Request for TEVCAL to calculate and

write data to MDAT frame 12

The BLM front end desires to read state information from MDAT frame 12 to determine BLM abort thresholds. We propose expanding the TEVCAL OAC to write state information to MDAT using the following outline.

The proper BLM thresholds will depend on many accelerator conditions such as – Tevatron energy, Collider state, and whether Pbars are present in the machine. Also, the status of the abort loop is important to setting the abort thresholds. The OAC will need to constantly be aware of the following parameters:

V:CLDRST

V:TVBEAM

T:IPROG

The OAC will also need to know if event $47 or $48 was the most recently occurring event. The OAC will also set the state device V:TBLMAB to the same value as MDAT12. Also, TEVCAL will own a device T:BLMHFE that can be set from a parameter page. The parameter value will read in GeV and indicate what energy is defined as the transition from low to high energy for the BLMs.

The following definitions will be used to determine the proper value of V:TBLMAB:

Pbars present if (V:CLDRST = 6) or (V:TVBEAM > 3)

Scraping if V:CLDRST = 13

HEP if V:CLDRST = 14

High Energy if T:IPROG > (T:BLMHFE * 4.44)

The High Energy flag can actually only transition when V:CLDRST is equal to 9, 19, 23, or 24. On event $47, MDAT12 (and V:TBLMAB) should freeze until event $48 is detected. At event $48, the data should once again update according to the logic diagram below.

There must be away to override the logic diagram below and manually set the value of V:TBLMA (and MDAT12) via an ACNET setting. When this override condition is in effect, the OAC should post an alarm.

The value of V:TBLMAB will be determined using the following

logic: