PLC functions and capabilities are being usurped by a new class of emerging products that are best called general machine controllers, or GMCs. These devices are a mix of motion control, PC architectures, Windows operating systems, PLC programming in IEC 61131 languages, and network communications. Many GMCs are being offered by traditional PLC vendors, which call them a variety of names, including automation controllers, automation platforms, or industrial controllers.
It appears that PLCs have carved out a huge, unassailable niche of their own at the low end of the machine control market, while GMCs are moving in from the top, replacing high-priced traditional automation products.
The following is the final installment on PLCs. Click on "New Products" under Recent Articles on the home page to review the first two installments.
Servo Amplifier Boards
The AMP-20420 two-axis and AMP-20440 four-axis servo amplifier boards attach directly to the 96-pin DIN connector of the company's DMC-2143 controller without the need for any cable or wiring, and can drive brush-type servomotors up to 200 W. The 20440 contains four transconductance PWM amplifiers on a single 4.95x3.75 in. board, while the AMP-20420 has two PWM amplifiers. Each amplifier produces up to 200 W and accepts 20-60 VDC, 3.3 A with no external heat sink required.
Galil Motion Control
Digital Gets Tough
Four digital modules for Compact FieldPoint and LabView Real Time control applications include the cFP-CTR-500 and cFP-CTR-502 digital high-speed counter modules and the cFP-PMW-520 and the cFP-PG-522 digital output modules. These small, eight-channel digital modules can withstand shock, vibration and wide temperature ranges. Applications include embedded machine control, industrial data acquisition, data logging and in-vehicle applications.
Panel-Mount PLC Packs PID
The FP-e PLC has an LED display, six programmable function keys, PID control with auto tuning, motion control commands, two RS-232 ports, and memory for 2.7 K steps, all in a 1/16-DIN enclosure. Programming is via IEC 61131 languages. The PLC has 180 instructions, 32-bit integer and floating-point math, high-speed counter, eight inputs and six outputs. The optional temperature model has two thermocouple inputs. It can control two axes of stepper or servo motors simultaneously.
The 1756-L61 and L62 ControlLogix controllers provide memory, speed, and processor capabilities for high-speed motion and drive-system applications. OEMs can run more motion axes at lower coarse update rates, as well as run more demanding logic in the same processor with motion. The 1756-L6x controller has an advanced CPU with a high clock speed and a built-in floating-point math coprocessor. This combination executes discrete logic up to twice as fast as the 1756-L55 controller. Function blocks execute four to five times faster.
Handles the Harsh
The AX10402 is a PC/104 standard expansion CPU module with a low-voltage 386SX 40 MHz embedded core engine. It also supports M-System's DiskOnChip and provides anti-vibration storage suitable for harsh industrial automations. On-board Multi I/O includes one SPP/EPP/ECP parallel port, one floppy port, and two 16550 UARTs-compatible serial ports as RS-232. Watchdog timer features 16 levels, 0.5-1,000 sec. Axiomtek
The OpenNet Controller offers CPU modules that come standard with two RS-232 ports, one RS-485 port, built-in high-speed counter, 224 I/O (expandable to 480), 512 Interbus Remote I/O, real-time calendar/clock, and 16K words program capacity with optional flash miniature card slot. The MicroSmart and ONC can also be linked to as many as 32 other MicroSmart modules as a master or slave, or 1:N computer link.
The Tempcon PID temperature controller is well suited for packaging machine temperature control when thermal cutoff or forming applications are employed. The module is designed as either a standalone unit or integrated into a device-level network (CanOpen, DeviceNet, Interbus, and Profibus) or Ethernet. The module can be configured as a PID two-position controller, a three-position controller, or a motor step controller for closed-loop applications.