Owner's manual

Equipment-to-Host Messages 3-19
3.4 Data Collection
Note the three types of variables: Status Variable (SV), Data Variable (DV), and Equipment Constants
(EC). The Host sets only ECs. DVs are time stamped by being associated with Collection Events IDs
(CEID), and will be reported by FmNT in Event Reports.
3.4.1 Variables
The Equipment has a fixed set of Variables which can be read by the Host. Each variable is identified by
a unique Variable ID (VID). Appendix A lists all variables for both FmNT and standard GEM operations.
There are three types of variables: Status Variables, Data Variables, and Equipment Constants. The Host
can read variables of any type, but can set values only for equipment constants. The Host can read values
for Status variables and equipment constants whenever the Equipment is on-line, but values for Data
Variables are typically meaningful only immediately after certain Collection Events (CEIDs), and so are
typically reported only in Event Reports (S6F11).
3.4.2 Are You There
The Host can send S1F1 at any time to determine if the SECS link is operational. The Equipment
responds with S1F2, if the Equipment is in the ONLINE & COMMUNICATING states. This indicates
Model Number (MDLN) and Software Revision Number (SOFTREV).
3.4.3 Host Requests Status
The Host can send S1F3 when the Equipment is on-line to read equipment constants.
The Host can send S2F13 when the Equipment is on-line to read equipment constants.
For this Equipment, S1F3 and S2F13 with a list of VIDs are essentially the same. That is, either message
can return Variables of any type. However, S1F3 with a zero-length list will return only VIDs of type SV,
and S2F13 with a zero-length list will return only VIDs of type EC.
3.4.4 Setting Equipment Constants
The Operator can change the value for equipment constants. Once the Operator has changed an EC value,
the Equipment will note the EqConstChange event. The VID for the changed EC will be reported to the
Host in the variable ECIDCHANGE.
3.4.5 Event Reports
The Equipment has a fixed set of Events which can occur. Each Event is identified by a unique Collection
Event ID (CEID). The CEIDs are listed in Appendix B.
When an event occurs, the Equipment sends the appropriate S6F11 Event Report message to the Host (if
that particular event has been enabled). Event Reports are defined by the Host (S2F33) and linked to a
specific CEID (S2F35).