Modbus Side Tank Indicator Developed for Liquid Level Sensors

MTS Systems Corp USA has developed a new display meter to work with the Level Plus® MG transmitter with Modbus interface. The meter was developed as a Side Tank Indicator (STI) for storage tanks with the ability to interface via Modbus and display tank levels in feet, inches and 16ths of an inch. Plugandplay out of the box, users can choose to have the meter display product only, product and temperature, or product, interface and temperature.

“This new meter provides our customers with a STI that is capable of communicating via Modbus, can display level to the 16th of an inch, and has an explosion proof housing,� said Lee Aiken, product marketing manager, MTS. “Combined with the accuracy of our magnetostrictive sensing technology, the model MG transmitter and Modbus STI is an ideal package for level applications that require local monitoring of highvalue liquids, such as in petroleum tanks.�

The features of the Modbus STI include two relays (2A at 250 SPDT), a 4 to 20mA output, 120/240 VAC input power, 24 Vdc to the gauge, and an optional explosionproof housing. The display can show the measurement in feet, inches and to 1/16 an inch and temperature to one decimal point.

The Model MG transmitter monitors the product, interface and temperature all from a single process opening. Every transmitter is intrinsically safe, approved, and can be ordered with an explosionproof housing. The Modbus protocol also provides volume measurement with the usage of up to 100point strapping table and temperature correction according to API standards with a direct connection.

The Model MG digital transmitter satisfies the demand for a digital communication interface in the liquidlevel marketplace for vessels from 508mm to 18,288mm in height. Ideal for process control, bulk storage, precision inventory control and product level, interface level and temperature monitoring, the model MG transmitter features surfacemount technology and a proprietary highspeed signal processing integrated circuit. In addition, the microprocessor firmware features a flexible command interface, high noise rejection capability, builtin test functions, and automatic data error checking.

Outputs from the Model MG digital transmitter are communicated via a 4wire multidrop power and data bus, eliminating the requirements for individual cable runs from each tank. Serial asynchronous data formats (Modbus and MTS DDA) provide a direct interface to most types of computers and digital communication equipment.