The variable delay line has been setup for practical use. The hardware and basic software are ready.
The delay time is given by [512-1-mod(C1:LSC-BO_1_0_SET, 512)]*(1/16) ns
Giving 511 (LLLL LLLH HHHH HHHH) to C1:LSC-BO_1_0_SET makes the delayline shortest (+0ns).
Giving 0 (LLLL LLLL LLLL LLLL) to C1:LSC-BO_1_0_SET makes the delayline longest (~32ns).
The SR785 was removed from the rack for our access >> Eric
- Three CONTEC DO-32L-PE cards are found in the Yarm digital cabinet. (I brought a card from WB, but will bring it back).
- The card was installed in the C1LSC chassis.
- The models for c1x04 and c1lsc were modified to include the card. Once they are restarted, the card was recognized without problem.
The frame builder also needed to be restarted (Attachment 1&2). The changes were committed to the repository.
- MEDM screen "CDS_BO_STATUS.adl" has been modified to include the bit monitors for the new DO card. (Attachment 3)
Epics values "C1:LSC-BO_1_0_SET" and "C1:LSC-BO_1_1_SET" are hooked up to the DO block.
- The DO board has DB37(F). I made a I/F cable with a DB37(M) crimp connector, DB25 breakout board, and a ribbon cable.
Pin 1 is connected to pin 14 of the DB25 (GND of the delayline circuit).
Pin 2~10 are connected to pin 1~9 of the DB25 (Switch 1~9 of the delayline circuit)
Pin 18 is connected to X01 (external = spare) (Attachment 4)
- [CONFESSION] A bench +15V power supply was prepared to power the transisters of the DO (Attachment 6). The hot side is connected to X01 (not connected to the DB25),
and the cold side is connected to pin 14 of the DB25. Once we find this is a useful setup we need to make a dedicated interface unit to convert DB37
into DB25 (and provide more connectivities).
- A DB25 M-F cable was installed on the cable tray above the LSC racks.
Delay line unit
- The delay line box was mounted on 34H of the LSC analog rack (Attachment 5).
- The side cross connect power supply was not available (to be described later). Therefore we decided to use the same +15V supply as the one for the DO card.
- Checked the functionarity of the local switches using a function generator @30MHz and the front panel switches. The maximum (~32ns) delay was confirmed.
(Just not enough to have 360 deg shift).
- Now the delay line function was tested with the front panel swicth at "ext". We confirmed that the delay time changes with the number given to C1:LSC-BO_1_0_SET.
What we need further
- Implement delay time slider control (511 = 0ns, 0 = 31.94ns). The delay time is given by
[512-1-mod(C1:LSC-BO_1_0_SET, 512)]*(1/16) ns
- Some independent RF issues I found. (Next entry)