ECS Scale

In order to give an idea of the scale of the Experiment Control System we will estimate the number of Control PCs that will be needed to implement the complete control system. The major control areas are: the control of electronics, the control of DCS devices and the control of the Event Filter Farm. We will base this exercise on the type of interface or the type of device connected to the control system.

Table 1 gives the decomposition of Controls PCs associated to the control of CC-PCs per sub-detector. It is assumed that one Controls PC can drive ~50 CC-PCs.

Table 1                       PCs controlling electronics interfaced via Ethernet/CC-PCs

Table 2 gives the number of Controls PCs needed to drive electronics controlled via the SPECS interface. Each SPECS master board has 4 independent channels and can in principle drive up-to 128 slaves. It is assumed that up-to 2 SPECS master cards can be housed in a controls PC.

Table 2                       PCs controlling electronics interfaced via SPECS

Table 3                       PCs controlling electronics interfaced via CAN/ELMB

Table 3 lists the number of Controls PCs needed to drive the CAN buses controlling the ELMB-based interfaces. It is assumed that each CAN master can control up to 32 ELMBs and that 6 CAN masters can be housed in one Controls PC.

Finally Table 4 gives the number of Controls PCs needed to control the Event Filter Farm. The assumption is that one control PC will handle two sub-farms.

Table 4                       PCs controlling the Event Filter Farm

Table 5 summarises the number of Controls PCs needed for the DCS equipment, i.e. the equipment controlling and monitoring the operational state of the LHCb detector and infrastructure.

Table 5                       PCs controlling DCS devices

Table 6 shows a summary of the previous tables in terms of Controls PCs. The total number needed is ~100, where almost 30% are attributed to the control of the Event Filter Farm.

Table 6                       Total number of Controls PCs