Many control manufacturers
produce standardized units which are designed to apply to a large number of potential
applications. The units typically have a single function, for example, temperature
control, timing or speed readout. In some cases. the units may have a fixed,
built-in group of functions and the flexibility of being programmed is limited to
the extent that it is useful for commonly occurring categories of applications.
Units are generally sold to anyone who wants to buy them and come with instructions on how
to wire and configure the unit, and provides specifications which tell the buyer in
general terms what the unit will and will not do. Any
equipment or machinery manufacturer (OEM) may select between various models of these
control units (often from the controls manufacturer's published catalog) in order to
accomplish the required control task. In many cases, multiple units are needed
(which may come from different manufacturers) because the complete task requires more than
one single function (for instance, the combination of speed control, temperature
control and timing.)
In many cases, the logic and sequence requirements are complex enough to make a PLC
(Programmable Logic Controller) necessary to tie together all the control elements and
provide additional inputs, outputs and operator interface.
The OEM's engineering department makes the component selection, then works out how the
various components in the system will be wired together and configured (or
programmed). This information is then used to build a control panel, which consists
of the control units plus any necessary auxiliary equipment such as pushbuttons, terminal
strips, relays and contactors, sensors, etc.
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Howman Engineering works with
various OEMs to design and manufacture CUSTOM control units which are developed
jointly so it results in a product which is tailored to the OEMs particular application.
In almost all cases, the OEM is an established and experienced builder of equipment or
machinery which serves a particular and specialized industry. Also, typically, the
OEM has previously used some combination of off-the-shelf type units to control his
machines, appliances, etc. and understand the particular requirements in his specific area
of expertise. The application may be for existing machines, or for new ones in the
process of development.
The OEM generally wishes to combine the functions of some or all of the required controls
into a single integrated element which may include displays, keypads, or buttons, logic,
timing, sensor interfaces and input-output capabilities of various kinds. This
approach can provide an optimized, dedicated operator interface, simplicity of operation,
reduced cost and other desirable characteristics which may not be obtainable by assembling
a conglomeration of general purpose control units. The
OEM has the opportunity to specify a unique and proprietary "look" including
size, shape and color, and benefits from having significantly less wiring, configuration
and other work to do to make the complete piece of equipment. In many cases, Howman
can provide a nearly complete control system, consisting not only of the custom designed
components, but also panels, connection boxes, commercially available terminal strips,
relays, contactors, motor drives, solenoid valves, etc. (which would ordinarily be
supplied and wired by the OEM) reducing further the amount of work needed in the OEM's
plant to fully assemble the final equipment, appliance or machine |
