JUMO 705010 mTRON T - Multichannel Controller Module Operating Manual - Manual (Page 52)

6 Configuration
52
6.3 "Independent controller" operating mode
The controller module can be configured for independent operation. This enables it to continue
to operate if communication fails between the controller module and the central processing
unit.
 Chapter 6.4 "Device data", page 54
Principle
If the "Independent controller" operating mode is enabled, the controller module can contin-
ue to perform control tasks with the remaining resources if communication fails (all internal
functions continue to run).
Otherwise, if the "Independent controller" operating mode is not enabled, the controller
channels and outputs of the controller module switch off if communication fails.
The controller module detects within 2 seconds whether the conditions for changeover to inde-
pendent mode are present. These include:
•
No connection to the central processing unit via the system bus (failure of all communica-
tion)
• Central processing unit changes to the "Stop" system state (failure of cyclical communica-
tion)
When changing to independent mode, the controller module continues to operate with the most
recent valid setpoint inputs, provided it has been configured accordingly ("Last setpoint value
for independent mode" parameter). This affects the setpoint input both via external signals
(NV_...) and through internal functions or calculations.
A controller module that has been configured for independent mode also operates in indepen-
dent mode during system startup until the "Run" system state is achieved.
Prerequisites
One prerequisite for independent mode is that the actual value of a controller channel is ob-
tained via an analog input of the controller module. Likewise, the output level must be supplied
through an analog or digital output of the controller module to the control path.
If external signals (NV_...) are also used in normal operation, these are no longer available after
changeover to independent operation. The relevant replacement values are used instead. You
can only configure these with the setup program and must adjust them to the relevant applica-
tion with appropriate dimensioning.
 Chapter 6.14.5 "Replacement values (overview)", page 115
Display of operating mode
In addition to the voltage supply, the two-color "P" LED (Power) also indicates the operating
mode of the controller module:
•
Green: Normal operation, communication present with the central processing unit
• Orange: Independent operation, no communication with the central processing unit
The operating mode is also displayed on the multifunction panel.
TIP!
When configuring the controller module, a digital input for switching off the relevant controller
channel is to be included where applicable. This is the only way to ensure that a controller
channel can also be switched off when in independent mode.