Grounding Requirements; Figure 13: Opto-Isolated Alarm Input Structure - Motorola MTS LiTE Installation, Configuration And Basic Service Manual

• 2 x Form A relay outputs with Common and Normally Open contacts: Available on the junction
panel.
• DOOR alarm: Connected to the Site Controller
NOTICE:
All 15 alarm inputs and Door alarm use the same Alarm Ground. All these alarms and controls
connect directly to the Site Controller (SC).
The Expansion Cabinet only offers the Door alarm feature.
For detailed information, see
X.21, RGPS, and GPS Cabling on page
The following figure shows detailed User Alarms input structure.

Figure 13: Opto-isolated Alarm Input Structure

Alarm
Indication
Debounce / Noice Rejection
3.9

Grounding Requirements

WARNING: The MTS site must meet certain specifications for adequate protection from
lightning induced transients. Proper ground installation methods are outlined in the Motorola
Standards and Guidelines for Communications Sites, R56.
NOTICE: The methods and standards cited in the following paragraphs are typical. Local
codes, statutes, regulations, and standards supersede any information provided.
Use single-point ground method (where each cabinet is grounded to master ground using its own
ground wire). For equipment cabinet, use green (or green-yellow) insulated wire with a minimum size
2
of 16 mm CSA (#5 AWG) for ground wire.
Ground any external -48 V DC power system in accordance with manufacturers instructions and any
applicable local regulations.
NOTICE:
The MTS cabinet is wired to positive earth but the Power Supply Unit inside has a floating DC
ground concept.
You can use different wire colors according to the local standards.
If the specified wire size is not available, use the next-larger available wire size.
During the installation of the cabinet ground wires, check any factory-installed internal ground
connections for tightness.
External Alarm Cabling on page 138
155.
Schmitt
Trigger
RC Filter
and
Vsupply
12VDC
Opto-Isolator
Contact Closure
(External to Alarm Card)
6802800U74-AN
Chapter 3: Site Preparation
User Alarms/Controls,
85