PAGE 23 12-5-97 CHAPTER 3: OPERATION
3.5.1
The Assembly object instances are listed below and can also be accessed through the Explicit
Message connection at the appropriate Assembly object attribute 3. However, this is not recommended
since a Poll connection must be active.
Instance
Type
Name
------------------------------------------------------------------------------------------
1
Input
Drive Status
2
Input
Drive Status w/optional parameter
3
Output
Drive Control
4
Output
Drive Control w/1 optional parameter
5
Output
Drive Control w/2 optional parameters
3.6 Loss of Network
3.6.1
When the Option board is in automatic (network control) mode, and network communications
has not yet been established or has been interrupted, the Option board will affect the drive operation
based on the setting in the Loss-of-Network configuration parameter. At power-up, a ten second delay is
provided to allow the network to become active before Loss-of-Network action takes effect. The Loss-of-
Network configuration parameter may be preset to one of three values: 0-Fault, 1-Use_Last_Values and
3-Use_Term_Value.
The following describes the actions on the drive for each of these values.
0 - Fault
When communications are lost, the drive will immediately fault with an ER5 causing the motor to coast to
a stop. When network communications are restored, the ER5 will be automatically reset. However, the
drive will be maintained at ‘stop’ by lockout state. To regain control and release lockout state, a Poll
message must first be sent with the control word FWD and REV bits set to zero. Once lockout mode is
released, the drive will follow the commands of the last Poll message.
The user can take local (terminal) control of the drive when in ER5 by switching to manual and issuing a
reset. (Note that terminal controls must be at stop before a reset can be issued.)
Switching back to automatic with the network inactive will cause an ER5 to occur. Switching back to
automatic with network active will cause control to either follow the last Poll command word or ‘STOP’
depending on lockout state.
1 - Use_Last_Values
When communications are lost, the drive will continue to run using the last received Poll parameters.
When network communications are restored, the drive will immediately follow the commands of the last
Poll message (lockout state is not activated).
Warning: When in this mode, the only way to stop the drive is through local
control. This requires either a switch to manual mode <or> use the STOP button
on the local keypad. It is the user’s responsibility to take the appropriate safety
precautions.
The user can take local (terminal) control of the drive while in this mode by switching to manual. However,
if the mode is switched back to automatic while the network is inactive, the network control word will be
reset before it is made active. That is, if the user switches back to automatic before the network is
restored, the drive will be stopped regardless of the state of the last Poll message.
