Media: fiber optic, GLINK
Record Length: variable, depends on the number of reported clusters

19	18	17	16	15	14	13	12	11	10	9	8	7	6	5	4	3	2	1	0
VRB START				Header Length								#Objects
				Header Format			Object Format					Object Length
				Tick								Data Type
				Turn
				FW Minor Version								FW Major Version
				Status Bits
				Cluster Object(s)
				Data Type								Tick
				Vertical Parity
				Pad Frame(s)
VRB END

Field Definitions

note: empty cells will contain zeros

VRB START = "0101"

Header Length = 0x03

#Objects = the number of clusters, range 0-48

Header Format = Header Format, "001"

Object Format = Object format, "00001"

Tick = The accelerator bunch crossing number

Data Type = varies by quadrant: 0x8A = NE; 0x8B = NW; 0x8C = SE; 0x8D = SW

Turn = The accelerator turn (revolution) number

FW Minor Version = 0x00

FW Major Version = varies with the firmware version

Status Bits = Reserved for diagnostic data

Cluster Objects are 32 bits long, which requires two frames in this record.
Bits [31:16] go into the first frame and bits [15:0] go into the second frame. The 32 bits are defined as:

   [31]:    Set to indicate MIP association
   [30:24]: MIP bitmap. If bit 31 is set this field will contain the 7 MIP strips nearest to the cluster center.
   [23:21]: reserved "000"
   [20]:    Orientiation bit: 0 = V, 1 = U
   [19:16]: reserved, "0000"
   [15:8]:  Cluster center strip position, range 1-144
   [7:5]:   Cluster width (7 means a cluster 7 strips wide or wider)
   [4]:     End cap identifier 0 = South, 1 = North
   [3:0]:   Wedge number, range 0-15

Vertical Parity = not supported, 0x0000

Pad Frame(s) = Pad frames are inserted in order to make the total record length a multiple of 8 frames.
This requirement is imposed by the VRB hardware.

VRB END = "1010"

General Information

This record may contain up to 48 cluster objects. U and V cluster lists are each truncated at 24 clusters. The U cluster objects are listed first.

Revision History

2 November 2005: created JTO
4 January 2006: added parity links