Watlow Series 96 - Manual (Page 7)

Chapter Three
Wiring
Input-to-Output Isolation
Figure 3.1a Isolation blocks.
Power Wiring
100 to 240VÅ (ac), nominal (85 to 264 actual) 96 A _ - _ _ _ _ - _ _ _ _
24 to 28V‡ (ac/dc), nominal (21 to 30 actual) 96 B _ - _ _ _ _ - _ _ _ _
Figure 3.1b Power wiring.
Sensor Installation Guidelines
Thermocouple inputs: Extension wire for thermocouples must be of the same
alloy as the thermocouple to limit errors.
When using a process signal (4-20mA, 0-5VÎ [dc], etc.) for the remote set point
or a voltage input for the digital input 2, use an ungrounded or isolated
thermocouple. If a grounded thermocouple is required, the signal to input 2 must
be isolated to prevent possible ground loops.
RTD input: Each 1
Ω
of lead wire resistance can cause a +2°F error when using
a two-wire RTD. A three-wire RTD sensor overcomes this problem. All three
wires must have the same electrical resistance (i.e., same gauge, same length,
multi-stranded or solid, same metal).
Process input: Isolation must be maintained between input 1 and input 2. If
both input 1 and input 2 are process signals, a separate power supply and
transmitter must be used for each input. These inputs must be electrically
isolated from one another to prevent ground loops.
Fuse
L2
L1
-
8
9 +
10
8 1
2
3
4
5
6
7
13 14 15
11
12
16 17 18
19 20 21
9
Isolation Blocks
There are no electrical connections between these blocks.
Output 1
Output 2
Output 3
Output 4 (unless Output 4
is used for communications) Input 1
Input 2 Output 4 (if Output 4 is
used for communications)
3
Wa t l o w S e r i e s 9 6 W i r i n g ■ 3 . 1
NOTE:
It is advisable to check
Output 1-4 hardware.
These outputs may differ
from those listed for the
model number on the
controller and described
in this manual,
indicating a customized
hardware setup.
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CAUTION:
If high voltage is applied
to a low-voltage unit,
irreversible damage will
occur.
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WARNING:
To avoid damage to
property and equipment,
and/or injury of loss of
life, use National
Electric Code (NEC)
standard wiring practices
to install and operate the
Series 96. Failure to do
so could result in injury
or death.
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CAUTION:
Maintain isolation
between input 1 and
input 2 to prevent a
ground loop. A ground
loop may cause incorrect
readings, dashes across
the upper display or the
display of error codes.
Failure to follow this
guideline could result in
damage to equipment
and product.