Division of Catalytic Industrial Group, Inc.
20th and Sycamore • P.O. Box 827
Independence, KS 67301
800.835.0557 • 620.331.0750 • Fax: 620.331.3402
E-Mail: ken@cat-group.com

HotCat spacesaver skid-mounted automatic models HC100 and HC125.

Level 1 Automation is Based on an Allen-
Bradley FlexLogix PLC and Allen-Bradley 400
Panel View Plus Modular Graphic Terminal. 

This distributed approach to control reduces field wiring and maximizes performance, because the controller and I/O are close to the heater. FlexLogix achieves distributed control without compromises such as reduced processing power and programming capability.  These compromises are common with traditional distributed control solutions.

FlexLogix also uses compact, DIN-mounted Flex I/O system modules, which have been field-proven in thousands of industrial applications. This control configuration is fully automated, with all process controls resident in the PLC.

The Panel View Plus terminal is a sophisticated HMI (human-machine interface) that provides greatest operator flexibility and data output.

Level 2 Automation is Bruest’s
Semi-automatic Control Option 

It uses a Control Microsystems PLC, with an unlimited number of PID controllers for feedback control, and an operator interface that is more compact that the one used in the fully automated system. The semi-automatic option uses a manual thermostatic gas valve as the primary temperature control, and adds and takes away heaters when the manual controls require assistance to maintain the discharge temperature within the operator-specified window.

The gas train has pressure relief valves following the pressure regulators in the fuel gas train.  Bruest has eliminated the inlet gas temperature gauge and RTD (resistance temperature detector) but has retained these instruments on the discharge, including the independent high-limit RTD sensor. Fuel is electronically controlled to eight independent zones; supervision of the heater safeties and system preheat cycles is also automated.  Fuel is modulated to provide precise temperature control.  There is no significant difference in accuracy between the fully automatic and semi-automatic units in this regard.

The interface used in Bruest semi-automatic units is basic, and the display somewhat less intuitive than the one used for the fully automated system. The semi-automated control configuration uses a 4-line/ 160-character display from Control Microsystems; a larger display is available.

Level 1 and Level 2:  Key Differences

The control packages for both Level 1 and Level 2 automation have similar capabilities in terms of basic operation for manual and automatic, or semi-automatic modes of operation. The Level 1 automation option is slightly more user-friendly, with more advanced features. The units have similar capabilities to connect to larger networks, and both offer wired Ethernet.  

Allen-Bradley offers a variety of A-B and third party solutions. The Control Microsystems solution offers optional features, including wireless Ethernet, spread spectrum radios in two frequency ranges, industry-standard Modbus®  protocol to simplify integration with SCADA software, various modem choices, and uninterrupted power supply (UPS systems) as building blocks for interconnectivity.

The Control Microsystems hardware has an advantage in that it is engineered for continuous operation in conditions of -40ºF to 158°F.  The A-B products have an operating range of 32ºF to 130ºF, and thus require panel heaters during the winter.  They may also present an issue on the upper end of the range in enclosed panels during the summer.  Low power units are available if any portion of the configuration requires enhanced back-up.

Bruest has chosen components for both automation options
that are widely used in SCADA systems worldwide,
particularly utility applications where robust performance
and accurate data acquisition is essential.

HotCat Application Questionaire

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Bruest HotCat gas heaters are protected by
US and Canadian patents.