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MELSEC-A
6 TROUBLESHOOTING
<Sample calculation for example 1>
AJ65MBTL1N-16D
CC-Link
embedded
input
adapter
24 V DC
4.7 k
Leakage
current
2.45 mA
When a 2.45 mA leakage current flows due
to a switch with LED indicator connected to
the AJ65MBTL1N-16D.
•
The voltage V
TB
across the terminal and common is obtained by the following
expression.
V
TB
= 2.45 [mA] 5.1 [k ] = 12.5 [V]
(The voltage drop across the LED is ignored.)
Since this result does not satisfy the OFF voltage of 6 [V] or less, the input
signal does not turn off. Hence, connect a resistor as shown below.
R
AJ65MBTL1N-16D
Input impedance
5.1 k
4.7 k
24 V DC
Current I
•
Calculation of resistor R value
Current I should be as follows so that the terminal voltage of the
AJ65MBTL1N-16D is 6 [V] or less.
(24 6 [V] ) 4.7 [k ] = 3.83 mA
Therefore, connect a resistor R that will give a current I of 3.83 mA or more.
•
Resistor R to be connected is as follows.
6 [V] R > 3.83
6 [V]
5.1 [k ]
6 [V] R > 3.83 1.18 [mA]
6 [V] 2.65 [mA] > R
2.26 [k ] > R
Assuming that resistor R is 2.2 k , the power capacity W of the resistor when
the switch turned on is as follows.
W = (applied voltage)
2
/R
W = (26.4 [V] )
2
/2.2 [k ] = 0.32 [W]
•
The power capacity of the resistor is 1 to 2 [W] since a factor of 3 to 5 as
compared to the actual power consumption is used to select the power
capacity.
Accordingly, connect a 2.2 [k ], 1 to 2 [W] resistor across the corresponding
terminal and COM.
Summary of Contents for CC-Link
Page 1: ...CC Link Embedded I O Adapter User s Manual ...
Page 2: ......
Page 13: ...1 5 1 5 MELSEC A 1 OVERVIEW MEMO ...
Page 17: ...3 2 3 2 MELSEC A 3 SPECIFICATIONS MEMO 3 ...
Page 43: ......
