The “pound” symbol (#) is absolutely necessary to identify the field as
a “bit-state field.”
5. Press the
End Data key. The bit-state field you have just created con-
sists of seven spaces in all, which is the maximum number of spaces
allowed for such a field. In LIVE DISPLAY MODE, a bit-state field will
display one of two predesignated
words describing the two possible
states of the bit.
6. Move the cursor down two lines, and type “
BIT 899.” Then press the
Begin Data key.
7. Type three spaces, followed by
#899
8. Press the Exit key to leave TEXT EDITOR MODE and return to LIVE
DISPLAY MODE. Since Bit Nos. 898 and 899 should each be at a
“Logic 0” state, the word “
LOW” should appear in each of the two bit-
state fields you have just created, with
red characters on a white back-
ground
.* When either bit changes its state from “Logic 0” to “Logic 1,”
its field should read “
HIGH” with white characters on a black back-
ground
.
The word pair “HIGH/LOW” is the initially specified “BIT DESIGNATOR
PAIR” for all system logic bits, with the abovementioned color combi-
nation for each word. You can easily change the words and colors
used to display any bit, using the
BIT STATE DISPLAY (BSD) and BIT
DESIGNATOR PAIR (BDP)
commands as explained in Section 2.C.12
of the
System 10 Guidebook.
9. Save the page you have just formatted, as you did in Section 5, Step l.
In Section 12.a, above, you used the
SRC command to assign a logic source
of “LATCHING LIMIT LOGIC” to Bit No. 898. Now you will cause this bit to be
set and latched on the occurrence of a HIGH-LIMIT violation for Channel No. x.
j. To cause Bit No. 898 to be set and latched to a state of “Logic 1” when the
data value for Channel No. x exceeds the high-limit value specified by the
above
HIL command, enter a command of
LGT x = 898 [CR]
Note that we could just as well have arranged for Bit No. 898 (or any other
system bit) to “go high” when Channel No. x’s data reading drops below
the low-limit value specified by the
LOL command, or when it re-enters the
channel’s “OK” (“BETWEEN”) zone after either a high-limit or low-limit vio-
lation has occurred. See Section 2.F.4 of the
System 10 Guidebook for a
complete discussion of the three “LIMIT LOGIC” commands (
LGT, LLT,
and
LBT).
k. Verify the effectiveness of the above
LGT command by producing an
approximately full-scale transducer input for Channel No. x and observing
the resultant display of Bit No. 898 (it should now read “HIGH”).
l. Decrease the transducer load until it is less than the high-limit value, but
higher than the low-limit value. Since Bit No. 898 is latched, it should con-
tinue to display the word “HIGH.”
B - 28
LIMIT SETUP
“O
NTHE
A
IR
” (B-S
IZED
)
*For a monochrome display, black characters on a white background.
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