Specifications

B&K Components Device Interface Protocol (BKC-DIP) Specification
Version 2.01.00
Updated 01/24/07
Page 37 of 54
.. 7=1 .. Override IR Locked is locked
.. FF=A.. Activate Override Timeout in 1.0 second
So long as Override Active is activated, the system ignores the System Setting parameters Echo
Enabled, Front Locked, and IR Locked. This allows the user to freely change these System
Settings without interfering with current serial communication parameters. When the user is
finished modifying the device settings, the following command deactivates the Override Settings,
and the device reverts to using the corresponding System Settings:
(00, S, O, 0=0;025E) Override Active is deactivated, use System Settings
NOTE: The Override Settings revert to their default parameter values after a “cold boot” (i.e.
power cycle) NOT a “warm boot” (i.e. awakening from “Sleep” state). See product
specific Appendix P for a listing of the default parameter values.
NOTE: If the Override Settings changes the baud rate, the Echo response will be transmitted at
the new overridden baud rate.
Override Timeout
One use for the Override Setting Baud Rate can be to negotiate higher baud rates. The issue that
arises is what to do if the Override Baud Rate is not reliable. The following scenario could occur:
The System is communicating at 9600 Baud.
The Override command is issued (at 9600 Baud) to change the Override Baud Rate to
115200 Baud.
For whatever reason (long cable, noisy environment, etc.) the unit cannot communicate at
115200 Baud, however the unit is now in Override mode at 115200 Baud.
RS-232 communication is now lost with the unit with no remedy.
The answer to the above dilemma is the use of the Override Timeout parameter. The Override
Timeout parameter specifies a timeout period in which, if the Override Timeout is not cleared, the
BKC-DIP device will drop out of Override mode. This provides the means for a software
acknowledge of the new Override state and a means of recovering from Override Baud Rate
communication loss. The following is an example of the use of the Override Timeout feature:
(0, S, O, 0=1,1=8, FF=A; cs16) Activate Override 115200 Baud, 1.0 second timeout
(transmitted at the non-override Baud rate)
(0, S, O, FF=0; cs16) Clear Override Timeout (transmitted at the new
Override Baud Rate of 115200)
If the previous clearing of the Override Timeout was received within 1.0 seconds
At Override Baud Rate:
(0, G, O, 0; cs16) Get Override Active state
(0, R, O, 0=1; cs16) Reply indicates still in override mode
Else Override Timeout occurred because clearing of timeout was not received
At Override Baud Rate:
(0, G, O, 0; cs16) Get Override Active state
No response from unit
At non-Override Baud Rate:
(0, G, O, 0; cs16) Get Override Active state