Function Blocks UM353-1
March 2003
3-24
An alarm status word is shown below.
A_=1 when the alarm is active
N_=1 when the alarm is Not acknowledged
E_=1 when the alarm is enabled (when the alarm is disabled the E, N, and A bits are set to 0)
OS=1 indicates that all alarms are identified as Out of Service which means that all alarms function normally but the
OS flag indicates to a higher level device that they can be ignored. OS cannot be set locally.
CC=1 indicates a configuration change has occurred. It can be reset by a write command.
AE=1 indicates an Active Event is present within the loop. It will clear when all the loop events clear.
NA will be set to 1 when events occur and at least one within the loop has not yet been acknowledged. It can be
reset to 0 which will acknowledge all events within the loop or when 0 will indicate all active events have been
acknowledged
BIT 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
1
AE NA CC OS E4 N4 A4 E3 N3 A3 E2 N2 A2 E1 N1 A1
0
3.2.13 AND_ - AND Logic
AND_ function blocks perform a logical AND on the three
inputs. Any unused input will be set high (1).
Input
A
AND
O1
O
utput
1
AND
AND_
ESN =
000
A
ESN
E
xec.
S
eq.
N
o.
(H)
................ 001 to 250
C
TU
P
N
I
INPUT B
(H)
..........
loop tag.block tag.output (null)
Input
B
B
B
TU
P
N
I
INPUT C
(H)
..........
loop tag.block tag.output (null)
Input
C
C
A
TU
P
N
I
INPUT A
(H)
..........
loop tag.block tag.output (null)
BLOCK DIAGRAM
A
O1
B
C
AND TRUTH TABLE
AB CO
utput
1
0000
00
0
0
0
00
0
0
1
1
11
0
0
0
0
0
0
1
1
1
1
1
1
111
AND
.
.