High-Speed Contact Sense; Contact Operate - IBM 1710 Manual

High-Speed Contact Sense
High-Speed Contact Sense, available as a special
feature, gives the 1710 the ability to determine the
status of on/off conditions in the process area. It is
especially suited for control system applications that
require very fast sensing of process contacts and for
reading the many types of contacts used in industrial
processing. Contact sense points are available in incre-
ments of five, with a maximum of 400 on anyone
system.
Description
Contact sense points are terminated in blocks of 50
points each. One terminal address is assigned for a
group of 20 terminal points. A total of 20 terminal
addresses is available if all 400 contact sense points are
installed. For the purposes of programming, the ter-
minal block can be thought of as consisting of two
parts with 200 terminal points
(lO
terminal addresses)
on each part. When a program instruction specifies
anyone of the 10 terminal addresses on either part, the
20 terminal points at that address and all of the
terminal points tor the remaining higher-numbered
terminal addresses tor that part are scanned and read
into core storage. For example, in the following chart
of terminal addresses it can be seen that an instruction
specifying terminal address 03 causes the program to
scan and read into core storage terminal points 60
through ] 99.
Terminal Points Terminal Points
Addresses Scanned Addresses Scanned
00 000-199
]0
200-399
01 020-199
11
220-399
02 040-199
]2
240-399
03 060-199
]3
260-399
04 080-199 14 280-399
05 ] 00-199 15 300-399
06 120-199 16 320-399
07 ] 40-199 17 340-399
08 ] 60-199 18 360-399
09 180-199 19
380-399
As another example, terminal address 10 would
cause the program to scan and read into core storage
terminal points 200 through 399; thus, up to 200
terminal points can be read with one instruction.
Contact points are scanned and read into core stor-
age at the rate of 100,000 points per second. When
fewer than 200 points are scanned, the rate is less than
100,000 points per second.
18
Table 1 contains examples of actual scanning rates.
The program instruction associated with the High-
Speed Contact Sense special feature is Select Contact
Block.
Table I. Examples of High-Speed Contact Sense Scanning Rates
Number of
Number of
Time in
Scanning Rate
Points
Computer
Microseconds
in Points
Scanned
I nstruct ions
per Second
20 1 335 59,000
100 1
1,035
96,000
200 1
1,910 105,000
400
2 3,820
105,000
Contact Operate
The Contact Operate feature enables the 1710 to con-
trol on/off conditions in the process area. Motor start-
ups, annunciators, horns, alarms - any device which
can be controlled by a momentary contact closure may
be programmed.
Contact Operate functions are available in incre-
ments of two. They may be terminated on the same
terminal block with Analog Output functions, but not
with Analog Input. The special feature, Random Ad-
dressing of
TAS)
is required. Contact Operate utilizes
mercury-wetted relay switches for its operation.
Application
A simplified Contact Operate circuit is shown in Figure
] 0 to point out the following:
]. Customer power is used to operate a customer's
device (an alarm in this case) - the Contact Oper-
ate function merely completes the circuit. The
contact capacity is 100 volt-amperes with a 2-am-
pere, 120-volt
AC
or 24-volt
DC
maximum. Note
that the contact lines are fused within the 17] 2.
2. The customer's relay is energized when the Con-
tact Operate instruction is executed. The relay
contact R-l closes and the alarm is activated.
3. The customer relay circuit mayor may not be
self-latching. The relay shown is latched, that is,
held energized by its R-2 points. An unlatching
method such as a push button may be provided
by the customer.
4. Adequate arc suppression must be provided by
the customer for contact protection. For addi-
tional information, refer to
IBM
1710 Control Sys-
tem Installation Manual - Physical Planning
(Form C26-5605) .