H2-meTCD 4-20mA
Features:
• Accurate detection of hydrogen levels in air and nitrogen up to 15 vol-%
• Fast response and recovery times
• Applicable in relative humidity (rh) between 0 % to 100 %
• Temperature range -20 °C to +85 °C
• Linear output up to 5 % vol-%
• Very low power consumption < 10 mW
• 4-20 mA current-loop transmitter with reverse voltage operation and over-voltage surge protection
• Supply voltage with reversed bias protection
H2-meTCD 4-20mA is a hydrogen sensor for applications without oxygen and is based on a thermal conductivity operation principle. The sensor contains a Si-based heated transducer, fabricated by anisotropic etching, and onboard electronics, including the voltage sources for the transducer, a non-volatile digital rheostat for adjusting the Wheatstone bridge with the transducer, an instrumentation amplifier, and a secure 4-20 mA current interface. It is designed for use in a variety of applications which require an accurate hydrogen determination in nitrogen or other non-oxygen-containing atmospheres.
1 +7.5 V positive supply voltage with respect to ground
2 Current output connect to 0 V of the current loop
3 Ground of the internal electronics. The pin is electrically not connected to the housing
4 Current input connect to +24 V of the current loop*
SCL Clock line of the I2C bus**
SDA Data line of the I2C bus**
* The current loop must be galvanically decoupled from the supply voltage. No common mass is allowed. The current loop must contain a driving voltage source (recommended value: +24 V).
**If connected, provide necessary pull-up resistors to SCL and SDA (e.g. 4.7 kOhm).