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Chapter 3 Paramters/Functions Innovation Series Medium Voltage GP Type - G Drives GEH-6385
The LAN watchdog function describes the set of mechanisms the drive uses to
determine the statu s of the connection between DSPX and th e module immediately
“above” the drive in th e LAN hierarchy. For Dual-Port RAM in terfaces, such as that
used for an embedded ACLA con troller and for a direct LAN inter face, the watchdog
takes the for m of a handshake pr otocol. In this han dshake protocol , the drive
determines the presence of a minimum level of intelligence on the host on the LAN
side of the shared memory. For ISBus interfaces, such as that used by a remote or
embedded ACLA controll er, the watchdog reflects the r eception of ISBus frame
synchronization codes. The watchdog function’s immediate authority is limited to
alarms and status variables, although the status information does play a functional
role in the interface man agement. Note that the watchdog does not offer information
about the LAN connection’s status which may be supported beyond the immediate
interface to DSPX. In fact , many device networks offer no m eans of determining
basic network health.
The LAN heartbeat functi on is visible to the user. The heart beat function uses
published signal map channels, and is available for use by the application. It provides
a means to “loop ba ck” a signal bet ween the drive an d any level in the LAN
hierarchy so a higher- level controller can validat e the entire connection pathway,
including the drive it self. Locally, the drive can be con figured to trigger a trip or
alarm if the heartbeat r eference signal fails to tran sition within a configurable per iod
of time. The heartbeat offers the most robust validation options from a system
perspective, alth ough it offers the least informat ion about the detected problem’s
location.
The System ISBus error alarm occur s when an ISBus fault is detected in th e DSPX
control. The var iable Sys ISBus error reg contains the bit- coded value of the last
ISBus fault detected; each bit indicates a particular ISBus fault seen by the control.
The variable Sys ISBus error cnt increments upon fault detection. When initializing
the interface, the user should expect the alarm to signal intermittently.
The Frame PLL not OK alarm occurs when phase-lock bet ween the DSPX control
and the System ISBus or (local ACL) is not assured. Detection of the fault is enabled
when the paramet er Network interface i s configured to select an interface f or which
synchronized operation is supported. This alarm indicates that data coherency is
compromised. Statu s of the Frame Phaselock Loop function can be observed vi a the
signals Frame PLL OK status, FPLL Phase error, and FPLL Freq Output.
LAN Signal Map
The following information describes the primary signal interface between the
Innovation Series Drive and the product application layer interface. The application
layer may consist of an embed ded ACL card, a direct LAN interface ca rd, or an
application-level ISBus serial bus.
The LAN Signal Map is a fixed signal map that defines dedicated registered
communication chann els for specific signals. It i s defined in terms of paired
reference and feedback pa ges that are the same size physical ly. The internal data
organization of the refer ence and feedback pages may differ . The standard
Innovation Series signal ma p page consists of ei ght 32-bit elem ents.