Applies To:
  • CitectSCADA 1.00 1.01 1.10 1.11 1.20 2.00 2.01 3.00

How do communicate to a TI PLC via the programming port? 

By using the TiDirect protocol. The serial drivers PCxI, MCxI, COMxI or COMx may be used.

Setup the PLC with the appropriate communication parameters i.e. baud rate, 7 data bits, odd parity.

I/O Devices form
Name: User supplied unique name
Number: Network wide I/O device number
Address: Not used
Protocol: TIDIRECT
Port name: Use the "Port name" from the Ports form

Standard citect.ini options

MaxPending = 2
Block = 20 bytes
Retry = 0
Delay = 0
TimeOut = 2000 milliseconds
PollTime = 0
WatchTime = 30 seconds


  • TIDIRECT.DLL - Tiway Direct Driver for windows
  • TIDIRECT.DBF - Tiway Direct variable template

TIWAY Variables

X1 Discrete Input
Y1 Discrete Output
C1 Control
V1 Variable
WX1 Packed Discrete Input
WY1 Packed Discrete Output
TCP1 Timer Counter Preset
TCC1 Timer Counter Current
LKC1 Loop Gain
LTI1 Loop Reset Time (minutes)
LTD1 Loop Rate Time (minutes)
LHA1 Loop High Alarm Limit
LLA1 Loop Low Alarm Limit
LPV1 Loop Process Variable
LPVH1 Loop PV High Limit
LPVL1 Loop PV Low Limit
LODA1 Loop Orange Deviation Alarm Limit
LYDA1 Loop Yellow Deviation Alarm Limit
LTS1 Loop Sample rate (seconds)
LSP1 Loop Setpoint
LMN1 Loop Output (percent)
LERR1 Loop Error
LMX1 Loop Bias
LHHA1 Loop High-High Alarm Limit
LLLA1 Loop Low-Low Alarm Limit
LRCA1 Loop Rate-of-change Alarm Limit / Minute
LSPH1 Loop Setpoint High Limit
LSPL1 Loop Setpoint Low Limit
LADB1 Loop Alarm Deadband
LKD1 Loop Derivative Gain Limiting Coefficient
AHA1 Alarm High Alarm Limit
ALA1 Alarm Low Alarm Limit
APV1 Alarm Process Variable
APVH1 Alarm PV High Limit
APVL1 Alarm PV Low Limit
AODA1 Alarm Orange Deviation Alarm Limit
AYDA1 Alarm Yellow Deviation Alarm Limit
ATS1 Alarm Sample rate (seconds)
ASP1 Alarm Setpoint
AERR1 Alarm Error
AHHA1 Alarm High-High Alarm Limit
ALLA1 Alarm Low-Low Alarm Limit
ARCA1 Alarm Rate-of-change Alarm Limit / Minute
ASPH1 Alarm Setpoint High Limit
ASPL1 Alarm Setpoint Low Limit
AADB1 Alarm Alarm Deadband