MAN0927-03 PAGE 5 Thermocouple module
5
INSTALLATION / SAFETY
Warning:
Remove power from the OCS controller, CAN port, and any peripheral equipment
connected to this local system before adding or replacing this or any module
a) All applicable codes and standards should be followed in the installation of this product.
b) Shielded, twisted-pair wiring should be used for best performance.
c) Shields are to be terminated to frame ground.
d) In severe applications, shields should be tied directly to the ground block within the panel.
e) Ungrounded thermocouple sensors are preferred due to their isolated electrical
characteristics
f) Interposing terminal strips between the sensor and the module can cause errors due to cold
junction effect.
g) If Interposing terminal strips must be used, use specially constructed terminal blocks, which
match the material characteristics of the thermocouple sensor.
h) Horner thermocouple input modules use a high impedance differential circuit to support the
use of grounded or ungrounded thermocouples. For grounded thermocouples, the specified
Common Mode Range
allows for ground potential differences between the machine ground
and the PLC ground within that range. For ungrounded or floating thermocouples the high
impedance inputs are subject to common mode noise pickup. For noisy environments it is
recommended that one side of all ungrounded thermocouples be grounded near the PLC.
This does not affect open thermocouple detection or measurement accuracy and reduces the
effect of common mode noise if present. This PLC side ground connection must not be used
with grounded thermocouples or accuracy will be affected. Any thermocouple should be
grounded in one place at most.
When found on the product, the following symbols specify:
•
All applicable codes and standards need to be followed in the installation of this product.
•
For I/O wiring (discrete), use the following wire type or equivalent: Belden 9918, 18 AWG or
larger.
Warning:
Consult user documentation.
Warning:
Electrical Shock Hazard.
WARNING:
To avoid the risk of electric shock or burns, always connect the safety (or
earth) ground before making any other connections.
WARNING:
To reduce the risk of fire, electrical shock, or physical injury it is strongly
recommended to fuse the voltage measurement inputs. Be sure to locate fuses as close to
the source as possible.
WARNING:
Replace fuse with the same type and rating to provide protection against risk of
fire and shock hazards.
WARNING:
In the event of repeated failure, do not replace the fuse again as a repeated
failure indicates a defective condition that will not clear by replacing the fuse.
WARNING:
Only qualified electrical personnel familiar with the construction and operation
of this equipment and the hazards involved should install, adjust, operate, or service this
equipment. Read and understand this manual and other applicable manuals in their entirety
before proceeding. Failure to observe this precaution could result in severe bodily injury or
loss of life.
