You can subscribe to one of the currency RIC's to get real time data. Use one of the EMA example or tutorial. For example, spot rate for Canadian dollar is CAD=, Pound Sterling is GBP=. The Euro/Sterling FX Cross Rate is EURGBP=. Use RIC search tool to find out the identifier for the currency of interest.

Running consumer - Host: localhost:14002, Service: ELEKTRON_AD, User: user1, RIC: GBP=

Item Name: GBP=
Service Name: ELEKTRON_AD
Item State: Open / Ok / None / 'All is well'
PROD_PERM(1): 213
RDNDISPLAY(2): 153
DSPLY_NAME(3): BARCLAYS     LON
TIMACT(5): 15:40:00:000:000:000
NETCHNG_1(11): 3.0E-4
HIGH_1(12): 1.3259
LOW_1(13): 1.3171
CURRENCY(15): 840
ACTIV_DATE(17): 17 NOV 2017
OPEN_PRC(19): 1.3193
HST_CLOSE(21): 1.3193
BID(22): 1.3196
BID_1(23): 1.3194
BID_2(24): 1.3195
ASK(25): 1.32
ASK_1(26): 1.32
ASK_2(27): 1.32
ACVOL_1(32): 101728.0
...