Watlow Controls 8LS, Руководство пользователя

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14 8LS User’s Guide
Installation
2. Use 20 or 22 AWG size wire. The use of 16,18,20,22, or 24 AWG is
permissible also. The power requirement is not a factor in the wire
size. Only the mechanical strength and the ohmage of the wire may
be factors to consider. Smaller or larger sizes are not easily
installed, may be easily broken and/or cause intermittent connections.
3. Use shielded wire. The electrical shield is used primarily to protect
from unwanted electrical noise.
Normal use of the input wiring shield is to connect one end only to
the 120 VAC panel ground at the 8LS panel location. Another method
is to connect it at the sensor site ground and to the Analog Ground
terminal of the 8LS.
Normal use of the output wiring shield would be to connect one end
only to the 120 VAC panel ground in the panel that the 8LS is
mounted in. Actual use of the shields will be determined by the
installation requirement.
For additional noise suppression measures see NOISE SUPPRES-
SION FOR Digital Outputs.
4. Use Thermocouple Extension Wire for all thermocouple (T/C)
inputs. Most T/C Ext. Wire is solid wire unshielded. When using
such, the shield function cannot be utilized and only 16, 18, or 20
AWG should be used. Install all T/C wiring in its own conduit away
from AC Power and High Power wiring. Depending on type and wire
size up to 400-500 feet in length may be used to be within stated
accuracy and source impedance.
5. Use multiconductor stranded shielded cable for analog inputs. Most
inputs will use a shielded twisted pair, but some may require a 3 wire
input. Run all analog input wiring in its own conduit away from AC
Power and High Power wiring. Wire sizes of 20, 22, or 24 AWG may
be used.
6. Use multiconductor stranded shielded cable for analog outputs and
PID digital outputs connected to panel mount SSR's. The analog
output will normally use a twisted pair while the digital outputs will
be up to 9 or 20 conductors depending on wiring techniques. All
cables will be shielded. The wiring size will normally be 24 AWG.
The maximum length for the digital outputs should not exceed 25
feet. The maximum length for the analog outputs should not exceed
400 feet. All wiring must be in a separate conduit away from AC
Power and High Power wiring.
When using the 50 conductor flat ribbon cable for the I/O, use of
the 50-pin connector is recommended for both ends of the cable.
The wire is too small to withstand much flexing when connected to
a screw terminal. The cable length should not exceed 15 feet.
7. When installing communications wiring, by pulling in an extra pair, a
sound power phone system could be used for communications
between the 8LS and the computer. This could be used for mainte-
nance, checking calibration and many other functions. A David Clark
#H5030 sound powered system has been used successfully in sys-
tems requiring this function.
8. When installing any I/O wiring to the 8LS inside a panel, it should
never be run in the same bundle as AC power wiring.