Meinberg FDM511 - Manual (Page 15)

15
Short FDM String
The SHORT string is a sequence of 23 ASCII characters containing simply information
about frequency deviation FD and time deviation TD, seperated by a space character.
The string is send out at the beginning of every new REF time second and ends with the
characters Carriage-Return (ASCII code 0Dh) and Line-Feed (ASCII code 0Ah). The
letters displayed in italics are replaced by the calculated values whereas the other
characters are part of the string:
FD:-00.016_TD:+00.378<CR><LF>
The meaning of the several values is described below:
FD:-00.016 The frequency deviation between calculated and nominal frequency,
with sign character (+/-), resolution: 1mHz, maximum: ±09.999Hz
TD:+00.378 The time deviation between REF time and PL time,
with sign character (+/-), resolution: 1ms, maximum: ±99.999s
Time Deviation Preset String
The time deviation TD can be preset to a value between -99.999s and +99.999s. This
can be done in the setup menu "Time Deviation Init" and also via the serial interface
COM0. Sending the following string to the FDM511 causes the module to set the time
deviation and the PL time is recalculated according to this new value:
TD:+05.873<CR><LF>
This serial method can be used to reset the time deviation back to +00.000s. This is also
caused by pulling down the /Reset input (see rear VG-Edge connector pin assignment)
or by a power-up reset.
Note: The described time deviation preset method is available via COM0, only, and not
with COM1! Furthermore, the output string STANDARD or SHORT has to be choosen
for COM0.