83
Placing other instructions between CMP(20) and accessing EQ, LE, and GR
may change the status of these flags. Be sure to access them before the de-
sired status is changed.
EQ: ON if Cp1 equals Cp2.
LE: ON if Cp1 is less than Cp2.
GR: ON if Cp1 is greater than Cp2.
The following example shows how to save the comparison result immedi-
ately. If the content of HR 8 is greater than that of 9, 0200 is turned ON; if the
two contents are equal, 0201 is turned ON; if content of HR 8 is less than
that of HR 9, 0202 is turned ON. In some applications, only one of the three
OUTs would be necessary, making the use of TR 0 unnecessary. With this
type of programming, 0200, 0201, and 0202 are changed only then CMP(20)
is executed.
CMP(20)
HR 8
HR 9
0000
1905
0200
1907
0202
TR
0
1906
0201
Greater Than
Equal
Less Than
The following example uses TIM, CMP(20), and LE (SR 1907) to produce
outputs at particular times in the timer’s countdown. The timer is started by
turning ON 0000. When 0000 is OFF, the TIM (10) is reset and the second
two CMP(20)s are not executed (i.e., executed with OFF execution condi-
tions). Output 0200 is output after 100 seconds; output 0201, after 200 sec-
onds; output 0202, after 300 seconds; and output 0204, after 500 seconds.
The branching structure of this diagram is important so that 0200, 0201, and
0202 are controlled properly as the timer counts down. Because all of the
comparisons here are to the timer’s PV, the other operand for each CMP(20)
must be in 4-digit BCD.
Precautions
Flags
Example 1:
Saving CMP(20) Results
Example 2:
Obtaining Indications
during Timer Operation
Data Comparison Section 5–14
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