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15
Functionality
Updating
ZTEC
®
set PVs have the option of updating upon instrument state coercion. This option
is controlled by the setOutCoerce PV, which is off by default. If setOutCoerce is off
when a set PV is changed, the user should poll the corresponding get PV to verify the
new value. However, if setOutCoerce is set to on, set PVs will update their own value
based on the current instrument state during processing.
For example, with a ZT4611, when setting an invalid input range of 3, the value will be
coerced to 2. In Channel Access you would see:
with setOutCoerce Off/default:
$: caput setInp1Range 3
Old
2
New
3
with setOutCoerce On:
$: caput setInp1Range 3
Old
2
New
2
A
caget getInp1Range 1
will receive the value of 2 in either case.
There are five ways to process or trigger updates on a PV:
Providing a forward link (FLNK) to the PV within another PV will cause the
FLNKed PV to process after the first PV is processed.
Adding the PV to a fanout PV and processing the fanout (directly, from another
fanout, or from a FLNK) will process each PV in the fanout group in order.
Sending
caput ztec:PvName value
through Channel Access (When sending input
PVs through
caput
, any value will work).
Sending
caput ztec:PvName.PROC 1
through Channel Access.
Setting the SCAN field of the PV to an appropriate interval, as discussed in the
EPICS documentation. By default the SCAN field on all PVs is set to “Passive”,
so only the previous update methods are in effect. Scanning is not recommended
for output PVs.
Interfaces
ZTEC
®
LXI instruments are accessible through several interfaces: drivers, GUIs and
EPICS. Only one non-Channel Access (CA) interface, such as the drivers or ZScope
®
,
may access the instrument at a time. However, connections to the EPICS database are
not restricted. MEDM and EDM GUIs use the EPICS database and as such may have
multiple instances. Note all interfaces are independent and may cause undesirable
interactions if used simultaneously. Parameters changed through non-CA interfaces will
not cause PV values to update. If non-CA interfaces have been used, it is
recommended to call
UtilRefresh
.
UtilRefresh
will cause all PVs to update with the
current instrument parameter values. Capturing waveforms through multiple interfaces
