Application Overview 2-19
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 frequency
! Continue at preset frequency
! Stop
! Fault (EF0)
Three configuration properties are used to select the desired behavior:
! nciRcvHrtBt – Receive Heartbeat
! nciCblLossSpeed – Cable Loss Speed
! nciCblLossFltEna – Cable Loss Fault Enable
The following table summarizes the settings for each type of behavior (X = don’t care): Each behavior is described in additional detail below.
Table 2.22 - Cable Loss Behavior
Behavior nciRcvHrtBt nciCblLossSpeed nciCblLossFltEna
Continue at last frequency 0 X X
Continue at preset frequency Timeout Interval Preset Speed Off
Stop Running Timeout Interval 0 Off
Fault (EF0) Timeout Interval X On
Note: Communication must be established and then lost for these features to function as described
For modes which describe the drive running after a timeout, a run command must have been issued 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
must be added (consult factory).
Upon expiration of the timeout interval, the FAULT LED lights and remains lit until communication is restored.
# Continue Running at Last Frequency
In this mode, nciRcvHrtBt is set to 0, disabling the cable loss feature. The other 2 settings are ignored. If communication is lost, the drive
simply maintains its last commanded state.
# Continue Running at Preset Frequency
In this mode, nciRcvHrtBt is set to the desired interval and nciCblLossSpeed is set to the desired preset speed. If the time between messages
exceeds the timeout interval, the drive’s speed command is set to nciCblLossSpeed and the drive continues running at this new speed.
nciCblLossFltEna must be set to ‘Off’.
# Stop Running
In this mode, nciRcvHrtBt is set to the desired interval and nciCblLossSpeed is set to 0. If the time between messages exceeds the timeout
interval, the drive’s speed command is set to 0 and the run command is set to ‘Off’. nciCblLossFltEna must be set to ‘Off’.
# Fault
In this mode, nciRcvHrtBt is set to the desired interval and nciCblLossFltEna is set to ‘On’. If the time between messages exceeds the timeout
interval, an ‘EF0’ fault is declared and the drive stops. nciCblLossSpeed is ignored.
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