additional, more-complicated example

Author: keenanlang

iocBoot/11-Sequencer/monitor.lua

@@ -0,0 +1,85 @@
+-- monitor.lua
+--
+-- Voltage monitor sequencer -- demonstrates condition functions,
+-- action callbacks, unconditional transitions, event flags, and
+-- the "exit" state.
+--
+-- The monitor watches a voltage PV and sets an alarm PV when the
+-- voltage exceeds a high threshold. The alarm clears when the
+-- voltage drops below a low threshold (hysteresis). The monitor
+-- can be stopped externally via a named event flag.
+
+local seq   = require("seq")
+local db    = require("db")
+local epics = require("epics")
+local event = require("event")
+
+-- Create records
+db.record("ao", P .. "voltage") { VAL = "0", PREC = "2" }
+db.record("bo", P .. "alarm")   { ZNAM = "OK", ONAM = "ALARM" }
+
+-- PV objects
+local voltage = epics.pv(P .. "voltage")
+local alarm   = epics.pv(P .. "alarm")
+
+-- Named event flag for external stop signal
+local stop = event.flag("stopMonitor")
+
+-- Thresholds with hysteresis
+local HI = 8.0
+local LO = 3.0
+
+local prog = seq.program("voltageMonitor")
+
+-- Initial setup: unconditional transition to normal
+prog:state("init", {
+	seq.when() {
+		action = function()
+			alarm.VAL = 0
+			print("Monitor: started (HI=" .. HI .. " LO=" .. LO .. ")")
+		end,
+		next = "normal",
+	},
+})
+
+-- Normal state: watch for voltage exceeding the high threshold
+prog:state("normal", {
+	seq.when(function() return voltage.VAL > HI end) {
+		action = function()
+			alarm.VAL = 1
+			print("Monitor: ALARM (voltage " .. voltage.VAL .. " > " .. HI .. ")")
+		end,
+		next = "alarm",
+	},
+
+	seq.when(function() return stop:test() end) {
+		action = function() print("Monitor: stopped") end,
+		next = "exit",
+	},
+
+	seq.when(seq.delay(0.1)) {
+		next = "normal",
+	},
+})
+
+-- Alarm state: watch for voltage dropping below the low threshold
+prog:state("alarm", {
+	seq.when(function() return voltage.VAL < LO end) {
+		action = function()
+			alarm.VAL = 0
+			print("Monitor: OK (voltage " .. voltage.VAL .. " < " .. LO .. ")")
+		end,
+		next = "normal",
+	},
+
+	seq.when(function() return stop:test() end) {
+		action = function() print("Monitor: stopped") end,
+		next = "exit",
+	},
+
+	seq.when(seq.delay(0.1)) {
+		next = "alarm",
+	},
+})
+
+seq.register(prog)

iocBoot/11-Sequencer/st.lua

@@ -28,5 +28,10 @@ osi = require("osi")
 
 for i = 1, 20 do
 	osi.sleep(1.0)
-	do r = epics.get("lua:red"); y = epics.get("lua:yellow"); g = epics.get("lua:green"); print(string.format("  Red: %d  Yellow: %d  Green: %d", r, y, g)) end
+	do 
+		r = epics.get("lua:red"); 
+		y = epics.get("lua:yellow"); 
+		g = epics.get("lua:green"); 
+		print(string.format("  Red: %d  Yellow: %d  Green: %d", r, y, g)) 
+	end
 end

iocBoot/11-Sequencer/st_monitor.lua

@@ -0,0 +1,69 @@
+-- Sequencer Library Example IOC -- Voltage Monitor
+--
+-- Demonstrates seq library transitions with condition functions,
+-- action callbacks, unconditional transitions, event flags, and
+-- the "exit" state.
+--
+-- Run with: ../../bin/<arch>/testLuaShell st_monitor.lua
+
+dbLoadDatabase("../../dbd/testLuaShell.dbd")
+testLuaShell_registerRecordDeviceDriver(pdbbase)
+
+luaAddModule("../..")
+
+luaLoadFile("monitor.lua", {P="lua:"})
+
+iocInit()
+
+epics = require("epics")
+event = require("event")
+osi = require("osi")
+
+-- Wait for sequencer to start
+osi.sleep(0.5)
+
+--
+--
+-- === Drive voltage above the high threshold (8.0) ===
+-- Expected: Monitor prints "ALARM" and alarm PV changes to 1
+
+epics.put("lua:voltage", 10.0)
+osi.sleep(0.5)
+-- Expected: 1
+epics.get("lua:alarm")
+
+--
+--
+-- === Drive voltage below the low threshold (3.0) ===
+-- Expected: Monitor prints "OK" and alarm PV changes to 0
+
+epics.put("lua:voltage", 1.0)
+osi.sleep(0.5)
+-- Expected: 0
+epics.get("lua:alarm")
+
+--
+--
+-- === Voltage in the hysteresis band (between 3.0 and 8.0) ===
+-- Expected: alarm stays in its current state (0 = OK)
+
+epics.put("lua:voltage", 5.0)
+osi.sleep(0.5)
+-- Expected: 0 (still OK, hasn't crossed HI threshold)
+epics.get("lua:alarm")
+
+--
+--
+-- === Drive above threshold again ===
+
+epics.put("lua:voltage", 9.0)
+osi.sleep(0.5)
+-- Expected: 1
+epics.get("lua:alarm")
+
+--
+--
+-- === Stop the monitor via named event flag ===
+
+event.flag("stopMonitor"):set()
+osi.sleep(0.5)