It is against the background of the demands for more I/O and more functionality combined with the need for freedom from restrictions from software and physical size that the CPM family was designed.
In recent years, the benefits of micro controllers in applications requiring low I/O, with basic functionality, has led to demands for similar controllers suitable for more complex applications requiring higher I/O and increased functionality. This is with the proviso that there was no compromise on the perceived benefits of micro controllers, in particular their ease of use and cost-effectiveness.
Size, too, is a factor.
In many applications, the size of the PLC is a major factor in its selection.
Thus the Omron CPM family of micro PLCs was conceived. It is against the background of the demands for more I/O and more functionality combined with the need for freedom from restrictions from software and physical size that the CPM family was designed.
The range allows the designer greater flexibility than ever before, giving a seamless utilisation across a wide variety of applications.
From the compact CPM1A to the unique modular CPM2C and including the networking SRM1 that distributes its I/O via a built-in two-wire bus, the CPM micro PLC family shares the same core architecture.
This means that programs are transportable across all units, the same connectivity is available to MMI (man-machine interfaces) and PCs (personal computers) and a standard instruction set is provided, all of this being enhanced by the advanced micro controller options.
The family starts with the very compact, cost-effective CPM1A micro controller that is ideal for numerous sequencing applications, either as a miniature machine controller or as a sensor controller.
The unit has full MMI and PC connectivity and programs are fully upwardly compatible with the other micros in the CPM family.
The CPM2A complements the CPM1A's practicality, providing sophisticated functionality for more demanding applications.
This high-function unit includes features such as multiple counters, 10 kHz pulse output and analogue control as well as temperature sensor inputs.
Top of the range is the modular CPM2C micro PLC.
This unit shares the enhanced functionality of the CPM2A, yet gives the OEM designer one major additional benefit - its size! It is an ultra-slim, compact and modular design, which makes it the ideal choice for applications where space is at a premium, yet a high level of functionality is still required.
In addition, there is the CPM2B, a micro controller that is designed to be tailored to meet the specific needs of an OEM.
This product demonstrates the total flexibility of the system, whilst maintaining full compatibility and connectivity with the rest of the 'standard' CPM family.
Also aimed at the machine builder, the SRM1 is the world's smallest 256 I/O PLC, with the benefits of a fieldbus system built-in.
Although little bigger than a matchbox, the SRM1 has a highly functional machine control instruction set, combined with the capacity to handle up to 256 distributed I/O points via its fieldbus master, with an update time of less than 1ms.
This is distributed on Omron's newly developed high speed serial bus, CompoBus/S, which offers ease of set-up, with all the configuration handled within the system to give a 'plug-and-play' installation.
This makes the SRM1 ideal for applications such as conveyors, where there is an inherent need for distributed control.
Both the CPM2A and CPM2C offer designers compact packages with functions such as programmable terminal connections through a built-in RS-232C port, positioning functions, and high-speed counters.
In many instances, such as for smaller food packaging equipment, special-purpose machines, conveyors, cranes and many other common industry applications, either unit provides all of the functionality required, as standard.
Both support one-axis high speed counters (20 kHZ single-phase or 5 kHz two-phase and four-axis high speed counters (2 kHz single-phase).
This encompasses applications such as the measurement of cardboard length or string.
Both also have position control functions including one-axis pulse output with trapezoidal acceleration and deceleration as well as two-axis simple pulse output.
A typical example would be the simultaneous control of a servomotor feed and the speed of a conveyor.
The analogue control could be for temperature control, synchronised pulse control gives a scaling factor down the line (again a typical requirement in a packaging application) and high-speed processing is a vital feature if line speed isn't to be limited by processing time.
Another typical application is the conversion of a conveyor system to modular control by using the CPM2A connected to the optional CompoBus/S I/O Link Unit (8 inputs and 8 outputs), allowing line additions, faster operation and reducing system start-up time.
There are a twelve models of CPU unit with various combinations of power supplies (AC or DC), outputs (relay or transistor) and I/O points (30, 40 or 60).
This gives a package to suit almost any application.
In addition, I/O can be expanded with the addition of easy-to-connect I/O units. The CPM2C offers 10 models, with DC power supply and various combinations of relay/transistor outputs, terminal block/connector I/O connections and optional clock function.
The type of outputs and number of I/O points can be tailored to suit the needs of specific applications - and using expansion I/O units, this can be expanded to a massive total of 140 I/O points! The RS232 ports on the CPM2A and CPM2C give direct connectivity with Omron's Programmable Terminal, for ease of control and function adjustment, or with a PC for simple programming via the SYSWIN support software.
Two units can be connected in a one-to-one RS232 link and the host computer can be networked to several units using RS-422 adapters.
Even standard serial devices, such as bar-code readers, can be connected with no-protocol communications.
The CPM family of microcontrollers never force the machine builder to compromise on the design of his control system because they are seamlessly scalable to match individual system requirements, and programmes are 100 per cent transportable between the various sized units of the range.
They are easily connectable to other control elements such as PCS and MMIs and there are option for temperature, motion and other functions Key characteristics of the CPM range will make the control engineer's life significantly more straightforward, including its highly distributed I/O, the fact that no configuration is required, the built-in I/O master, and not least the fact that it is so small that it will fit into virtually any panel.
