//INTEGRAS/ELS/PAGINATION/ELSEVIER UK/PLC/3B2/FINALS-7-6-04/0750656794-CH003.3D – 31 – [24–39/16] 19.6.2004
9:07PM
(b) Where the first contact on each rung is a normally closed contact, then the
equivalent instruction wi ll always be:
LDI (Load inverse).
2. Contacts in series
Where there are more than one contact connected in series, then to obtain an output,
all of the contacts must be correctly operated.
i.e. X0 ON.
T1 OFF.
Hence, for the timer coil T0 to be energised, input X0 is operate d AND the input T1
is not operated. This is writt en in an instruction program as:
LD X0.
ANI T0.
Hence, after the first contact on each rung, any additional series-connected contacts
will be preceded by the following:
AND for all normally open contacts.
ANI for all normally ...