Function Blocks
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
1
AE
NA
CC
OS
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).
A
B
C
.
AND TRUTH TABLE
A
B
0
0
0
0
0
1
0
1
1
0
1
0
1
1
1
1
BLOCK DIAGRAM
3-24
11
10
9
8
E4
N4
A4
E3
AND
O1
.
C
Output 1
0
0
1
0
0
0
1
0
0
0
1
0
0
0
1
1
7
6
5
4
3
N3
A3
E2
N2
A2
AND
AND_
ESN = 000
Input A
A
AND
Input B
B
C
Input C
I
N
P
U
T
A
INPUT A
(H)
I
N
P
U
T
B
INPUT B
(H)
N
U
T
I
P
C
INPUT C
(H)
E S N
Exec. Seq. No.
UM353-1
2
1
0
E1
N1
A1
O1
Output 1
..........
loop tag.block tag.output
(null)
..........
loop tag.block tag.output
(null)
..........
loop tag.block tag.output
(null)
................ 001 to 250
(H)
March 2003