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

How do I communicate with an Omnitronics RTU? 

The serial drivers PCxI, MCxI, COMxI or COMx may be used.

The Ports form should be set up for 19200 baud, 8 data bits, no parity and 1 stop bit.

This drivers does not transmit. It only moniters the receive line to collect data.

I/O Devices form
Name: User supplied unique name
Number: Network wide I/O device number
Address: 1-255 Id of originating RTU
Protocol: OMNI
Port name: Use the "Port name" from the Ports form

Citect.ini option

ReqDelay = 50
Milliseconds Delay between read request, set to 0 to get the fastest screen update time.

Standard citect.ini options

MaxPending = 1, Maximum number of commands that could be handled by the driver at any one time, increase to twice the number of units configured to get maximum update time.
Block = 40 bytes
Retry = 0
Delay = 0
TimeOut = 1000 milliseconds
PollTime = 0
WatchTime = 30 seconds, Data must be received within this time in seconds.


  • OMNI.DLL - The OMNITRONICS driver for windows
  • OMNI.DBF - The OMNITRONICS variable definitions

OMIN Variables

An Analog values (Byte/Int), n is 0 to 98
A0 is Originating RTU id
A1 is status
A2 is number of bytes
A3 is first byte of data
note that when using integer addresses must be either all even or all odd.
Bn Digital value, n is 0 to 783
B9 is aux input state
B10 is aux output state
B17 is first bit of data

Driver Specific Error (decimal)

40 Data is out of date, no data was received within the [OMNI] watchtime (default 30 seconds)