Hitachi has picked up on the trend towards smaller and more powerful programmable logic controllers with its EH-150 PLC. This targets localised high-speed control applications, from fast- moving production lines to high-speed packaging and monitoring functions. It uses a 20MHz 32-bit Risc central processing unit with 4K or 8K memory, providing up to 8,000 steps and up to 256 digital I/O. The EH-150 PLC is part of the larger H-series family, based on the ActWin PC-compatible programming software, which will translate ladder diagram or other programming languages. The unit is modular, accepting up to 16 plug-in cards from a wide range of third-party suppliers. These slot into a base designed to take 3, 5 or 8 I/O modules. Power supply modules are available for AC or DC inputs, generating a control signal of 0 10V for industrial applications and 4 20mA for process applications. The CPU’s fast 50kHz counter makes the unit suitable for wrapping, bagging, plastics moulding and other high-speed work. The CPU on the more powerful 208 model has a built in modem interface for error messaging and unmanned monitoring and control capabilities. An integral real-time clock has battery backup in the event of mains failure. Two independent RS232 serial interface ports provide read/write speeds up to 38,400bps. They can work at the same or different speeds, for example with one connected to an MMI or Scada board and the other to a bar code reader, high-speed counter or extra serial board. The CPU can be replaced with a SoftPLC card, allowing the PC to do the control functions with the rack system being used for remote I/O. The EH-150, supplied by HID, costs around £803 for a 64 I/O PLC.
Modicon TSX Micro, Premium and Quantum PLCs are Year 2000 compliant, says supplier Schneider. The company has set up an audit service to answer enquiries about current and older PLCs in the Modicon, SyMax and Telemecanique ranges.
Modular Absopulse MX series inverters are available in five modules to provide N+1 failsafe redundancy in safety-critical drive systems. They are compatible with a master drive rated at 1000W and up to 19 slave drives. Cards, which are insertable without interrupting power to critical loads (with the exception of the 12V DC supply) include control and alarm functions.
Carlo Gavazzi has introduced an 11kW soft start unit for use with 3-phase squirrel-cage motors with nominal load currents of up to 25A. The company has also cut the prices of 1.5kW and 5.5kW versions. The soft-start units smooth the voltage when motors start and stop, reducing the stress on belt or chain drives, pumps and related pipework. They allow initial torque to be adjusted from 5% to 50% of nominal torque. Start-up times can be adjusted from 0.5 to 10 seconds and stopping times from 0.5 to 20 seconds. The units can be retrofitted on existing machines.
Simplatroll has introduced four compact, low-cost inverters for speed control of any small 3-phase motor rated up to 0.7A/120Hz. Two versions the Standard, with built-in potentiometer, and the External Speed Reference model handle 25/40W and 60/90W motors.
The B17, a brushless servo-drive from Micromech, is intended to be a low-cost replacement for almost any conventional brushed servomotor producing output torques from 0.1Nm to 20Nm, in four voltage ranges. Surface mount technology and Eurocard format keep costs down and linearity is said to be excellent.
BSL’s Combi service, based on supplying Siemens’ Combimaster integral drive packages, has been extended to include a gearbox service. This saves customers the task of sizing a gearbox and attaching it to a motor themselves. Variable Torque Combimaster units with a 3:1 speed range are intended for speed control of pumps and fans. The Constant Torque units, which have a 10:1range, have optional regenerative braking for fast stopping of conveyors and similar machinery.
Dietz-electronic, the German maker of AC drives, has been bought by Welsh industrial control company Focus Dynamics. Dietz’s range, which covers open and closed-loop control of motors with power outputs from 0.75kW to 65kW, is complemented by custom software skills and EMC expertise. The company’s Stuttgart base is one of the first of a planned worldwide network of Focus Centres which will sell drives, motors, pumps and fans.