Chapter 8: Installation and Wiring
Do-more T1H Series PLC User Manual, 1st Edition, Rev. C
8-7
4. There must be a minimum of 2” (50mm) clearance between the panel door and the nearest
Terminator component.
5. The ground terminal on the Terminator power supply must be connected to a single point
ground. Use copper stranded wire to achieve a low impedance. Copper eye lugs should be
crimped and soldered to the ends of the stranded wire to ensure good surface contact. Remove
anodized finishes and use copper lugs and star washers at termination points. A general rule is
to achieve a 0.1 ohm of DC resistance between the Terminator I/O slave and the single point
ground.
6. There must be a single point ground (i.e. copper bus bar) for all devices in the panel requiring
an earth ground return. The single point of ground must be connected to the panel ground
termination. The panel ground termination must be connected to earth ground. For this
connection you should use 12AWG stranded copper wire as a minimum. Minimum wire sizes,
color coding, and general safety practices should comply with appropriate electrical codes and
standards for your region. A good common ground reference (earth ground) is essential for
proper operation of the Terminator system. There are several methods of providing an adequate
common ground reference, including: a) Installing a ground rod as close to the panel as possible.
b) Connection to incoming power system ground.
7. Properly evaluate any installation where the ambient temperature may approach the lower or
upper limits of the specifications. Place a temperature probe in the panel, close the door and
operate the system until the ambient temperature has stabilized. If the ambient temperature is
not within the operating specification for the Terminator system, measure points in the panel in
consideration for installing a cooling/heating source to provide the ambient temperature to meet
the Terminator I/O operating specifications.
8. Device mounting bolts and ground braid termination bolts should be #10 copper bolts or
equivalent. Tapped holes instead of nut-bolt arrangements should be used whenever possible.
To assure good contact on termination areas impediments such as, paint, other coating or
corrosion should be removed in the area of contact.
9. The system is designed to be powered by 110/220 VAC or 24VDC normally available
throughout an industrial environment. Isolation transformers and noise suppression devices are
not normally necessary, but may be helpful in eliminating/reducing suspect power problems.
Enclosures
Your selection of a proper enclosure is important to ensure safe and proper operation of your
Terminator system. Applications of Terminator systems vary and may require additional
features. The minimum considerations for enclosures include:
•
Conformance to electrical standards
•
Protection from the elements in an industrial environment
•
Common ground reference
•
Maintenance of specified ambient temperature
•
Access to equipment
•
Security or restricted access
•
Sufficient space for proper installation and maintenance of equipment
