Masoneilan 12430 Digital Level Transmitter with Switches and 2nd 4-20 mA

Overview

The Masoneilan 12430 is the fullest transmitter version in the Baker Hughes 12400 Series of digital displacer level instruments. It keeps the measuring head of the basic 12420 and adds hardware for plants that want extra outputs directly at the vessel: two independent isolated digital switch outputs, DO_1 and DO_2, and a second analog output, AO_2. Both analog outputs carry the level or interface signal, and HART communication is available on AO_1 only.

Seven Star LLC is a trusted supplier for Masoneilan and quotes the Masoneilan 12430 for projects in Oman and the GCC. Baker Hughes states that these extra outputs work only if they were ordered with the instrument, so the model code must be right at the time of the order. We check the action digit, the mounting digit, the protection code and the housing material with the customer before the RFQ is issued.

Wiring the Extra Outputs on the Masoneilan 12430

The switch outputs of the Masoneilan 12430 deserve attention at the design stage, because they are open-collector circuits. The manual describes two independent isolated outputs rated for a maximum of 1 A, and a load resistance must be placed in series to limit the current. It warns that 30 VDC across the switch terminals and 1 A cannot exist at the same time, and that doing so will destroy the digital output circuit. The switch terminals accept from 0.5 V to 30 V, and they are polarity sensitive, so the polarity must be respected during wiring.

The second analog output, AO_2, accepts a supply from 10 V to 30 V, whereas AO_1 accepts up to 40 V in the flameproof version and 30 V in the intrinsically safe version. The maximum load on each analog output is the supply voltage minus 10 V, divided by the maximum current. For intrinsically safe installations the manual lists entity parameters, and the secondary output is not supplied for intrinsic safety with the FM and CSA approvals, so the approval code in the model number must be reviewed against the wiring plan.

Operating Principle of the Masoneilan 12430

As with the rest of the series, the Masoneilan 12430 is a buoyancy device. The displacer changes apparent weight with the liquid level, the torque tube twists in proportion, and a non-contacting magnetic sensor turns the torque rod rotation into a signal. The microcontroller then scales the signal onto both 4-20 mA outputs, evaluates the two switch set points and drives the LCD. The scan time is under 60 ms and the power-up time is under one second.

Configuration of the switches is done through the instrument menus or through ValVue and a HART handheld. The manual lists the transmitter menus for the 12420 and 12430 together, so the same navigation applies to both models, and the access to the main functions can be locked with the hardware lock jumper in the instrument head. When the lock is in the secure position no new data can be written, and a LOCK message appears on the LCD if a pushbutton is pressed.

Key Features

The capabilities that distinguish the Masoneilan 12430 from the other models of the series are listed here:

• Second 4-20 mA output on AO_2, giving a duplicate level signal for a second system such as a local indicator or a safety logic solver.
• Two isolated open-collector switch outputs that the user can adjust for high and low level alarms.
• HART communication on AO_1 and local set-up through the LCD and three pushbuttons.
• NAMUR NE 43 fault levels of below 3.6 mA and above 21 mA on the analog outputs.
• Transmitter function covered by the 12400 Series SIL certification, with the SIL 2 device feature selectable.
• Operation of the extra outputs requires that they be ordered with the unit, so the model code must include them.

Industrial Applications

A level transmitter with its own switches, like the Masoneilan 12430, is useful on vessels that need a high-level or low-level alarm without extra instruments on the nozzle. Typical locations include separators, scrubbers and day tanks. The second analog signal lets one measurement feed two receivers, such as a DCS and a separate monitoring system, without a signal splitter.

The Masoneilan 12430 is often installed beside the control valve that it supervises. A loop might combine it with the Masoneilan SVI FF positioner on a Masoneilan 10000 Series double port valve. Seven Star LLC can include the level instrument in the same offer as the valve.

Related published Masoneilan pages: Masoneilan Type 87/88 spring-diaphragm actuators.

Technical Specifications

The table gives published data for the Masoneilan 12430 from the Baker Hughes instruction manual and safety guide, revision E.

Related Masoneilan level instruments include the Masoneilan 12400 Series digital level transmitter and Masoneilan 12800 Series pneumatic level controller.

Request a Quote for Masoneilan 12430

To request pricing or support for the Masoneilan 12430, send a formal RFQ to the Seven Star LLC instrumentation division with the vessel connection, range, specific gravity, process temperature and pressure, switch duties and the hazardous area approval required. We will confirm the model code and provide the Baker Hughes instruction manual from this page. In Oman and the GCC, Seven Star LLC supplies genuine products with manufacturer documentation.