Power Requirements
Cisco TelePresence systems—especially the larger models such as the CTS-3000 and CTS-3200—have unique power requirements that must be taken into account during the room evaluation and design phase. The chances of your room already containing the correct type and quantity of electrical circuits and receptacles are slim. Therefore, the services of a qualified electrician will be required for every room you deploy.
First, take the amount of wattage consumed by the system to ascertain the quantity and amperage of electrical circuits required to power the equipment. These calculations were provided previously in Tables 8-6, 8-7, and 8-8.
Now that you know the total wattage and total amperage required by the system, you can ascertain the number of circuits and amperage per circuit. Cisco TelePresence systems are rated for 10amps@240v or 20amps @120v. Electrical codes in use suggest that only 80 percent of a circuit's capacity should be used. Therefore, on a 20-amp circuit running at 120v in the U.S., only 16 amps of it are useable, and on a 10-amp circuit running at 240V in Europe, only 8 amps are useable. Therefore, a CTS-3000 for example that requires a total of 54amps@120V, divided by 16amps per circuit, requires a minimum of four 16amp circuits on the wall.
The components are attached to Power Distribution Units (PDU). Each PDU, in turn, is attached to one of the power circuits on the wall. The CTS-3000 requires four PDUs. Table 8-10 shows which of the four PDUs each component is attached to and, hence, how the power is distributed across the circuits.
Table 8-10. Power Distribution for CTS-3000
|
Component |
PDU #1 |
PDU #2 |
PDU #3 |
PDU #4 |
|
Three 65-in. Plasma Displays |
1 @ 960 Watts |
1 @ 960 Watts |
1 @ 960 Watts |
|
|
One Primary Codec |
1 @ 120 Watts |
|||
|
Two Secondary Codecs |
1 @ 108 Watts |
1 @ 108 Watts |
||
|
Three Lighting Façade Fixtures (Top) |
1 @ 80 Watts |
1 @ 80 Watts |
1 @ 80 Watts |
|
|
Two Lighting Façade Fixtures (Sides) |
1 @ 54 Watts |
1 @ 54 Watts |
||
|
One Projector |
1 @ 288 Watts |
|||
|
(optional) Auxiliary LCD displays |
1 @ 240 Watts |
1 @ 240 Watts |
1 @ 240 Watts |
|
|
(optional) WolfVision document camera |
1 @ 200 Watts |
|||
|
Six Participant A/C power jacks in table legs |
6 @ 240 Watts each |
|||
|
Total Watts |
1442 Watts |
1600 Watts |
1442 Watts |
1728 Watts |
|
Amperage Required |
12.02A @ 120V or 6.01A @ 240V |
13.34A @ 120V or 6.67A @ 240V |
12.02A @ 120V or 6.01A @ 240V |
14.4A @ 120V or 7.2A @ 240V |
Again, remember that things can change from one product release to another, so the information in Table 8-10 is given as an example and is highly subject to change. For instance, when Cisco first released the CTS-3000, only four dedicated circuits were needed, and the light façade was connected to the same circuits as the other components. But that meant that the light façade remained on 24 hours a day, 7 days a week. To improve this, Cisco Technical Marketing came out with a recommendation that the light façade be connected to a fifth switched electrical circuit that was controlled by the same switch on the wall that controlled the overhead/ceiling lights in the room, and Cisco manufacturing started including a fifth PDU in every CTS-3000 shipment to facilitate customers doing this. However, because most ceiling light fixtures operate at 277V, additional electrical conditioning components were required to extend a receptacle of that circuit to the wall behind the system so that the light façade could be plugged into it. Now, at the time of this writing, Cisco is coming out with a third, better option—a separate, custom-designed PDU called the Auxiliary Control Unit (ACU), which is attached to a fifth dedicated circuit. The ACU is controlled by the Primary Codec and controls the individual receptacles on the ACU to turn the light façade on/off automatically. The system can be configured to turn the lights on/off per call, or on at the beginning of business hours (by default, at 7 a.m. local time) and off after business hours (by default, at 6 p.m. local time). These settings are configurable. The ACU also provides an RS-232 serial port, which is connected to the projector to automate the configuration of the projector settings.
Next, when you have your calculations for the amount of amperage per circuit and the number of circuits required, the electrician needs to know where in the room these circuits should be installed. A floor plan and reflected ceiling plan is the most accurate way to specify this. For example, Figure 8-43 shows five dedicated 20A circuits installed along the wall behind the system, with additional receptacles from circuit#5 extended to the ceiling and walls for the WolfVision document camera and Auxiliary LCD displays.
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Figure 8-43 Reflected ceiling plan showing recommended power outlet locations
Finally, remember that one of the primary goals of Cisco TelePresence is ease of use. Therefore, the system is designed to be left on 24 hours a day, 7 days a week so that people can walk in and use it anytime, without trying to figure out how to turn the system on before they can use it. To facilitate this, Cisco has introduced three improvements to reduce the power consumption during off hours:
- In the 1.1 release, the system began automatically putting the plasma displays and projector into standby mode during off hours.
- In the 1.2 release, the system began controlling the WolfVision document camera programmatically to enable us to put it into standby mode during off hours as well.
- In release 1.4, the Auxiliary Control Unit (ACU) was introduced to allow the light façade to be turned on/off automatically, as previously described.
More improvements are likely to be made in the future, so check with Cisco for the latest specifications and power recommendations.
Some customers have asked whether the system can be shut down at night. Doing so will not damage the equipment in any way. The system is designed to be powered off without requiring a soft shutdown. However, it is still not advised because it will reduce the usefulness of the system. Because TelePresence promotes global meetings, it is not uncommon for users to have meetings with colleagues in another country at 10 p.m., or even at 2 a.m.