WAGO 857-409 Isolation Amplifier

Technical Overview

WAGO item 857-409 is an isolation amplifier/signal conditioner for bipolar and unipolar standard analog signals. It accepts configurable voltage and current input ranges and provides configurable voltage or current output ranges with electrical isolation between input, output and supply. The unit is configured via DIP switch and potentiometer, supports zero/span adjustment across the measurement range, and offers a selectable limit frequency of 100 Hz or 5 kHz. Designed for DIN-35 rail mounting in a 6 mm wide housing, it uses Push-in CAGE CLAMP® connections and operates from a 24 VDC SELV supply.

Key Features

Configurable via DIP switch and potentiometer
Accepts voltage inputs: ±5 V, 0…5 V, 1…5 V, ±10 V, 0…10 V, 2…10 V
Accepts current inputs: ±10 mA, 0…10 mA, 2…10 mA, ±20 mA, 0…20 mA, 4…20 mA
Provides voltage outputs: ±5 V, 0…5 V, 1…5 V, ±10 V, 0…10 V, 2…10 V
Provides current outputs: ±10 mA, 0…10 mA, 2…10 mA, ±20 mA, 0…20 mA, 4…20 mA
Zero/span adjustment of ±5 % of upper range value
Switchable limit frequency: 100 Hz or 5 kHz
Typical transmission error ≤ 0.1 % of upper-range value
24 VDC SELV supply with up to 40 mA current consumption
Push-in CAGE CLAMP® terminals for up to 2.5 mm² conductors
IP20 housing for DIN-35 rail mounting
Current input overload protection via resettable fuse

Technical Specification Matrix

Parameter	Value
Product type	Isolation amplifier
Configuration options	DIP switch; Potentiometer
Input signal type	Voltage; Current
Input signal (voltage)	±5 V; 0…5 V; 1…5 V; ±10 V; 0…10 V; 2…10 V
Input signal (current)	±10 mA; 0…10 mA; 2…10 mA; ±20 mA; 0…20 mA; 4…20 mA
Input resistance (current input)	≤ 50 Ω
Input resistance (voltage input)	1 MΩ
Input current (max.)	50 mA
Input voltage (max.)	32 V
Zero/span adjustment	±5 % of upper range value
Output signal type	Current; Voltage
Output signal (voltage)	±5 V; 0…5 V; 1…5 V; ±10 V; 0…10 V; 2…10 V
Output signal (current)	±10 mA; 0…10 mA; 2…10 mA; ±20 mA; 0…20 mA; 4…20 mA
Load impedance (voltage output)	≥ 2 kΩ
Load impedance (current output)	≤ 600 Ω
Residual ripple	≤ 10 mV (rms)
Limit frequency	100 Hz / 5 kHz (configurable via DIP switch)
Step response (typ.)	3.5 ms (100 Hz); 68 µs (5 kHz)
Transmission error (typ.)	≤ 0.1 % of upper-range value
Transmission error (max.)	≤ 0.2 % of upper-range value
Transmission error (under interference)	≤ 15 %
Temperature coefficient	≤ 0.01 %/K
Power supply type	24 VDC (SELV)
Nominal supply voltage Us	24 VDC
Supply voltage range	±30 %
Current consumption (default)	≤ 20 mA
Current consumption (max.)	≤ 40 mA
Rated voltage	300 V
Protection type	IP20
Test voltage (input/output/supply)	3 kVAC; 50 Hz; 1 min
Overvoltage category	II
Pollution degree	2
Insulation type (input/analog output/supply)	Functional insulation
Insulation type (adjacent devices)	Reinforced insulation (safe isolation)
Connection technology	Push-in CAGE CLAMP®
Solid conductor	0.08…2.5 mm² / 28…14 AWG
Fine-stranded conductor	0.34…2.5 mm² / 22…14 AWG
Strip length	9…10 mm / 0.35…0.39 inches
Cable type	Shielded cable
Width	6 mm / 0.236 inches
Height	94 mm / 3.701 inches
Depth from upper-edge of DIN-rail	97.8 mm / 3.85 inches
Mounting type	DIN-35 rail
Insulation material (main housing)	Polyamide (PA66)
Flammability class per UL94	V0
Fire load	0.488 MJ
Weight	39.2 g
Ambient temperature (operation)	-25…+70 °C
Ambient temperature (storage)	-40…+85 °C
Processing temperature	-25…+50 °C
Temperature range of connection cable	≥ (Tambient + 10 K)
Relative humidity	5…95 % (no condensation permissible)
Operating altitude (max.)	2000 m
Conformity marking	CE
EMC immunity to interference	EN 61000-6-2
EMC emission of interference	EN 61000-6-3
Standards/specifications	EN 61010-1; EN 61373; DNV
Country of origin	DE
Product group	6 (INTERFACE ELECTRONIC)

Industrial Applications

1. PLC analog isolation for mixed voltage and current field signals

Used between field transmitters and PLC analog I/O to isolate and condition bipolar or unipolar voltage/current signals in compact control cabinets. The module can translate among standard ranges such as 4…20 mA, 0…10 V, ±10 V, and ±20 mA while maintaining electrical isolation.

Problem Solved

Prevents ground-loop coupling and signal incompatibility when sensors and controllers use different analog standards or reference potentials.

24 VDC SELV3 kVAC isolation±10 V4…20 mA0…10 VDIN-35 rail6 mm width

2. Drive and process signal conversion in retrofit panels

Installed in retrofit machinery where legacy analog references must be matched to newer control hardware. DIP-switch selectable input/output ranges and zero/span trimming support calibration of existing process loops without redesigning the panel.

Problem Solved

Solves analog range mismatch between legacy instrumentation and modern control systems while preserving cabinet space.

DIP switch configurationzero/span adjustmentcurrent output ≤ 600 Ωvoltage output ≥ 2 kΩPush-in CAGE CLAMP®signal conditioner

3. Fast-response isolated analog conditioning for machine monitoring

Applied in monitoring circuits that require isolated analog transfer with configurable bandwidth. The selectable 100 Hz or 5 kHz limit frequency and fast 68 µs step response at 5 kHz suit machine signals that need faster propagation than typical process-only loops.

Problem Solved

Enables isolated transmission of faster-changing analog signals while allowing bandwidth limitation for noise reduction when needed.

5 kHz limit frequency100 Hz filter68 µs step responsetransmission error ≤ 0.1 %bipolar analog signalsIP20