Table of Contents

Site Preparation Guidelines
Environmental Monitoring Functions
Site Requirements

AC and DC Power
Interference Considerations
Equipment Racks
Site Environment
Equipment Rack Ventilation
Power
Network Connections

Site Planning

This chapter describes how to prepare your site for installation of the chassis and discusses the site environment requirements. This chapter contains the following sections:

• Site Preparation Guidelines

• Environmental Monitoring Functions

• Site Requirements

Site Preparation Guidelines

Planning the proper location and layout of your equipment rack or wiring closet is essential for successful system operation. Equipment placed in an inadequately ventilated area can cause system overtemperature conditions. In addition, poor equipment placement can make chassis panels inaccessible and difficult to maintain. Follow these precautions when planning your equipment locations and connections:

• Keep the front of the chassis free from obstructions and away from the exhaust air of other equipment. Remember that electrical equipment generates heat, and ambient room temperature alone might not be adequate to cool equipment to acceptable operating temperatures.

• Secure the placement of all chassis panels, modules, and any module slot fillers. The fan assembly pulls cooling air across the line modules. A loose panel allows too much air to escape and can redirect the airflow away from active line modules.

Warning This unit is intended for installation in restricted access areas. A restricted access area is where access can only be gained by service personnel through the use of a special tool, lock and key, or other means of security, and is controlled by the authority responsible for the location.

Environmental Monitoring Functions

You can maintain normal system operation by identifying and resolving adverse conditions before the system fails by using environmental monitoring and reporting functions. Environmental monitoring functions constantly monitor the internal air temperature of the chassis. Each power supply monitors its own voltage and shuts down if it detects a critical condition within the power supply. The reporting functions retrieve and display the present values of measured parameters. If any of the monitored parameters exceed defined thresholds, the reporting functions display alarms on the console.

The environmental monitoring functions use two levels of status conditions to monitor the system: normal and alarm. The processor monitors the temperature inside the module compartment, and the power supplies use the normal and alarm levels to monitor voltages.

Table 2-1 lists temperature thresholds for the processor-monitored levels:

The power supply monitors its own internal temperature and voltages. The power supply is either within tolerance (normal) or out of tolerance (alarm). If an internal power supply temperature or voltage reaches the alarm level, the output fail LED may be unreliable and the power supply can shut down the system.

Site Requirements

This section contains the following topics:

• AC and DC Power

• Interference Considerations

• Equipment Racks

• Site Environment

• Equipment Rack Ventilation

• Power

• Network Connections

AC and DC Power

The 1300W AC power supply uses a power factor corrector (PFC) that allows the power supply to operate on input voltage and current within the ranges of 90 to 264 VAC and 50 to 60 Hz.

A second, identical power supply is also present in the chassis configured with an optional redundant power supply. Table A-1 in the appendix "Chassis and Power Supply Specifications" lists system power specifications, including input voltage and operating frequency ranges.

The Catalyst 8540 relies on protective devices in the building installation for protection against short-circuit, overcurrent, and earth fault. Ensure that the protective devices in the building installation are properly rated to protect the system, and that the protective devices comply with national and local codes.

The following warnings apply to DC power supplies:

Warning A readily accessible two-poled disconnect device must be incorporated in the fixed wiring.

Before connecting each unit, note its power consumption rating in Table A-1 in the appendix "Chassis and Power Supply Specifications."

Interference Considerations

When wires are run for any significant distance in an electromagnetic field, interference can occur between the field and the signals on the wires. As a result:

• Bad plant wiring can result in radio frequency interference (RFI).

• Strong electromagnetic interference (EMI), especially when it is caused by lightning or radio transmitters, can destroy the signal drivers and receivers in the chassis, and can even create an electrical hazard by conducting power surges through lines and into equipment.

Equipment Racks

A rack-mount kit is provided for mounting the chassis in a standard 19-inch (48 cm) equipment rack. The rack-mount kit is not suitable for racks with obstructions (such as a power strip) that could impair access to the processor and power supplies. Figure 2-1 shows the chassis footprint and outer dimensions.

Figure 2-1: Chassis Footprint and Outer Dimensions

To use the rack-mount kit, your equipment rack must meet the following requirements:

• The width of the rack, between the two front mounting strips or rails, must be 17.75 inches (43.13 cm).

• The depth of the rack, between the front and rear mounting strips, must be at least 19.25 inches (48.2 cm) but not more than 32 inches (80 cm).

• The height of the chassis is approximately 25 inches (62.5 cm). The rack must have sufficient vertical clearance to allow insertion of the chassis.

When planning your rack installation, follow these guidelines:

• Allow at least 3 feet (1 m) of clearance in front of the rack for maintenance and removal of the route processor, line modules, power supplies, and the fan assembly.

• Note that the ports for cooling air are located on the front, rear, and both sides of the chassis, so multiple chassis can be rack-mounted with little or no vertical clearance. However, avoid placing the chassis in an overly congested rack.

Warning To prevent overheating the chassis, do not operate it in an area that exceeds the maximum recommended ambient temperature of 104ºF (40ºC). To prevent airflow restriction, allow at least 3 inches (7.6 cm) of clearance around the ventilation openings.

• Consider the equipment and cabling already installed in the rack. Ensure that cables from other equipment do not obstruct the airflow through the chassis or impair access to the power supplies or line modules. Route cables away from field-replaceable components to avoid having to disconnect cables unnecessarily to perform equipment maintenance or upgrades.

• Install heavier equipment in the lower half of the rack to maintain a low center of gravity.

• Ensure that the shelf you place the chassis on can support the weight and dimensions of the chassis. Use the chassis footprint, shown in Figure 2-1 if you are designing a customized shelf.

Caution Never install the chassis in an enclosed rack that is not properly ventilated or air-conditioned.

Follow these guidelines to help ensure your safety:

• Mount the chassis at the bottom of the rack.

• If the rack has stabilizing devices, install the stabilizers before mounting or servicing the unit in the rack.

• The chassis must always be mounted horizontally, as shown in Figure 2-2 .

In addition to the preceding guidelines, review the precautions in the section "Equipment Rack Ventilation" later in this chapter.

Figure 2-2: Installing the Chassis in the Rack

Site Environment

The chassis operates as a standalone system mounted in a rack in a secure wiring closet. The environment must be dry, clean, well-ventilated, and air-conditioned. An internal fan assembly pulls cooling air through the chassis from the front and right side (intake) to the rear and left side (exhaust). (See Figure 2-3 .) The flow of ambient air must be maintained to ensure normal operation. If the airflow is blocked or restricted, or if the intake air exceeds 104ºF, an overtemperature condition can occur. Under extreme conditions, the environmental monitor can shut down the system to protect the system components.

Figure 2-3: Internal Airflow

To ensure normal operation and avoid unnecessary maintenance, plan your site configuration and prepare your site before installation. After installation, make sure that the site maintains an ambient temperature of 32 to 104ºF (40ºC), and that the area around the chassis is free of dust.

Multiple chassis can be rack-mounted with no clearance above and below the chassis. When mounting a chassis in a rack with other equipment or when placing a chassis on the floor adjacent to other equipment, ensure that the exhaust from other equipment does not blow into the intake vent (lower front panel) of the chassis.

Table 2-2 lists the operating and nonoperating environmental site requirements. To maintain normal operation and ensure high system availability, maintain an ambient temperature at your site. The chassis operates in the ranges listed in Table 2-2; however, a measurement that is approaching the minimum or maximum of a range indicates a potential problem. You can maintain normal operation by anticipating and correcting environmental anomalies before they exceed the maximum operating range.

Equipment Rack Ventilation

If you plan to install the chassis in an equipment rack, follow these precautions and guidelines that are provided in the section "Equipment Racks" earlier in this chapter to avoid overtemperature conditions:

• Install the chassis in an enclosed rack only if it has adequate ventilation or an exhaust fan. Use an open rack whenever possible.

• Note that a ventilation system that is too powerful in a closed rack might prevent cooling by creating negative pressure around the chassis and redirecting the air away from the chassis intake vent. If necessary, operate the chassis with the rack open.

• Use baffles inside the enclosed rack to assist in cooling the chassis.

• Do not place equipment near the bottom of a rack, because it might generate excessive heat that is drawn upward and into the intake ports of equipment above, leading to overtemperature conditions in the chassis at or near the top of the rack.

Power

Follow these precautions when planning power connections to the chassis:

Warning The device is designed to work with TN power systems.

• Install proper grounding to avoid damage from lightning and power surges.

• Connect redundant power supplies to separate input power lines. Install a second source for redundant power if a separate line is not already in place.

Warning Care must be given to connecting units to the supply circuit so that wiring is not overloaded.

Network Connections

When preparing your site for network connections to the chassis, consider these factors related to each type of interface:

• Type of cabling required for each type (fiber-optic, coaxial, or twisted-pair cabling)

• Distance limitations for each signal type

• Specific cables you need to connect each interface

• Any additional interface equipment you need, such as transceivers, modems, channel service units (CSUs), or data service units (DSUs)

Before installing the chassis, make sure all the additional external equipment and cables are on hand.

Posted: Thu Sep 2 10:12:06 PDT 1999
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