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Plant- and Machine-Wide Communications
News Release from: Moog Controls | Subject: Analogue DIN modules
Edited by the Engineeringtalk Editorial
Team on 07 September 2004
Custom DIN modules for flexible control
The DIN module electronics range of products provides standard building blocks for creating customised control systems for open and closed-loop control.
The DIN module electronics range of products provides standard building blocks for creating customised control systems for open and closed-loop control This approach offers a set of products that are built in quantity with full customer support documentation for installing, commissioning, and maintaining the resulting solution
For this reason it is preferable to aim for standard catalogue modules.
However there are instances where small changes can offer major benefits in terms of cost and performance.
Generally, those changes will be within the available functionality of the module and be reflected in the dash number at the end of the model code.
Moog's standard PI servo amplifier has given birth to a range of customised models with variations such as: additional environmental protection for H2S exposure in geothermal power stations (achieved with a conformal coating and reloading of some devices where material corrosion is a potential problem); and inclusion of 4-20mA output for turbine applications.
Typical changes to the "parent" product involve environmental protection, change of resistors, additional loading to the available capacity of the existing PCB layout.
Generally this involves taking a standard product from stock and making minor changes.
Moog can provide many such changes within a very short delivery period at similar prices to the parent product.
A 10% premium is typical for small changes.
If quantities are sufficient, it may be possible to justify a new product development.
The Mobile servo amplifier has been designed for a wider range of customisation with specific building blocks allocated.
Its designation as "Mobile" relates to the ruggedised power supply that will operate from the very noisy automotive environment and obviously, it is also suited to 24V unregulated industrial supplies.
This closed-loop servo amplifier has provisions for easy loading of options such as: a frequency to voltage convertor for velocity feedback; nonlinear function; and a dual gain amplifier for high-speed, high-accuracy positioning.
A recent application used a DIN module to control the vertical movement of a lock crane boom.
Located on the River Murray in South Australia is a series of locks for flood control.
Concrete beams are lowered into slots to vary the height of underwater barriers.
The task of the control system is to simplify the control of the excavator boom to achieve an accurate horizontal movement of the beams as they are moved into position.
A closed-loop position control system with feedback from a pendulum sensor has been applied with the following components: a servo valve with "outdoor" environment protection; a customised Mobile servo amplifier; and a pendulum level sensor.
The Mobile servo amplifier was chosen due to its suitability to operate directly from standard "automotive" style power supplies without the risk of electrical damage and the ease of adding custom control requirements.
DIN style packaging meant that a compact and reliable installation could be achieved in this relatively harsh environment.
Of course, there is a limit to how far we can go with analogue electronics.
For complex control with digital interfacing it is preferable to use digital solutions such as the Moog MSC servo controller or DIV digital interface valve that offer complete flexibility with respect to control strategies.
However, many simple control systems will be successfully implemented with the standard Moog DIN modules or from simple customisation of these analogue electronic assemblies. Request a free brochure from Moog Controls ...
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