ISA S61.1 : 1976

1 Scope
2 Executive interface
2.1 Control of program execution
2.2 Starting a program immediately or after a
     specified time delay
2.3 Starting a program at a specified time
2.4 Delaying continuation of a program
2.5 Program termination accomplished using present
     standard
3 Process input/output function interfaces
3.1 Control of analog and digital sensors and outputs
3.2 Analog inputs in a sequential order
3.3 Analog inputs in any sequence
3.4 Analog output
3.5 Digital input
3.6 Momentary digital output
3.7 Latching digital output
4 Bit string manipulation
4.1 Types of manipulation
4.2 Logical operations
4.3 Shift operations
4.4 Bit testing and setting
5 Date and time information
5.1 Obtain time of day
5.2 Obtain date
Appendices A and B

Describes external procedure references for use in industrial computer systems. Allows interface of programs with executive routines, process input and output functions allow manipulation of bit strings and provide access to time and date information. Intended for use with programs written in FORTRAN.