Medium Transport; Low Wing; 2 Turbojet Eng
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 12
Workload; Distraction; Situational Awareness; Confusion; Communication Breakdown
ATC Issue All Types; Conflict Airborne Conflict; Deviation / Discrepancy - Procedural Published Material / Policy
Staffing; Weather; Procedure; Human Factors; Airspace Structure; Airport
Broken 047[ceiling] and trying for visuals on west flow. Multiple layers moving in.   27R is diving in at 40; 27L is running the ILS and I'm 28C diving to 40 also trying to get the visual.  A few conversations with the MAC about how I'm really not seeing the field very well at all.   On a side note it's Saturday evening here at C90 and we are always short.  Tonight we are real short.  Down 7 bodies; 19 on the shift to my knowledge and digging up monitors is a real challenge.  They ended up having to pull the MAC off AND the FLM off to open up 2 monitors.  Now we are two extra set of eyes short due specifically to staffing.  That being said in the middle of conversation with my MAC I forgot to tell Aircraft X to join the localizer and blew him right across into the Aircraft Y on 27L.  I tried to take the quickest action I could but I'm not sure there was even a mile between them.  The other situation was the Aircraft Z I  had to pull out because I don't think 27L was on a visual.  I tried to stop Aircraft A at 5000 and called him Aircraft B instead and he correctly didn't respond and I missed it.  Then I had those two at 4000 I don't know how much separation except it was below 3 miles. On nights like this we; myself included; do everything we possibly can to run the visuals.  Even when the pilots and we ourselves are struggling we just keep trying and working at it.  That being said if we cant see it than we cant see it and just need to go out for the ILS.
C90 Controller describes situation where they are trying to vector aircraft for the visual approach but are having trouble with getting aircraft in resulting in separation losses.