ZTD is suitable for level, interface or density measurement with standard output signal 4~20mA DC.

Principle of operation

ZTD series intelligence displacer level (interface) transmitter consists of imported original DLC3000 series intelligence level controllers and displacer measuring compartment, measurement organ, cageless displacer and torque tube, etc. The measured medium level changement brings the location of cageless change, which is transferred to torque tube components. Torque tube and core axle synchronous rotate.

The magnetic field of haul-effect sensor detecting is changed by magnet rotating which is fixed on the torque tube core axle. This sensor converts the magnetic signal to electric signal. DLC3000 series intelligence level controller adopts controller and relative electron circuit to measure the process variable, supply current output, drive LCD meter and supply HART communications ability. Microcontroller receives the electric signal which has been compensated and linearized by ambient temperature. And at the same time, compensates the liquid density change aroused by process variable change. D/A output circuit accepts microcontroller output and supply 4~20mA electric output signal. LCD can indicate analog output, display process variable, process temperature (if installed RTD), degrees of torque tube rotation and percent range of variable, etc.

Supply Requirements: 12 to 30 volts dc; instrument has reverse polarity protection.

Reference accuracy: 0.5%; 1%.

Input Signals: Level, Interface or Density: Rotary motion of torque tube shaft

proportional to changes in liquid level, interface level, or density that

move the displacer up or down.

Temperature: Temperature detector can compensate the change of

density by temperature change.

Output signal: Analog: 4 to 20 milliamperes dc (direct action increasing level,

interface, or density increases output; or reverse action increasing

level, interface, or density decreases output)

Digital: HART 1200 BaudFSK (frequency shift keyed)

Operating influences: Power supply effect: Output changes <±0.2% of full scale

when supply varies between min. and max. voltage specifications.

Temperature: The combined temperature effect on zero and

measuring range without displacer measuring compartment is less

than 0.03% of full scale per degree Kelvin over the operating

range 40ºC to 80ºC.

Alarm jumper: Self-diagnostics that detect an error (e.g.,

electronics failure) that would render the process variable

measurement inaccurate. The instrument can also be configured to

indicate a process variable high or low alarm. It depends on the

user-selectable position of the alarm jumper. 

LCD meter indications: LCD meter indicates analog output, and also can be configure

to display process variable, process temperature, percent

range, and degrees of torque tube rotation.

Protection category: IP66

Min. density or differential density: ≥0.08g/cm³

Electrical Connections: Two 1/2-14 NPT female conduit connections; one on bottom

and one on back of terminal box. (M20×1.5 adapters available,

please notify when ordered.)

Process temperature: see below

Material and application temperature: see below

Ambient temperature and Humidity: see below