Status And Communication Parameter Areas - Hitachi SV.LINK User Manual

5.4 Status and Communication Parameter Areas

This section details the status areas, which indicate the SV.LINK status, and the communication
parameter areas, which are required for communications with the MELSEC.
As the status and communication parameter areas, BD registers of from BD000 to BD03F are
used. The registers BD000 through BD03F are reserved for SV.LINK although some unused
areas are contained. When SV.LINK is used, do not use the above areas for any other purposes.
Use the same areas (BD000 through BD03F) no matter whether the SV.LINK module is defined
as the main module or submodule.
The SV.LINK module checks for communication parameter rationality the moment the user starts
a communication process. If any communication parameter is in error, the SV.LINK module
does not start communications (the ERR LED glows and the module operation comes to a stop).
(1) Status areas
The status areas store the error codes for errors that are caused during communications and
counts of the number of cyclic communications carried out since a reset/power-on reset.
Register
number
BD000 Error code
BD001 Cyclic communication counter
(count)
BD002 Reserved for future use
BD003 Reserved for future use
BD004 Reserved for future use
BD005 Reserved for future use
BD006 Reserved for future use
BD007 Reserved for future use
(*1) If communication recovery is achieved through retries after the occurrence of a communication
error, the error code area is cleared to zero (0). In such an instance, the previously
encountered errors can be referenced by viewing the error code trace area. For the error code
trace area, see "7.3.3 Communication error codes."
(*2) This counter holds a count of the number of communications that have been carried out since
power ON. It is cleared to zero (0) when a power outage occurs.
Area name Area description
Stores the error codes for errors that
are caused during communications.
While normal communications are
maintained, the value 0 is stored.
For detailed error code descriptions,
see "7.3.3 Communication error
codes."
Holds a count of the number of
communications carried out with the
MELSEC.
5-5
5 PROGRAMMING
Remarks
(*1)
(*2)