PDP11 PeripheralsHbk 1972 - Trailing-Edge
PDP11 PeripheralsHbk 1972 - Trailing-Edge
PDP11 PeripheralsHbk 1972 - Trailing-Edge
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c. Output Driver Module BW403 . Is similar to the BW402 Common Power Mod·<br />
ule except that a common ground return is provided for the open collector de·<br />
vices of the Single Shot Driver and Flip·Flop Driver. (used with BW85 and<br />
BW87 only)<br />
d. Contact Sense BW731 . Provides electrically isolated, differential inputs for 16<br />
external customer contacts or voltages. Isolation of up to 250 volts is achieved<br />
by a miniature read relay buffer on each input point. This module provides reo<br />
liable and trouble free digital sensing in high noise environments. Also, its dif·<br />
ferential input characteristics are particularly suited for those applications<br />
where the ground of the customer's excitation voltage power supply may be<br />
different from (i.e., not directly strapped to) computer system ground.<br />
e. Contact Interrupt BW733 - provides 16 electrically isolated, differential inputs<br />
for external customer contacts or voltages. It is electrically and mechanically<br />
similar to the BW731 Contact Sense Module. The BW733 is used to economically<br />
and reliably interface asynchronous devices requiring fast service from the<br />
processor because of priority or short duration.<br />
9.4.5 Functional I/O Modules<br />
a. Flip Flop Driver BM685 - Provides 16 solid state buffered driver circuits for<br />
control of solenoid valves, relays, lamps, displays, etc. Capable of switching<br />
control voltages of up to + 55 VDC, the BM685 will switch up to 250 ma of<br />
field supplied power per point, when set by a logical "I." The driver includes<br />
diode protection for inductive loads.<br />
b. Single Shot Relay BM807 - provides 16 electrically isolated normally open mercury<br />
wetted contact ouputs for initiating alarms, controls, and field relays.<br />
Normally closed operation can be achieved through a module jumper change<br />
performed in the field by the customer or at the factory on a special order<br />
basis. The duration of the output is trimpot adjustable from 2 msec to 2 seconds.<br />
A logical "I" energizes the relay coil for the pre· set pulse duration.<br />
C. Single Shot Driver BM687 - Provides a solid state pulse output to activate up<br />
to 16 field circuits such as lights, buzzers, or external control relays. Capable<br />
of switching control voltages of up to + 55 VDC, the BM687 will switch up to<br />
250 ma of field supplied power per point, when set by a logical "1." The driver<br />
also provides diode protection against inductive loads.<br />
d. Latching Relay BM803 - Provides "fail-safe" operation of 16 electrically iso·<br />
lated mercury wetted relay outputs. Magnetically latched, the relays remain<br />
set in the event of power failure, insuring the continuity and integrity of field<br />
circuits. Change of state can be effected only by a logical "1" or "0." Relay<br />
contacts are open when the relay is set by a logical "0, "and closed when set<br />
by a logical "1." Contacts are rated at 2 amps, 250 volts, the product not to<br />
exceed 100 va.<br />
e. Flip Flop Relay BM805 - Provides 16 electrically isolated normally open mercury<br />
wetted relay output contacts for buffered control of relays, contactors,<br />
displays, lamps, etc. Normally closed operation is possible by a module jumper<br />
change performed in the field by the customer or at the factory on a spe·<br />
cial order basis.<br />
f. BW734 Counter Module - Is a 10 bit asynchronous binary up counter. An output<br />
buffer register is included which is updated after each counter increment.<br />
When the buffer is read (under program control), the update is inhibited, pre-<br />
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