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Laboratory Electronics

The multi-port cards RS232C series LB-240 and LB-280 UPS

  • 4 or 8 ports RS232C 
  • UPS control
The multi-port cards RS232C series LB-240 and LB-280 UPS

Card designation

The multi-port cards series LB-240 and LB-280 are designed to work in standard IBM/PC computers, what allows on connecting each one with 4 (LB-240) or 8 (LB-280) peripheral devices using asynchronous interfaces RS232C. It is possible to increase the number of devices by using the next interface cards LB-240/280 configured with adequate successive addresses.

The cards collaborate correctly with the following operating systems; DOS, WINDOWS 95/98, LINUX, UNIX, QNX etc, they use the drivers that already exist in those systems; for the HOSTESS card standard.

Drivers for various systems can be found f ex.; on the following internet page: http://www.comtrol.com/, where one should use the option: Hostess 550/554 - (Non-Intelligent, Buffered). In the majority of cases during the installation process the card type is automatically detected by the system. An example of how to install the card LB-280 for Linux RedHat6.0 distribution with kernel 2.2.5 was introduced in the description attached.

The cards are made in a version with no buffering (with series transmission systems type 16450) or with 16 bit FIFO on each channel RS232C (with systems type 16550).
The buffering cards have adequate markings: LB-240B and LB-280B.

System collaboration with a UPS feeder

The cards series LB-240 and LB-280 are equipped with additional junction DB9 assigned to be connected with a UPS. It allows on direct computer and UPS collaboration, which means receiving its signals: Power Fault and Low Battery.

The signals are available in many standard UPS devices and allow the system's software on adequate reaction when detecting the alarm states like: lack of network power supply and starvation of the UPS batteries.

Beside when collaborating with some of the UPS devices the system can fully control the feeder's work � the electronic card system allows on the UPS to be programmed to switch off every time when the system is (closed down) coiled, and automatically switched on or upon user's direct order. The solution proposed by us eliminates two problems that exist in the UNIX systems:

  • UPS battery discharge in case of long taking power failures,
  • possibility of incidental switching off the server's power supply by the personnel.

Card configuration

The configuration is done by choosing the base address (available addresses A5...A12 for the card series LB-240 and A6...A12 for the card series LB-280) and the interruption number entered by the card (available are IRQ2...IRQ7 and additionally in the card LB-280: IRQ10, IRQ11, IRQ12 and IRQ15). Optionally one can use (in some of the systems it is necessary) the card's  interrupt mask registry for each one of the channels.
The card configuration under Linux is included in the description attached.

Card construction

The cards are equipped with a standard voltage interface RS232C, but only the data lines TXD and RXD were used. In the card LB-240 additionally the device synchronization line RTS and CTS was used.

All of the cards outputs are equipped additionally with two types of the current loops:

  1. +/-10 mA, designed for collaboration with terminals and galvanic separators LB-300 LAB-EL,
  2. 0/20mA, designed for collaboration with other peripheral devices.