Measurement amplifiers
Convert the millivolt signal of a strain-gauge bridge into a noise-resistant, analogue current signal. Special variants output digital bus signals.
From millivolts to a current signal
A strain-gauge bridge sensor delivers a differential signal only a few millivolts large, which is vulnerable to electromagnetic interference over long cable runs. The measurement amplifier excites the bridge, amplifies the differential signal and converts it into an impressed 4…20 mA current loop, which can be carried hundreds of metres to the PLC or display without level loss.
The cabinet unit MV-0420b sits next to the controller. The in-line amplifier MV-0430-LW is integrated directly into the cable at the sensor, ideal for retrofits. The R-0316 model combines a measurement amplifier and overload-protection unit in a single enclosure.
Models
Measurement amplifier Type MV-0420b
- Input
- 1× strain gauge
- Supply
- 24 V DC (20…30 V DC)
- Signal
- Current loop (4…20 mA)
- Connection
- EMC cable gland, screw terminals
- IP rating
- IP 65 (EN 60529)
- Material
- Die-cast aluminium
- Dimensions
- 125×80×54 mm
- Operating temperature
- −25…+70 °C, optional −40…+80 °C
Suited for retrofitting strain-gauge sensors to a current-loop signal for the PLC. Setup without special tools.
Datasheet: on request
In-line measurement amplifier Type MV-0430-LW
- Input
- 1× strain-gauge bridge
- Supply
- 24 V DC (8…36 V DC)
- Signal
- Current loop (4…20 mA)
- Connection
- M12 connector
- IP rating
- IP 65 (EN 60529), optional IP 68
- Material
- Stainless steel
- Operating temperature
- −40…+80 °C
Converter for strain-gauge bridge sensors to a current loop, integrated directly into the cable.
Datasheet: on request
Overload protection with current output Type R-0316
- Input
- 1× strain-gauge bridge, 1× current loop (4…20 mA)
- Supply
- 230 V AC (50/60 Hz); optional 24 V DC or 110 V AC
- Output
- Current loop (4…20 mA)
- Switching contacts
- 2× relays (changeover) for overload and slack rope
- Dimensions
- 220×120×80 mm
Dual function as a measurement amplifier and overload-protection unit. Suited for retrofitting strain-gauge sensors to a current-loop signal with direct cut-off logic. See Overload protection for details.
Datasheet: on request
Application examples
- Retrofitting a PLC interface to existing strain-gauge transducers
- Long sensor cables in high-EMC environments (cranes, outdoor plants)
- Cabinet builds with distributed sensor pickup
- Special variants with digital bus output (Profibus, CAN bus, IO-Link)
Other measurement electronics
- Overload protection
- Analogue compact overload-protection units R-0311 to R-0316 in fail-safe technology.
- Load spectrum counter
- Digital controllers MVD-0485 and SKS-0586 with FEM 9.755 evaluation.
Enquiry
Availability of the digital variants and the right sizing for your case is something we work out up front. Get in touch.