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

When I start Citect there is no PLC displayed for 30 seconds. What is causing this to happen? 

When Citect starts up, it will wait for all PLCs to come online before displaying any data, processing alarms, trends or reports. If some PLC cannot be brought online, Citect will timeout after 30 seconds and display the data from the online PLCs. The data from the offline PLCs will be 0. What is happening in this case is that one of the PLCs is offline, or taking a long time to come online. Locate the PLC that is not coming online to fix the problem.

More Detail:

The startup timeout is controlled by the parameter [COM]StartTimeOut=30, where the default is 30 seconds. You can reduce this timeout to force Citect to display data from the valid PLCs quicker. To find the I/O Devices that are offline, check the Hardware Alarm page. You can also see the I/O Devices that are offline at startup in the Citect kernel by setting the parameter [IOServer] InitMsg=1. When the startup timeout occurs, you will see the message 'Communication system timeout' in the kernel. If the InitMsg is set to 1, all the I/O Devices that are offline at this time will be displayed in the kernel as 'Unit <name> offline'. This should allow you to find the units that are causing the startup communication timeout.

See also Q1355