Category: Rack

Rittal rack design

The water cooled Rittal racks are composed of two rack units sharing one Liquid Cooling Package LCP . The racks are on the right and on the left side of the LCP unit.

On the back side ( warm air side ), the LCP unit pulls the warm air and pushes it through the heat exchanger to the front side ( cold air side ).

control units

CMC TC unit rack

The two racks are controlled by the so called [ CMC TC control unit | CMC control unit ]. Two of the ports of the control unit are occupied with IO units, one for each rack. The ports of each IO unit are entire used with two relays, one temperature sensor and one door sensor. The relays are used to switch on and off the rack and prevent the rack from overheating.

CMC basic LCP

The CMC control unit in the LCP unit is responsible for recording the temperature of the water in- and outgoing water, the temperatures of in- and outgoing air on three positions and the water flow rate. Additionally a smoke detector is connected with one of the ports. The CMC unit controls the water valve and the fan speed.

manipulating the racks

The racks can be switched on and off by using the CMCctrl perl script which is currently placed in ~loki/hancluster/Racks/Racks_Rittal/Administration on the 130.75.117.102 . CMCctrl -h shows further options. Switching the racks on works with CMCctrl -r 3-9,12,17 -on which switches on the racks 3 to 9, 12 and 17, respectively. CMCctrl -r .... -all monitors the temperature and reports an open door. Furthermore, it monitors the status of the relays. If the first relay is in the off state and the second is in the on state the rack is in the normal state. Unfortunately, it is not sure whether the rack is has power or not since the racks just keeps its current status. Hence, in the case of an antecedent over-temperature, the rack stays off. If the first relay is in the on state, the racks is surly on. If both relays are in the off state the rack is surly off. This state can be achieved by using CMCctrl -r ... -offcourseoff .

status of the LCP

The status of the LCPs can be monitored by using the perl script CMC_Basic_ctrl in ~loki/hancluster/Racks/Rittal_LCP/Administration . The -l options determines the LCP unit, e.g., CMC_Basic_ctrl -l 2-7,9 handles the LCP units from 2 to 7 and 9 respectively. The option -all shows several values as the 3 temperatures of the in- and 3 temperatures of the outgoing air. It shows the amount of heat that is carried away, the flow rate of the water, the valve status and the temperatures of the in- and outgoing water.