Operation For Programless Communications; Timing Of Turning Power On And Off - Omron E5C-T Series Communications Manual

6 Programless Communications
6-1-3

Operation for Programless Communications

Programless communications are performed in the following order of communications unit numbers.
0 (master) → 1 → 2 → ... → Highest communications unit number → 0 → 1...
The master (the Controller with communications unit number 0) starts programless communications
approximately five seconds after the power supply to it is turned ON. (Communications are not per-
formed until the power supply to the master is turned ON.) When the master starts communications, the
slaves (the Controllers with a communications unit number other than 0) also start communications.
After communications have started, they will continue for the remaining E5@C-T Controllers even if one
or more of them (including the master) stop. However, the communications cycle will increase while
waiting for communications from the stopped E5@C-T Controllers.
6-1-4

Timing of Turning Power ON and OFF

 Turning ON Power
Turn ON the power supply to the E5@C-T Controllers either after the PLC or at the same time as the
PLC. The following may occur if the power supply is turned ON to the PLC after programless
communications have started.
• The PLC may detect a communications error.
• The Response Flag may change to eeee once at startup.
 Turning OFF Power to Mitsubishi PLCs
To turn OFF the power supply while communications with the PLC are active, change the E5@C-T
Controller to the initial setting level first, and then turn OFF the power supply. If you turn OFF the
power supply to an E5@C-T Controller during programless communications, the PLC may detect a
communications error.
 Restarting only the E5@C-T Controllers
Use the following procedure to restart the E5@C-T Controllers.
1
Change all of the E5@C-T Controllers to the initial setting level.
2
Cycle the power supply in order to the slaves (the Controllers with a communications
unit number other than 0) and then to the master (the Controller with a communications
unit number of 0), or change the slaves and then the master back to the operation level.
Note: If the above procedure is not followed and the PLC detects an error, clear the error from the program in the
PLC.
6 - 4
E5C-T Digital Temperature Controllers Programmable Type Communications Manual (H186)