Watlow Series 982 - Manual (Page 14)

2 . 4 WATLOW Series 982 User’s Manual Installation and Wiring, Chapter 2
Wiring
Wiring the Series 982
Wiring options depend on the model number and DIP switch settings.
Check the terminal designation stickers on either side of the controller
and compare your model number to those shown here and with the model
number breakdown on the inside back cover of this manual.
Input-to-output Isolation
The Series 982 uses optical isolation between the analog inputs and the
controller outputs/digital input. This isolation provides a 500VÅ (VAC)
barrier to prevent ground loops when using grounded sensors and/or
peripheral equipment.
Here is a breakdown of the isolation barriers:
• Analog inputs 1 and 2 are grouped together.
• Outputs 1 through 4 and the standard event input are grouped together.
This does not apply to Output 4 when configured as communications.
• The digital communications output (4) is separate from the above
groups.
Power Wiring
100 to 240 VЕ Е (ac), nominal (85 to 264 actual)
Horizontal Package 98 1 C - _ _ _ _ - _ _ _ _
Vertical Package 98 2 C - _ _ _ _ - _ _ _ _
24 to 28 V‡ ‡ (ac/dc), nominal (21 to 30 actual)
Horizontal Package 98 3 C - _ _ _ _ - _ _ _ _
Vertical Package 98 4 C - _ _ _ _ - _ _ _ _
Sensor Installation Guidelines
Thermocouple input: Extension wire for thermocouples must be of the
same alloy as the thermocouple itself to limit errors.
1 0 0
Ω RTD input: Each 1Ω 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).
Maintain isolation between input 1 and input 2 to prevent a ground loop.
A ground loop may cause incorrect readings, dashes across the upper dis-
play or the display of error codes.
fuse
22 21
earth ground
11
L2 L1
+ -
∫
WARNING:
To avoid potential
electric shock, use
National Electric
Code (NEC) safety
practices when
wiring and connect-
ing this unit to a
power source and
to electrical sensors
or peripheral
devices. Failure to
do so could result
in injury or death.
˜
NOTE:
Input-to-output iso-
lation is defeated
when the external
signal conditioner
power supply option
is used to power a
transmitter connect-
ed to input 1.
Figure 2.4 -
Power wiring.
ç
CAUTION:
If high voltage is
applied to the low
voltage unit, irre-
versible damage
will occur.