Digital Bus Output Signal Transmission

Asked by aodai 6 years, 11 months ago | 2 Answers

If I use digital bus signal transmission, what is the recommended type of transmitter?

2 Answers

Normandy 6 years, 11 months ago

If pneumatic output signal transmission is used, the transmitter should have:

  • Linearized 3-15 psi output
  • NPT signal connections

The transmitter should be provided with zero and span adjudtment which should be accessible without the removal of a dedicated cover.

The zero output should be adjustable as a minimum to +/- 15% of the upper range limit.

Normandy 6 years, 11 months ago

Fieldbus Foundation or Profibis is the preferred transmitter.

Also, if 4-20mA output signal is used, it should be protected from reversal of normal supply voltage.

The transmitter should also

  • Have an isolated linearized output of 4-20mA
  • Operate over a 24V DC (+/- 30%) two wire loop
  • Have a voltage drop of less than 13 volts at maximum current
  • Have an accuracy of +/- 0.5% of operating span, including pressure, temperature, hysteresis and power supply effects