Brief Introduction to TWTPM Database Devices Jan. 14, 2000 Updated April 4, 2001 for Download-enable devices Dennis J. Nicklaus All the TWT Devices are entered and active, at least. The Accumulator device names have the form A:xxccnn where xx indicates which "area" it is in, e.g. SP =Stacktail Momemtum, SD=Stacktail Delta, CV=Core Vertical, CH=Core Horizontal, CM=Core Mom. 4-8GHz (AP50), CP = Core Mom 2-4GHz dd is a "channel" name. For each twt, there is a PF, PR, HV, and HM channels. nn is the TWT number, e.g. 01-32 for SP devices, 01-04 for SD, 01 and 21 for CH and CV, 01 and 02 for CM, 01 for CP. PF=Power forward, includes on/off/reset control, dig. status. The reading channel includes the full 16bit reading from the amplifier. That reading includes a few digital status bits (trip & fail comp. & latch) as well as the 8bit analog value. The analog value is in the higher of the 2 bytes and is picked off by the primary transform. There used to also be FP devices. I am obsoleting all the FP devices. These used to give just the analog value of the forward power, and it seems they were only necessary for alarms to work. NOW, you can put an analog alarm on the reading of the PF device. Note that the reading and alarm default data size are length =2. If you do set alarm limits on the PF or PR analog channels, you must remember that you are only setting the top 8 bits of a 16bit quanitity and the value of the lower 8 bits is indeterminate. Here's what happens (after a fix of the reverse transform gets released later today): You enter in an engineering value for the max, e.g. 188. This gets reverse transformed into a Raw value, e.g. hex A600. Because, remember on the readout, the analog reading is only in the upper 8 bits. On the front end computer, this value is compared to the readout, where, the lower 8 bits are just some digital status bits, so they might have value FF (255) or they might have value 00. So if the value of the analog channel was A6, then it might be comparing the readout value A600 to your max limit of A600, or it might compare A6FF to your max limit of A600, triggering the alarm. See me if you are still confused about this For the Debuncher TWTs, the channel names and twt numbers are similar, but the names are of the form: D:tbddnn dd is a "channel" name, the same as above nn is the TWT number as above t is a "typecode". t=H means a Horizontal Band t=V means a Vertical Band t=P means a Momentum Band b is the band number (b = 1, 2, 3 or 4) For example, D:P2TW08 means debuncher momentum band 2, TW channel, TWT number 8. ------------------------------------------------------------------- CPU Status Devices There are also two other devices of interest for each TWTPM. These reflect status of the TWTPM CPU and crate. For the accumulator, these are A:TWTATM A:TWTACP A:TWTACM A:TWTAID A:TWTAUP A:TWTADN A:TWTATM gives the reported VME crate temperature for that CPU. A:TWTACP gives a digital status readout of various conditions that are monitored in the VME crate (e.g. temperatures or voltages high or low) and by the TWTPM software (such as detecting whether TWTPM cards are missing, and whether any TWTPM's 3bit ID header doesn't match with the expected value). A bitmask of which TWTPMs have cards missing is given in the reading field. (each TWTPM CPU can upto 32 TWTPMs and there are 32 bits in the READING value, so if a bit is 1, it indicates that the corresponding TWTPM CPU has detected a TWTPM card missing). Detecting a TWTPM card missing also induces other actions by the TWTPM cpu, such as turning off the connected TWTs. A:TWTACM also gives the 32 bit mask of which TWTPMs have been detected with a card missing by the CPU. In this device, the mask is returned in the digital status property so that extended text and digital alarms (if desired) can be associated with it. Note that the extended text for each bit is the symbolic name of the first TWT on the TWTPM corresponding to that TWTPM (as also shown in runtwt.config). A:TWTAID is similar to A:TWTACM, but it the 32 bit mask of which TWTPMs an invalid 3bit ID header (or have kicker or chiller enables which don't match the values expected for that 3bit ID header). Just like the CardMissing device, this is in the Status property. A:TWTAUP is used to read out the uptime of the CPU. A:TWTADN can be used for the following purposes: Digital Control: Reset causes the front end to download the database alarm blocks and settings again. On turns on alarm reporting from the front-end Off turns off alarm reporting from the front-end The front-end is still doing the alarm-scan (reading the devices), it just will not send any alarm reports if it finds alarm limits exceeded. Digital Status: Gives various status indicator bits about the database download (alarms & seettings). Note that a value of 0403 is normal. Reading: If the "Error Processing Setting" or "Error Processing Alarms" bits indicate errors, then the reading channel can be used to find out how many alarms and settings failed. Each TWTPM cpu has a similar set of devices, named x:TWTyTM x:TWTyCP x:TWTyCM x:TWTyID x:TWTyUP x:TWTyDN where x,y are replaced with: A,A: for accumulator A,C: for accumulator Core Momentum (AP50) D,D: for debuncher bands 1&2 D,E: for debuncher bands 3&4 (2nd debuncher system) R,R: for recycler Z,T: for test stand