Chapter 4. Ladder Diagram (LD) Programming
GFK-2950C
February 2018
91
4.4
Contacts
A contact is used to monitor the state of a reference address. Whether the contact passes power
flow depends on positive power flow into the contact, the state or status of the reference address
being monitored, and the contact type.
A reference address is ON if its state is 1; it is OFF if its state is 0.
Contact
Display Mnemoni
c
Contact Passes Power to Right...
Continuation
Contact
CONTCON if the preceding continuation coil is set ON
Fault Contact
FAULT
if its associated BOOL or WORD variable has a point fault
High Alarm
Contact
HIALR
if the high alarm bit associated with the analog (WORD) reference is
ON
Low Alarm
Contact
LOALR
if the low alarm bit associated with the analog (WORD) reference is
ON
No Fault
Contact
NOFLT
if its associated BOOL or WORD variable does not have a point fault
Normally Closed
Contact
NCCON
if associated BOOL variable is OFF
Normally Open
Contact
NOCON
if associated BOOL variable is ON
Transition
Contacts
NEGCON (negative transition contact) if BOOL reference transitions from ON
to OFF. Updated every time it is called.
NTCON
(negative transition contact) if BOOL reference transitions from
ON to OFF. Updated once per scan.
POSCON (positive transition contact) if BOOL reference transitions from OFF
to ON. Updated every time it is called.
PTCON
(positive transition contact) if BOOL reference transitions from OFF
to ON. Updated once per scan.
Summary of Contents for PACSystems RSTi-EP
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