YORK YK — VSD - Run signal

The panel prints VSD - Run signal. The manual lists this message among the medium voltage variable speed drive cycling fault messages and among the variable speed compressor drive cycling fault messages. In the drive group the manual applies it to all model drives.

The OptiView Control Center generates redundant run signals for the drive on two separate paths: one goes through the start relay on the I/O board to TB6-24, and the other goes through the serial communications link. When the MVVSD receives either of the two run commands, a 5 s timer starts; the VSD logic board behaves the same way, starting a 5 s timer when either command arrives. If both run commands are not received within 5 s, the MVVSD initiates this shutdown, and on the VSD a shutdown is performed by the VSD logic board with this message displayed.

• The MVVSD or the VSD logic board did not receive both run commands within 5 s of receiving the first one.
• One of the two signals from the OptiView Control Center — the one through TB6-24 or the one through the serial communications link — did not arrive within that window.

• 5 s — the timer that starts when the MVVSD or VSD receives either run command; both run commands must be received within this window or the drive performs a shutdown.

The shutdown is initiated by the MVVSD, or performed by the VSD, when the fault occurs. For the MVVSD the manual states: Messages automatically clear when the fault condition no longer exists; if the chiller was running when the fault occurred, it automatically restarts.