Programming
Chapter 3
35
To obtain the time required from activation of the input that makes the rung
containing the AF1 PROM function true until the correct answer for the
function is in the data table, you must add the following times to the values in
Table 3.B:
Input delay time (from specification for specific input)
One program scan time and one I/O scan time multiplied by the number of
scans specified in Table 3.B.
Methods for determining these times are presented in Mini-PLC-2/15, series B,
Programmable Controller Programming and Operations Manual (publication
1772-804).
In this section we explain the following for each of the AF1 functions:
What it is
How to enter it in your program
Its format in the data table
a.word arrangement
b.digit location
Sample entry and display rungs. Although there are several techniques to
enter this data, we use get instructions.
Error messages. If an AF1 function has special error message responses to
specific illegal programming procedures, we state these responses.
Status Bits
The most significant four bits of the most significant word of the result data
area are reserved for status bits. These bits have the following meanings:
Enable = bit 17
Sign = bit 16
Done = bit 15
Error bit = bit 14
The enable bit is set at the start of an AF1 function and reset upon completion.
The sign bit, if set, indicates a negative value.
Programming Specific
Mathematical Functions
