FB_DALIV2Ramp

Ramp implementation

Basically, the function block is designed such that it issues the required number of OnAndStepUp or StepDownAndOff commands at uniform intervals within the specified ramp time.
The processing of these step and query commands, however, takes time. The further the ramp time is reduced, the more likely it is that the internally calculated time for a StepUp or StepDown command is no longer sufficient; the actual ramp time becomes longer and longer compared to the set time.
In order to be able to realize small ramps, the function of the function block is switched from step mode to DirectArcPower mode below an internally preset limit value of 11 s ramp time. The DALI command DirectArcPowerControl brings the corresponding lamps from their current value to the set end value within the FADE TIME. There are a total of 16 different fade time values, which are stored in the control device of each lamp and can assume the following values:

The next value for the ramp that is set at the function block is taken from the table and programmed for all control gears to be controlled. At 6 s, step 7 = 5.657 s would apply, for example. The same value would also be used for a ramp time of 5 s. Precise timing would then no longer be possible. After successful completion of the ramp control, the value that the master device had before the time setting is transferred back to all control gears.
During the ramp, the output value nActualLevelMasterDev is output as an internally calculated value so as not to burden the DALI bus with constant query commands. This calculation is based on the difference between start and end value and the selected ramp time. Since it is a calculated value, it can be subject to errors caused by rounding and command delays and should only be used as a guide. After completion of the ramp the brightness is queried directly and the output value is exact again.

Comment on the nMasterDevAddr parameter

The DALI system provides facilities not just for controlling lamps individually, but also for addressing them as groups or through common commands. Since the individual devices may belong to different groups, the individual lamps may have different brightness states before a group or common control command. So that it is nevertheless possible to be clear whether the lamps now are to be switched on or off, a master device is assigned to each group, whose state is followed by the other devices. It is not necessary to specify a master device if the function block is to be used to control a single lamp, eAddrType = eAddrTypeShort. In this case, the nMasterDevAddr parameter has no significance.

Inputs

VAR_INPUT
  bEnable                    : BOOL := TRUE;
  bOn                        : BOOL;
  bOff                       : BOOL;
  bToggle                    : BOOL;
  bStart                     : BOOL;
  nEndLevel                  : BYTE;
  tRampTime                  : TIME := t#8s;
  nOptions                   : DWORD := 0;
  nAddr                      : BYTE := 0;
  eAddrType                  : E_DALIV2AddrType := eDALIV2AddrTypeShort;
  nMasterDevAddr             : BYTE := 0;
  tCycleActualLevelMasterDev : TIME := t#0s;
END_VAR

Inputs/outputs

VAR_IN_OUT
  stCommandBuffer : ST_DALIV2CommandBuffer;
END_VAR

Outputs

VAR_OUTPUT
  nActualLevelMasterDev : BYTE;
  bBusy                 : BOOL;
  bError                : BOOL;
  nErrorId              : UDINT;
END_VAR

Requirements