Safety Barriers

I. Overview

● The LU-A22 safety barrier supplies power to field transmitters, limits hazardous energy from entering the hazardous location through the intrinsically safe terminals, and converts DC signals into isolated standard process signals.

● Can be connected to two independent two-wire transmitters.

● Two independent input and output channels; for each channel, the input, output and power supply are magnetically isolated from one another.

II. Technical specifications

●Input parameters (hazardous area signals)

For current input  Input range: 4~20mA, 0-20mA, 0-10mA

Distribution voltage: ≥16VDC

Output resistance: built-in input resistor 100Ω

For voltage input  Input range: 1~5V, 0~5V, 0~10V

Input impedance: ≥500KΩ

Thermocouple input (millivolt signal), input range:

Minimum millivolt span: 3mV

RTD input, input range:

Permissible lead resistance : ≤5Ω (identical for the three wires)

●Output parameters (safe area signals)

For current output  Output range: 4~20mA, 0-20mA, 0-10mA

Permissible load: ≤350Ω

For voltage output  Output range: 1~5V, 0~5V, 0~10V

Output impedance: ≤500Ω

●Intrinsic safety parameters

Linear current/voltage                      Thermocouple/RTD

Explosion-proof marking: [Exia] ⅡC           Explosion-proof marking: [Exia] ⅡC

  Maximum permissible voltage Um: 250V         Maximum permissible voltage Um: 250V

  Maximum output voltage Uo: 28V           Maximum output voltage Uo: 12V

Maximum output current Io: 93mA          Maximum output current Io: 24mA

● Ambient parameters

Power sup ply: 20-30VDC

Ripple factor below 10%P-P, approx. 1W 

Power indicator lamp: green LED, lit when the power is supplied

Operating temperature range: -20~ +60°C

Operating humidity range: 0 ~ 95%RH (non-condensing)

● General technical parameters

Standard accuracy: ±0.1%

Temperature drift: ±0.015%/°C

Response time: ≤10mS

Insulation resistance: 2.5KV, 1min, 50HZ between input, output and power supply

Isolation strength: input-output-power supply ≥100MΩ/500VDC

Effect of load resistance variation: ±0.1%/250Ω (for current output)

                   ±0.1% (for voltage output)

Power-on stabilization time: ≤3s