User`s guide

Page 20

Controlinc 1746-C (Version 5.21) Network Master Users Guide (2004-11-18)

4.1.5. 1746-C System Operations at Power Up

The 1746-C software boots up on a power up of the 1746-C module. The general sequence is:

1. Illuminate LED1 & LED2 as an indication that the software is initializing itself and the network.

2. Perform basic internal initializations.

3. Perform the initial diagnostic scan of the network and identify all actuators on the network.

4. Finish internal initializations.

5. Turn off LED1 & LED2.

6. Start standard scanning of the network. Initialization is finished. Normal operations

(scanning) have commenced and are allowing PLC communications.

(LED1 toggles ON during the start of this first scan)

Note 1: Remember that the PLC cannot perform any block transfers until after the network master has

finished polling the network for status information and LED2 has been turned off and the

1746-C starts indicating that it is ready for data (after scanning starts).

Note 2: Even though LED1 turns off immediately after the initial scan after power up and then toggles

back on after normal operations start, the user will not normally see this … at the most it

would be a small flicker. Therefore, to the user that is observing the LED behavior after

restart on a system that has actuators communicating, it will appear that …

During the initial scan when the PLC cannot talk to the 1746-C …

LED1 == ON

LED2 == ON.

Immediately after the initial scan when normal operations start (start of 1

normal scan):

LED1 == ON

LED2 == OFF.