Section 1:
Introduction
Page 7
How the Bit Status field functions when Entry Allowed is selected:
Assume the results of example one, the field is currently displaying
[STOP]
. Further assume you use the
Select
key
on the 2800 to assign focus to this field then press the
Enter
key.
Drive Value
0000 0000 0000 0001
AND with compliment of Mask Value
1111 1111 1111 1110
Formula 1
write this value to the Drive
0000 0000 0000 0000
2800 reads Drive Value back
0000 0000 0000 0000
2800 ANDs it with Mask Value
0000 0000 0000 0001
Results
0000 0000 0000 0000
Result does not match Data Value so the field text will change to
[START]
.
Lets try the opposite case. Assume the results of example two, the field is currently displaying
[START]
. You use
the
Select
key on the 2800 to assign focus to this field then press the
Enter
key.
Assumed PLC Value
0000 0000 0000 0000
AND with compliment of Mask Value
1111 1111 1111 1110
Formula 2
Results
0000 0000 0000 0000
OR with Data Value
0000 0000 0000 0001
write this value to the PLC
0000 0000 0000 0001
2800 reads PLC Value back
0000 0000 0000 0001
2800 ANDs it with Mask Value
0000 0000 0000 0001
Results
0000 0000 0000 0001
Result does match Data Value so the field text will change to
[STOP]
.
PM2800U3K Revision 4
