Wiring: Connect the prepared 4-wire cable to the core processor terminal. Reinstall and tighten the cover, with a torque of 1.13-1.47 Nm for the aluminum shell and at least 2.15 Nm for the stainless steel shell. Connect the other end to the transmitter terminal according to the transmitter manual.
3.2 9-wire cable wiring (suitable for traditional transmitters or split core processors)
The connection of 9-wire cables should refer to the "Guidelines for Preparation and Installation of High Precision 9-wire Flow Meter Cables". Insert the bare ends of various colored wire cores into the corresponding terminals of the junction box and tighten them. Ensure that the gasket is intact and tightly close all housing covers.
3.3 MVD DirectConnect Safety Barrier Wiring
This is a key step in the application of intrinsic safety explosion-proof. The wiring is divided into two parts:
Intrinsic safety side (to core processor):
Connect the RS-485 A/B line to safety barrier terminals 43 and 44.
Connect the VDC power supply (+/-) to safety barrier terminals 42 and 41.
The shielding wire of the core processor is suspended on the intrinsic safety side and not connected.
Non intrinsic safety side (to remote host and power supply):
Connect the RS-485 cable to terminals 13 and 14.
Connect the VDC power supply to terminals 11 and 12.
Grounding principle
Good grounding is the foundation of measurement accuracy and system safety. The instrument must be grounded according to the applicable standards on site, such as IEC 60079-14 or ISA 12.06.01.
Natural grounding: If the process pipeline is well grounded, the sensor will be automatically grounded through flange connection.
Mandatory grounding: If the pipeline is not grounded, a copper wire with a diameter of 2.08mm ² or larger must be used to directly connect the grounding screw on the sensor electronic component housing to the ground, and the grounding impedance should be less than 1 ohm.
Security protection and maintenance
5.1 Sensor shell blowing
In some applications, it may be necessary to blow the secondary housing of the sensor to remove moisture or combustible gases. Before operation, the process must be stopped or switched to manual control to prevent measurement interference.
Remove the blowing joint plug and wrap it with Teflon tape for future use.
Connect an inert gas source (nitrogen or argon), and adjust the inlet position according to the gas density (for heavy gases such as argon, the inlet should be at the bottom; for light gases such as nitrogen, the inlet should be at the top).
Inject gas to replace air, and the blowing pressure must be kept below 0.5 bar to prevent the pressure on the casing from affecting sensor calibration.
After the blowing is completed, immediately seal the inlet and outlet with plugs to ensure a tight seal to prevent air from being sucked back.
5.2 Explosion disc pressure relief protection
The HPC sensor housing is equipped with a rupture disc as a secondary pressure protection device. In extreme cases where the flow tube ruptures, the rupture disc will release high-pressure medium in a directed manner.
Installation direction: The installation direction of the sensor must ensure that the pressure relief path avoids operators and critical equipment.
Maintenance warning: Do not linger in the pressure relief area. Once the rupture disk ruptures, its seal becomes ineffective and the instrument must be stopped from use and replaced. If the blasting disc is removed, the shell will lose its secondary protection function and must be purged again.
