Yaskawa GPD505 - Manual (Page 21)

TM4028 7/12/2001
21
4.4 Cable Loss Behavior
This section describes the configurable cable loss feature of the option card. This feature offers a user
maximum flexibility in determining the drive’s response to a loss of communication.
After some interval without receipt of a message, the drive can be configured to respond in one of the
following manners:
• Continue at last speed
• Continue at preset speed
• Stop
• Fault
(EF0)
Three points are used to select the desired type of behavior:
• AO19 – Cable Loss Timeout
• AO20 – Cable Loss Speed
• BO10 – Communication Fault Enable
The following table summarizes the settings for each type of behavior (X = don’t care):
Behavior Cable Loss Timeout
(AO19)
Cable Loss Frequency
(AO20)
Fault Enable
(BO10)
Continue at last speed 0 X X
Continue at preset speed Timeout Interval Preset Speed Off
Stop Running Timeout Interval 0 Off
Fault (EF0) Timeout Interval X On
Each behavior is described in additional detail below.
Notes
1. Communication must first be established and then lost for these features to function as described. If a
drive is powered-up without a cable connected or with the master controller offline, a timeout does not
occur.
2. For modes which describe the drive running after a timeout, a run command must have been issued
(BO1 = ‘On’) prior to loss of communications. For safety purposes, it will not automatically start from a
stopped condition. If a user requires the drive to start automatically, additional external wiring may be
added to accomplish this (consult factory).
3. Upon expiration of the timeout interval, the FAULT LED lights and remains lit until communication is
restored.
4.4.1 Continue Running at Last Speed
In this mode, Cable Loss Timeout (AO19) is set to 0, disabling the cable loss feature. The other 2 settings
(BO10, AO20) are ignored. If communication is lost, the drive simply maintains its last commanded state.
4.4.2 Continue Running at Preset Speed
In this mode, Cable Loss Timeout (AO19) is set to the desired interval and Cable Loss Speed (AO20) is set
to the desired preset speed. If the time between messages exceeds the timeout interval, the drive’s speed
command (AO1) is set to the Cable Loss Speed (AO20) and the drive continues running at this new speed.
Communication Fault Enable (BO10) must be set to ‘Off’.