LON-bus and serial communication
General note
The control program has some standardized variables of type “SNVT” which permit the
communication with external units via LON-bus. There are input and output values. The input
values permit settings for the controller, which are directly available for the control process. The
output values indicate measuring values and status information of the unit.
Automatic update of variables
At each adjustment of the values in the controller the corresponding output variables are updated.
If there are no condition changes the values will be updated every “nciMaxSendTime” seconds. If
“nciMaxSendTime” is less than 1.0 sec. the values are no more updated in intervals but only if
there is any change.
Adjustments of the input variables will be applied to the controller immediately and cause an
EEProm write access. Keep in mind the limited amount of save cycles.
Definition of the interface variables
Object "Differenzregler"
Name of variable
Type
Input/Output
Values
Resolution
nviSetDiffTemp
SNVT_temp_p
Input
–273.17...327.66 °C
0.01 °C
nviStandbyMode
SNVT_lev_disc
Input
0...255
-----
nvoActualTemp1
SNVT_temp_p
Output
–273.17...327.66 °C
0.01 °C
nvoActualTemp2
SNVT_temp_p
Output
–273.17...327.66 °C
0.01 °C
nvoActualSetPt
SNVT_temp_p
Output
–273.17...327.66 °C
0.01 °C
nvoRelayState
SNVT_state
Output
On/Off for K1...K3
-----
Object "0"
Name of variable
Type
Input/Output
nvoStatus
SNVT_obj_status
Output
object status, see SNVT-list
nciNetConfig
SNVT_config_src
Input
configuration, see SNVT-list
nviRequest
SNVT_obj_request Input
object request, see SNVT-list
Connection information
Simultaneously pressing all keys sends a „Service-Pin“ message (the program version of the
software is indicated in the display.
The controller responds to a “wave” command with a display flashing 3 times.
Note that if a data logger is used the node number may be changed at connection (the domain
must remain “0”). After a controller reset the new address can be queried with parameter “L0” and
“L1”. These parameters may not be changed after connection (ensured by “nciNetConfig“).
Содержание ST48-WHDVM.04
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