Grass Valley VM 3000 System Controllers v.7.4 - Manual (Page 253)

Configurator Switcher Description Table
5−43 VM 3000 Installation and Operating Manual
DM 400 Off Time
DATA SWITCHING − OFF TIME BETWEEN SWITCHES
Number of frames switcher will dwell on Safe input when switching between controlled devices
When a switch occurs from one VTR control cable to another where the VTRs are of different types, the switch can occur
so rapidly that the editing system may not know that a new type of VTR has been connected. This can result in editing
inaccuracies since the editing system may be using ballistics for the wrong type of VTR. See Figure 5−27.
Figure 5−27.
Editor
VTR 1
VTR 2
Data Switcher
“Safe input”
To avoid this problem, the data switcher can be set to switch to a Safe input, wait for a specified minimum number of frames,
and then switch to the new device. This will cause the editing system to send a request to the new VTR to identify itself and
get the correct ballistics.
The wait period is set in the “DM 400 Off Time” column of the Switcher Description table. A setting of approximately 3/4
second is recommended (20 frames). The maximum value is 99 frames.
The delay will only occur when a data switcher is switching real devices, and only when Enforce (see page 5−42) is turned
on.
The DM 400A data switcher requires a two−row entry on the Switcher Description table; in this case the DM 400 Off Time
entry is made on the Reverse switcher row (the row with the letter “R” in the RV column).
For an overview of data switching, see page 2−37.