Watlow Electric Revision 5 - Manual (Page 37)

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Alarm outputs are also used to activate SSR's when possible. The connections are
essentially the same.
Lower Terminal Block TB2
SSR 1 SSR 2
|--------| |--------|
Pin | - + | | - + |
|--|--|--| |--|--|--|
Low Dev. Out 1 5 O--------------| | | |
| | |
High Dev. Out 2 6 O-----------------|------------| |
| |
+5V 11 O-----------------o---------------|
6.1.1 PROCESSOR READY
The processor READY is a Watchdog Timer Output from the PIOM and is
an indication that the microprocessor is running its program. This output is
available at READY Pin #33 of the TB2 on the PROCESSOR I/O
MODULE (PIOM).
This output is on [will sink current] whenever the microprocessor is
functioning properly. The READY output takes about 2 seconds upon
power up to indicate ready. The output is an open collector NPN transistor
to ground, capable of sinking 15ma. Maximum ratings of 24vdc at 25ma
should not be exceeded.
To use the READY output as a TTL signal, connect a 4.7Kohm resistor
from the +5v supply Pin #31 to READY Pin #33 of TB2. Pin #33 will be
TTL low(0v) with respect to ground Pin #32, when the processor is ready or
running. Pin #33 will be TTL high(5v), when the processor is not
functioning.
TTL output for Processor Ready
+ 5vdc 31 O------
Ground 32 O--------------------O TTL Output: 0v = OK
4.7 K 5v = Problem
Ready 33 O--------------------O
To use the READY output to energize a relay, an optically- isolated solid-
state relay [SSR] is recommended. The control signal is +5v. Connect the
positive terminal of the SSR to Pin #31 and the negative terminal to Pin
#33. When the microprocessor is ready, the relay will be energized. Upon
failure of the microprocessor, the relay would be de-energized. A Gordos
#OAC5A or #G280D10 equivalent is recommended.
Processor Ready output connected to SSR