HAB Access

Today we updated ourselves on the following information. Access 95 and 97 are supported. HABAccess can write to databases of either format and will create databases that can be opened by either version. (HC83). It is native 32 bit Windows application (HC43) because HABDDE is now a native 32 bit Windows application. As a result of porting to 32 bit, the limitation of 64K of data for each DDE link has been eliminated. (HC43)

If connection to the first host fails, HABDDE attempts to connect to the second host before delaying. (HC82)
HABDDE provides a method for an application to query for the name of the connected host. Specifying a DDE link with a topic of “HABDDE” and an item of “HOST” returns the name of the connected host, or a null string if not connected. (HC140)

Two nodes or addresses can be specified for each host to support dual-redundant TCP/IP networks. The potential drawback is that if the link to the Sampler is not established, no data is written to Access. In the previous version, rows were inserted indicating that no data was available Items linked to multiple records can be hot-linked. (HC41). HABAccess options are saved between executions of HABAccess. (HC35) HABAccess can optionally update rows in an Access table instead of inserting new rows each sample. The update feature requires identifying which items are the key for the table by setting the key column attribute when creating or editing items (HC16).

The alias database is no longer specified via an ODBC data source definition. The location and name of the alias database can be specified via the HABAccess menu under Options. Changing the alias database location also changes the location that HABDDE uses. HABAccess now connects directly to the Sampler to retrieve HABITAT data rather than using HABDDE. The host configuration information can be changed via either HABAccess or HABDDE.

This provides better accuracy and reliability than the previous version and allows the start time to control exactly when the sample is performed. For example, if a sample rate of 1 hour is specified with no start time, the sample will be performed at the top of the hour based on the EMS time. If a start time of “01-JAN-1979 00:10:00” is specified, then the sampling will be performed at exactly ten minutes past the hour each hour.

When HABAccess periodically records data, the time that the data is sampled is now determined by the Sampler based on the clock on the EMS system. The sample periods 24 hours are supported (HC96).