D0 Radiation Monitoring and SMT Safety System

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Current ALARMS and ABORT Levels

CAMAC Module 335, BLM Instantaneous Radiation Rate:

• Alarm 6.37 Rad/sec on any of 8 devices
• Abort 12.6 Rad/sec on any of 8 devices

CAMAC Module 336, BLM Integrated Radiation Dose:

• Alarm 40 Rad/min on any of 8 devices

If you are unfamiliar with the CAMAC modules used in the front end of the BLMs please refer to:

• D0 Silicon Radiation Protection References

• CAMAC 335 Radiation Dose Monitor

• CAMAC 336 Radiation Logger

• CAMAC 337 SVX Protection Permit Sum

These documents will provide the addresses for CAMAC functions necessary to read and modify the Alarm and Abort settings.
 

Reading and Writing the Alarm and Abort Levels

Both reading and writing to CAMAC crates within the ACNET system are available through the D21 page on any ACNET terminal. If you don't know what an ACNET terminal is, stop right now becasue you shouldn't be messing with the BLM alarm or abort levels anyways. A picture of the D21 page is shown below, and the meaning of the tables are given below the screen capture. Make certain that you have enable "Settings" in both the current window and in the Utilities window of the console. Open the Utilities window by double clicking in the ACNET main window, and then click on the Settings where is says "disabled". For the D21 window, you may need to adjust the DIO Settings from the Pgm_Tools menu.




So what do all of these mystical things mean? So the top line is the header of the page and can safely be ignored. The second line contains several things that are of use.

Run Once - click on this to run your CAMAC commands once.

Run repeatedly - click on this to run your CAMAC commands continously until interupted.

Trap - not sure, but I haven't needed to know.

Front End - this needs to be changed to "TEVF" and is modified by clicking on "-" or "+".

The third line is used to recall saved command sets, but I don't know how to use it. Sorry.

The fourth line of the page gives the heading for the CAMAC command set that you want to execute. Here is a deciphering of their meaning:

X - Place an X in this column for the command that follows to be executed.

C - This is the crate address to be accessed. For the D0 BLM crate this is 9D.

N - This is the slot of the card to be accessed. Look at page D20 for crate 9D to see the slot location of the BLM cards.

A - This is the A() listed in the CAMAC commands from the 335, 336, or 337 documentation. Normally listed like F(3) A(5) for example. Here you would place a 5 in the A column.

F - This is the F() listed in the CAMAC commands from the 335, 336, or 337 documentation. Normally listed like F(19) A(6) for example. Here you would place a 19 in the F column.

ARB - Don't know.

NQR - Huh? what's that.

DATA - This is either the result of a read or the value to be written to the CAMAC card.

STATUS - Okay, if you can't figure this one out, I'm just gonna give up.

EXTENDED STATUS - Don't know. Maybe it's Martian or something.

The above screen shot shows an example of first reading and then writing the CAMAC 336 card in slot 10 of the D0 BLM crate. The first two commands, F(26)A(5) and F(26)A(6), reset the pointers to the ALARM level addresses. The CAMAC command F(3)A(6) reads the ALARM limit level for channel 0, but since each read only gets 16 bits of data, the read must be repeated to get the full 32 bits of data. The LSBs are returned first, and then the MSBs are returned with the second read. So, in this example, the value of the limit is 0x0089A880. (I'll get to translating that into real units in a little bit.)

The writing of a new ALARM level is done by using the F(19)A(6) and F(19)A(7) commands for Channel 0 and 1 respectively. Again, because the limit is a 32-bit word, but the write only takes 16 bits at a time, you must repeat the write command. You must fill in the DATA column next to the write commands, otherwise 0s will be sent to the register and the ALARM set to 0 Rads/min.

Converting CAMAC DATA words into real units

So we now know how to read the words that are set as the ALARM and ABORT levels in the CAMAC cards, but how to convert between these hex values and real units? This is accomplished using the D80 ACNET page. A screen capture of this page is shown below.

Clicking on the "Pgm_Tools" menu, select the DB_Queries option. Within the DB_Queries menu, select the "Crate to Device" menu. Then clicking on "Node", select "TEVF" and then click on crate "9D" for the D0 BLM crate. Then click on "Device Name" and choice one of the 335, 336, or 337 devices. In the picture above the CAMAC 336 module C:D0BRDB is chosen. Finally, click on the "Test Scaling" (this is shown on the capture) and enter either the Raw Data you want converted, or the Common unit that you and I understand. For this module, this is Rads. Therefore the data corresponding to a threshold of 40 Rads/min that should be written to the CAMAC 336 is 0x0122A4C3. If any or all of this is confusing, please send me an email.