 1,500 N, a 30:1 measuring range, ±0.5% accuracy class, multiple metric and imperial adapter diameters, and high-temperature or vacuum options.
Strong fitFixed shaft with rotating outer roll and compact mounting
ConfirmJournal/adapter, mounting face, force direction, option and environment
CantileverOne-sided access
RMGZ9 measuring rollers
A complete cantilever force sensor and measuring roller for compact one-sided installations. FMS publishes nominal forces from 50 to 1,000 N, a 30:1 measuring range, ±0.5% accuracy class and overload protection up to ten times nominal force.
Strong fitCompact web path with one-sided service access
ConfirmRoll face, diameter, coating, orientation, speed and force
| Roller or machine architecture | Preliminary FMS family direction | What still controls the selection |
|---|---|---|
| Live-shaft idler | LMGZ or LMGZD force-measuring bearings | Shaft size, bearing arrangement, force direction, roller weight, operating range and precision need |
| Dead-shaft idler | A-, CA-, F- or FA-Series direction | Journal and adapter geometry, stationary shaft, shell bearings, space, nominal force and environment |
| External pillow blocks | UMGZ; UMGZP for defined PR 9951 replacement; application-specific sealed families | Bolt pattern, bearing size, horizontal/vertical loading, environment, temperature and replacement identity |
| Cantilever station | RMGZ9 or compact RMGZ9M direction | One-sided mounting, face length, diameter, coating, orientation, speed and access |
| Complete measuring roller | IMGZ direction | Roll length, diameter, shaft interface, web position, nominal force, balance and line speed |
| Individual wire or strand pulley | RMGZ100/200/300/400/800 and telemetry paths | Stationary versus rotating machine, pulley, strand count, speed, centrifugal effects and data transmission; use the wire & cable tension path |
Common naming: processors often search for “web tension load cells.” FMS generally uses “force sensor,” “force-measuring bearing,” “force-measuring block,” or “measuring roller.” The correct term follows the machine construction—not the phrase on the purchase request.
Signal conditioning, data and regulation
Choose the electronics around the retained sensor and required machine output
Do not assume that a modern display, a current output and an industrial-network interface are interchangeable. Identify sensor feedback, channel count, housing, power, analog scaling, PLC protocol and whether the system only measures or also controls.
Analogue amplifier modernization
EMGZ309
FMS positions the single-channel EMGZ309 as a plug-and-play replacement for analogue potentiometer-adjusted units and for use with FMS force sensors. It supports setup from the three-key display or a web browser.
- One channel; one or two force sensors
- Published 1 ms processor cycle
- 0–10 V and 0/4–20 mA outputs on the standard family
- DIN-rail, wall and panel-mount directions are published
“Plug and play” still needs a check: confirm the existing sensor, terminals, feedback signal, power, output scaling, housing, cable, calibration and any machine logic before replacement.
Official EMGZ309 details ↗
Compact setup & commissioning evidence
EMGZ310.ComACT
A compact digital strain-gauge amplifier with three-key/LCD setup and optional operation through the free FMS-ComACT app. The app can display sensor feedback, log and export short data records, and save configuration settings.
- One channel; one or two force sensors
- Published 14-bit resolution and 1 ms cycle time
- ±10 V and 0/4–20 mA output paths
- Standard and V05 sensor-feedback variants; DIN or wall mounting
Useful for commissioning: configuration records and short signal logs can improve evidence. They do not replace a machine historian, safety system or full production-data platform.
Official EMGZ310.ComACT details ↗
Closed-loop regulation
CMGZ309 and CMGZ309.EIP
When the project must regulate an unwind brake, unwind or rewind drive, or intermediate driven section, a tension controller compares measured tension with the target and commands a compatible actuator. The EtherNet/IP version adds a reviewed machine-network path.
- Force sensors normally connect directly to the controller
- A separate EMGZ amplifier is not normally required for the same control zone
- Actuator type, command signal, roll diameter behavior and tuning matter
- Limits, interlocks, manual mode and safe fallback remain machine responsibilities
Left/right visibility and industrial networks
Use the model family that matches the data architecture
EMGZ321 measures the two sides of a roller independently so the machine can see left/right load distribution rather than only one combined value. FMS also publishes single- and dual-channel amplifier families for EtherNet/IP, PROFINET IO and EtherCAT. Select the protocol, channel count and input variant deliberately; do not treat a web-browser setup port as a plant fieldbus.
Controls boundary: document the PLC manufacturer, protocol, scanner/master ownership, requested update rate, cyclic data, parameters, alarms, units, scaling, byte order, network security and loss-of-communications behavior before quotation.
Retain useful hardware only after proving what it is and how it behaves
A practical retrofit may keep the roller and force sensors, replace only the electronics, replace the complete measuring station, or add automatic control. The least expensive hardware change is not automatically the lowest-risk project.
- Photograph every nameplate, terminal and roller end
- Trace the existing sensor cable and excitation path
- Record zero, loaded signal, direction and output scaling
- Define what the PLC, HMI, alarm or actuator does with the value
- Preserve drawings, parameters, calibration and backups before removal
Do not bypass safeguards to gather data. Electrical testing, mechanical loading, calibration and machine operation must follow plant procedures and be performed by appropriately qualified personnel.
Freeze the installed configuration
Capture manufacturer, model, serial, sensor count, mounting, wiring, power, outputs, PLC scaling, drawings, parameter settings and known modifications.
Define the required production outcome
State whether the plant needs restored monitoring, better repeatability, left/right visibility, network data, records, alarms or automatic control.
Calculate the actual sensor loading
Use entry and exit angles, wrap, minimum and maximum web tension, roller weight, force direction, dynamics and number of sensors.
Choose retained and replaced layers
Confirm mechanical fit, sensor health, amplifier input, outputs, housing, network, controller and actuator instead of assuming a part-number substitution.
Write the installation and acceptance plan
Assign mechanical, electrical, PLC, network, safety, calibration, startup, tuning, training, documentation and performance-test responsibilities.
Mechanical compatibility
Mounting dimensions, shaft and bearing construction, roll face, force direction, nominal load, overloads, alignment, balance, speed, environment and service access must match.
Electrical compatibility
Sensor feedback range, bridge and excitation, connector, cable, shielding, amplifier input, power, analog range, polarity, scaling and grounding must be reviewed.
Control compatibility
PLC protocol, update rate, program ownership, brake or drive command, actuator authority, interlocks, manual mode, limits, communications loss and safe state must be defined.
Application-first scope
One measurement architecture supports many continuous-material processes
The material name does not select the sensor by itself. Machine mechanics, running force, environment, signal use and control objective still govern the system.
Cast film, blown-film downstream & sheet lines
Measure through haul-off, treatment, coating, slitting and winding zones; relate tension to wrinkles, stretching, tracking and roll formation.
Battery, adhesive, release liner & technical webs
Keep force data separate from coating weight while using it to understand registration, dryer transport, lamination, slitting and winding behavior.
Labels, narrow web, flexographic & converting
Add direct tension feedback around unwind, registration, print, die-cut, lamination and rewind sections.
Paper, nonwoven, fabric & hygiene products
Choose sensor constructions for roller weight, wide operating ranges, moisture, temperature and demanding production environments.
Aluminum, steel, copper foil & process lines
Review high forces, heavy rollers, harsh environments, pillow-block arrangements and plant-specific controls standards.
Drawing, extrusion, spooling, stranding & cabling
Stationary pulley measurement and rotating strand-tension systems use different equipment paths. See the dedicated wire and cable architecture for telemetry and brake control.
Interactive web-handling selector
Narrow the force sensor, electronics and control path
Choose the machine goal, roller support, approximate force range, data connection and whether the line needs monitoring, automatic tension control, cross-web analysis or guiding.
Retrofit boundary: selector results are preliminary. Final replacement compatibility still requires the installed model, mounting, wiring, sensor feedback, actual load, output, PLC and machine-control review.
Prepare a useful review
Send the installed facts and the desired machine behavior
You do not need to diagnose the system before asking for help. A complete machine sketch, nameplate set and control objective are more useful than a request for “a load cell around 20 pounds.”
Show the measuring location and every load acting on it
- Machine type, material, width, thickness and line function
- Minimum, normal and maximum material tension with units
- Entry and exit angles or a dimensioned web-path sketch
- Roller construction: live shaft, dead shaft, pillow block, cantilever or complete roller
- Roll face, diameter, shaft or journal, bearings, roller weight and rotational speed
- Sensor quantity, mounting orientation, force direction, photos of both roller ends
- Temperature, moisture, washdown, chemicals, dust, hazardous area and protection needs
- Existing manufacturer, model, serial, nameplate, drawings and failure history
Define what should happen after the force is measured
- Existing sensor feedback, bridge, excitation, cable, connector and terminal information
- Current amplifier/controller, power, housing, analog output, scaling and calibration
- PLC/HMI platform and required EtherNet/IP, PROFINET, EtherCAT or analog interface
- Monitor, alarm, trend, recipe, left/right, reporting or historian requirements
- For control: unwind/rewind/intermediate zone, brake or drive, command and safeguards
- Equipment to retain, plant standards, panel space and cable route
- Shutdown window, installation responsibility, startup, tuning, training and acceptance test
- Budget phase, required-in-service date and future machine changes
Official FMS resources:
EMGZ309 ↗
EMGZ310.ComACT ↗
EMGZ321 ↗
A-Series ↗
CA-Series ↗
UMGZP ↗
FMS product index ↗
Connect the retrofit to the complete process
Related measurement, guiding and diagnostic systems
Tension is one layer of the production system. Thickness, coat weight, web position, cross-web tension profile and wire/cable telemetry answer different questions.
Sales & applications support—not an outsourced plant maintenance department
Gauge Advisor turns the machine need into a reviewable FMS equipment scope.
Gauge Advisor helps identify the application, collect drawings and operating inputs, narrow force sensors and electronics, coordinate final manufacturer review, and support commercial quotation and implementation planning. For an existing equipment fault, collect the model, serial, wiring, symptoms, alarms, photos and production impact so the request can be routed to the appropriate FMS resource. FMS owns manufacturer product-service, repair, maintenance and factory technical determinations.
Plant electrical work, mechanical repair, machine safety, lockout/tagout, PLC program changes, field labor, commissioning and acceptance responsibilities are performed only by the appropriately qualified and explicitly contracted parties.
Commercial and technical questions
Web tension load cell and amplifier retrofit FAQ
These answers establish a preliminary direction. Final mechanical fit, force range, electrical compatibility, control authority, performance and project responsibility require the actual machine details and written scope.
Is a web tension load cell the same as an FMS force sensor?
“Load cell” is common buyer language for a sensor that converts mechanical force into an electrical signal. FMS generally uses more specific names such as force sensor, force-measuring bearing, force-measuring block or measuring roller. The correct FMS family depends on whether the machine has a live-shaft, dead-shaft, pillow-block, cantilever, complete-roller or filamentary-pulley arrangement.
Can the EMGZ309 replace an older analogue tension amplifier?
FMS publishes the EMGZ309 as a plug-and-play replacement for analogue potentiometer-adjusted units and for use with FMS force sensors. That does not make every replacement automatic. Confirm the existing sensor and feedback signal, terminals, excitation, power supply, analog output, polarity, scaling, housing, cable, calibration procedure and the function of any connected PLC or controller before ordering.
Do we need to replace the force sensors when replacing the amplifier?
Not necessarily. Existing sensors may be retained when their exact identity, condition, feedback signal, wiring, mechanical loading, nominal force and calibration remain suitable for the new electronics and production duty. Unknown, damaged, overloaded, unstable, poorly sized or undocumented sensors may make complete station replacement the better path.
What is the benefit of EMGZ310.ComACT?
EMGZ310.ComACT is a compact digital strain-gauge amplifier with local three-key/LCD setup and optional FMS-ComACT app operation. FMS publishes app functions for viewing sensor feedback, logging and exporting short data records, and saving configuration settings. It is useful when straightforward setup and portable commissioning evidence matter. The correct standard or V05 input variant, housing and outputs must match the sensor and installation.
How is a web tension force sensor sized?
Size from the resultant force acting on the measuring roller—not the material-tension number alone. Provide minimum and maximum material tension, entry and exit angles, wrap, roller weight, force direction, number of sensors, speed, acceleration, mounting orientation, environment and expected overloads. Final sizing should leave usable signal at the low end without exposing the sensor to excessive load at the high end.
Can an FMS amplifier send web tension to our PLC?
Yes, when the correct model and interface are selected. FMS publishes amplifier paths with standard analog outputs and model-specific industrial interfaces including EtherNet/IP, PROFINET IO and EtherCAT. Define the PLC platform, protocol, scanner or master, channel count, update rate, cyclic data, units, scaling, parameter access, network policy and loss-of-communications behavior.
Does installing a load cell and amplifier automatically control web tension?
No. A force sensor and measuring amplifier provide a tension signal for display, alarm, trend or PLC use. Automatic regulation additionally requires a tension controller or a validated PLC control loop, a compatible brake or drive with enough authority, roll-diameter behavior where relevant, machine interlocks, safe modes, limits, tuning and acceptance criteria.
When should we use a CMGZ tension controller instead of an EMGZ amplifier?
Use an EMGZ measuring amplifier when the job is to condition and communicate the force-sensor signal. Review a CMGZ controller when the system must compare measured tension with a setpoint and command an unwind brake, unwind or rewind drive, or intermediate driven section. In a normal FMS closed-loop zone, the force sensors connect directly to the controller and a separate EMGZ amplifier is not normally required unless an independent monitoring path is specifically needed.
Can FMS equipment replace another manufacturer's load cells or amplifiers?
Some retrofit paths are purpose-designed, such as the UMGZP replacement direction for the discontinued Philips PR 9951 series. Other third-party replacements require a complete compatibility audit covering mechanics, force range, sensor signal, excitation, bridge, wiring, output, control function and documentation. Do not assume compatibility from appearance or nominal capacity alone.
What information should I send for a tension retrofit quotation?
Send the machine and process, material, width, speed, minimum and maximum tension, web-path drawing, entry and exit angles, roller type and weight, photos of both roller ends, shaft or journal dimensions, existing sensor and amplifier nameplates, wiring and outputs, PLC and protocol, desired monitoring or control functions, environment, equipment to retain, shutdown window and installation responsibilities.
Can Gauge Advisor troubleshoot or repair a failed machine onsite?
Gauge Advisor is the authorized FMS sales and applications support partner for selecting, scoping and quoting equipment and coordinating manufacturer review. Gauge Advisor is not presented as an emergency repair service, field maintenance technician or machine-safety authority. For an existing fault, Gauge Advisor can help collect the equipment identity and symptoms and route the request appropriately. FMS owns manufacturer product-service, repair, maintenance and factory technical determinations; field labor, electrical work, controls changes and safety responsibilities require separately qualified and contracted parties.
Is web guiding included in a tension retrofit?
Not automatically. Web tension regulates or monitors the pulling force in the material; web guiding corrects lateral position. A line may need both, but the guide additionally requires a material sensor, guide controller, actuator or steering frame, suitable geometry and a separate position-control scope. The embedded selector can evaluate both paths without treating them as the same function.