MX2020 DC Power Supply Module (-48 V) Description

The MX2020 supports a two zone DC power system. Each zone (upper and lower) is provided power by one half of the power subsystem. In the DC power configuration, the router contains up to eighteen DC PSMs located at the rear of the chassis in slots PSM0 through PSM8 (bottom), and slots PSM9 through PSM17 (top) (left to right). The DC PSMs in slots PSM0 through PSM8 provide power to the lower half of the router components, MPCs in slot 0 through 9, CB-REs in slot 0 and 1, SFBs in slot 0 through 7, and Fan Trays 0, 1, and 2. The DC PSMs in slots PSM9 through PSM17 provide power to the upper half of the router components, MPCs in slot 10 through 19, CB_REs in slot 0, and 1, SFBs in slot 0 through 7, and Fan Trays 0, 2, and 3.

Note:

The MX2020 systems configured for DC input power must use only DC PDMs and DC PSMs. AC and DC PSMs or PDMs must not be mixed within a single system.

Up to nine PSMs may be connected in parallel to increase available system power across MPCs as needed and provide redundancy. Figure 1) shows the DC PSM.

Figure 1: DC (-48 V) Power Supply Module

The DC power subsystem is feed redundant. Each DC PSM can be connected to two separate feeds from different sources that are used to provide feed redundancy. If two feeds are connected, PSM input power will be drawn from the feed with the higher voltage present. There are two PDMs per power subsystem capable of carrying nine feeds each. Connect feeds from one source to one PDM and feeds from the other source to the second PDM of the power subsystem. The primary input of the PSM is a dual redundant feed, INP0 and INP1. Both feeds are active during operation, but both feeds may or may not be providing current. Move the input mode DIP switch to the on or off position to determine the power supply feeds (see Table 1 and Figure 2). In addition, a PSM failure triggers the alarm LED on the craft interface. Each PDM has an LED per feed indicating whether the feed is active or not, or whether the feed is connected properly, see MX2000 Router DC (-48 V) Power Subsystem Electrical Specifications.

Table 1: DIP Switch Positions on the DC (-48 V) PSM
Left Switch Position	Right Switch Position	Input Source
Off	Off	None
On	Off	Input 0 (INP0)
Off	On	Input 1 (INP1)
On	On	Both Input 0 and Input 1

Figure 2: Selecting Input Feed on the (-48 V) DC Power Supply Module

MX2020 DC Power Supply Module (-48 V) Description

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