I-O Display Systems Basic I/O Product - Manual (Page 52)

Introduction 1
1-6(Vol.2)
Squarewave Can generate squarewaves with programmable On and Off
periods. On and Off periods have a base range from 0.01 to
2.56 seconds. Resolution can be further multiplied by a factor
of 1-256 on a system wide basis. Re-triggering is available.
Pulse Generator Can generate 1-65,535, 50% duty cycle pulses whose equal on
and off periods can range from 0.01 to 2.55 Sec. Resolution can
be further multiplied by a factor of 1-256 On a system wide
basis.
Extended capabilities:
In addition to operating under the control of a host, Option/L of the BASIC I/O AD has the
ability to perform local control functions without the host. Local control functions (LCFs) can
insure the continued safe operation of closed loop control should the host of its
communication link fail. In addition, LCFs can substantially reduce Host computational load
or communications traffic.
Once characterized, Local Control Function blocks enable the BASIC I/O AD to perform
control tasks without the constant involvement of the host computer. After configuration and
activation via the host instructions, LCFs take data from their input ports, perform
computations and send the results to their outputs where they may drive output modules, or
other BASIC I/O AD internal functions.
Utilizing the LCF’s to perform simple logic tasks such as analog comparisons, summations,
differences, sequence generating or state machine operations eliminates the need for
programmable controllers or special purpose circuitry. This capability allows a more effective
use of the host computer and its communication link because the LCFs handle the operation
of the designated control function. In the meantime the host is only required to monitor
over-all system status and generate the system displays and reports. This is particularly
valuable for systems using modems for communications.