The Decarad system was developed at JLab - it consists of 10 GM tubes that connect (signal & HV cables) to a central box. That box has a board inside for changing the HV level and reading out the GM tube signals. It's connected to the outside world with DB9 connector. On the other end of that cable is an RJ50 that plugs into a digi which is then connected to the outside world via ethernet. The software uses the epics tool Stream with an asyn connection to the digi to send commands to read and write. The software is part of the RadiationMonitoring slac epics package.
| PV Name | Purpose |
|---|---|
| $(P):FIRM | read firmware number |
| $(P):HRTBT | heartbeat |
| $(P):HVSTAT | status of high voltage |
| $(P):TEMP | temperature of chassis |
| $(P):HVMON | high voltage reading (V) |
| $(P):HVSETPT | high voltage setting (V) |
| $(P):RACK:Position | String to hold a description of the rack position |
| $(P):nn:DoseRate | readback of dose from GM tube nn (01-10) in mR/hr (close enough, it saturates at xxx) |
| $(P):nn:Position | string to hold a description of the position of GM tube number nn |
| $(P):SEQ | sequence to readout the PVs at 1 Hz. The SEQ record has a delay of 0.06 seconds between sending 1 to each PV's PROC field so commands don't collide in the cable |
There are two sets of decarads (10 heads + central unit) so the PVs listed above are doubled and differentiated by $(P).
Notes on cable connection (from email 8/12/21)
RJ50 cable/breakout (digiport server side) DecaRad Chassis DB9
Pins Pins
1 blue/wht TX- 2
2 org/wht RX- 8
3 org NC
4 green/wht NC
5 green TX+ 7
6 brown/wht RX+ 3
7 brown SGND 6
8 blk/wht NC
9 black NC
10 blue NC
Using Decarad frame.pdf as the basic design
| Thing | source | Qty for 2 frames | total |
|---|---|---|---|
Files from Bob and JLab folks (2020, 2021)
Com Cable Pinout.pdf
Deca_stuff.tar.gzDecaRad_src.tar.gzdecarad_to_the_world.pdf
decarad_to_the_world.pptx
DecRad System.docxiocnl22rfcry.tar.gzLND 714_DecaRad tube_datasheet.pdfSchematic.pdf
80-20.xlsx80-20 Shopping Cart.pdfdecaraddocs.docxLND 714_DecaRad tube_datasheet.pdfDecRad System.docxDecarad frame.pdfdecarad_to_the_world.pdfhow long cables.pptx