Advertisement
Purpose of Quality information in the output signal
(iii)
In the output signal, the quality information will affect the control of the device. Table 4.4-2
shows four types of output signal. When the quality information (Quality) of an output signal
issued by a node is indicated as being "NG", it signifies that device control is forbidden. On the
other hand, quality information (Quality) "OK" means that that device control is allowed.
Table 4.4-2 Device status, quality information in the output signal
Note: With regard to the value of 'Quality', we define "OK" as '0' and "NG" as '1' in the
logic operation.
AND interlock operator
When quality information (Quality) is applied to the interlock operator "AND", the "AND"
operator outputs the quality information intact. That is, the output quality information is not
affected by device status (stVal). Table 4.4-3 shows two-input-signals (A, B) and the output
signal for "AND".
Table 4.4-3 Output signals (stVal–Quality) for AND
Input A
(stVal–Quality)
Figure 4.4-5 shows the logic symbol for the interlock operator "AND" with input signals
and an output signal. Figure 4.4-5 can be represented by equations (4.4-11) and (4.4-12).
stVal = stVa(A) • stVa(B)
Quality=(Quality(A)+Quality(B))•(stVa(A)+ Quality(A))
For example, when the interlock operator "AND" has two input signals (0–NG, 0–OK), it
has to generate a signal (0–OK) using the equations (4.4-11) and (4.4-12). This is because the
quality "NG (i.e., 1)" and the quality "OK (i.e., 0)" are entered into the AND operator; the AND
operator produces zero (0) which is defined as "OK" in 'Quality'. A note regarding the values
Output signal
(stVal–Quality)
0–OK
Control forbidden
0–NG
Control forbidden
1–OK
Control allowed
1–NG
Control forbidden
Input B (stVal–Quality)
0–OK 0–NG 1–OK 1–NG
0–OK
0–OK
0–NG 0–OK 0–NG
1–OK
0–OK 0–NG 1–OK
1–NG 0–OK 0–NG 1–NG 1–NG
- 586 -
Meaning
–
–
–
–
–
–
•(stVa(B)+Quality(B))
6F2T0207 (0.01)
(4.4-11)
(4.4-12)
GRE200 (5,6)
Advertisement
