1# @Language: Markdown
2# @Software: VS Code/MacDown/Typora/Vim
3# @Author  : Di Wang
4# @Email   : [email protected]

See epics examples

当设定一个motor时, 我们需要确定设置已经完成, 再进行下一步操作(比如开启快门). 采集数据, 完成后然后关闭快门. 这中间, motor移动的时间不确定, 采集数据的时间不确定. 而使用轮询的方式又显得不可靠.

安装

1example_DBD += busySupport.dbd
2example_LIBS += busy

用法

首先使用put-callback修改一个record的值, 这个record的FLNK或OUT link指向busy record. 当busy record的值为1时, callback不会返回. 直到busy record的值变为0(通过CA 或者 asyn device support等), callback才会完成.

如果使用CA的话, 使用-c指定asynchronous put, -w指定等待时间, 默认为1秒.

1caput –c –w 20 DemoDevice 5
2caput –c –w 20 DemoDevice 1
3caput –c DemoDevice 5
4caput –c DemoDevice 4

 1# Demo of 'busy' record
 2#
 3# Basic idea:
 4# When writing a "1" to the busy record,
 5# it remains in the active/busy/processing state
 6# until something writes a "0" to it.
 7#
 8# This example simulates a slow device
 9# with a "DemoDevice" setpoint
10# and a "DemoDeviceReadback" readback
11# that slowly follows the setpoint.
12#
13# Writing to the setpoints sets the busy record.
14# Since the DemoDevice has an FLNK & OUT chain
15# to the busy record, performing a "put callback"
16# via channel access will thus hang while
17# the busy record is active.
18record(ai, "DemoDevice")
19{
20    field(DESC, "Setpoint")
21    field(FLNK, "DemoDeviceStart")
22}
23
24record(ao, "DemoDeviceStart")
25{
26    field(DOL, "1")
27    field(OUT, "DemoDeviceBusy PP")
28}
29
30record(busy, "DemoDeviceBusy")
31{
32    field(DESC, "BUSY Record")
33}
34
35# Readback slowly follows the setpoint
36record(calc, "DemoDeviceReadback")
37{
38    field(DESC, "Readback")
39    field(INPA, "DemoDeviceReadback")
40    field(INPB, "DemoDevice")
41    field(CALC, "(A>B)?(A-0.1):((A<B)?(A+0.1):B)")
42    field(SCAN, ".1 second")
43    field(PREC, "2")
44    field(FLNK, "DemoDeviceDone")
45}
46
47# When readback matches the setpoint,
48# busy record is cleared and a pending
49# "put callback" will complete
50record(calcout, "DemoDeviceDone")
51{
52    field(INPA, "DemoDeviceReadback")
53    field(INPB, "DemoDevice")
54    field(CALC, "ABS(A-B)>0.2")
55    field(OOPT, "Transition To Zero")
56    field(OUT,  "DemoDeviceBusy PP")
57}

asyn

busy record有三种device support,

1device(busy,CONSTANT,devBusySoft,"Soft Channel")
2device(busy,CONSTANT,devBusySoftRaw,"Raw Soft Channel")
3device(busy,INST_IO,asynBusyInt32,"asynInt32")

对于asyn device support, 在使用autosave时初始化有一些问题, 详见: https://epics-modules.github.io/busy/busyReleaseNotes.html