diff --git a/scada-common/constants.lua b/scada-common/constants.lua
index 7c661ee..eaf6dd3 100644
--- a/scada-common/constants.lua
+++ b/scada-common/constants.lua
@@ -2,10 +2,12 @@
 -- System and Safety Constants
 --
 
+---@class scada_constants
 local constants = {}
 
 --#region Reactor Protection System (on the PLC) Limits
 
+---@class _rps_constants
 local rps = {}
 
 rps.MAX_DAMAGE_PERCENT      = 90    -- damage >= 90%
@@ -21,6 +23,7 @@ constants.RPS_LIMITS = rps
 
 --#region Annunciator Limits
 
+---@class _annunciator_constants
 local annunc = {}
 
 annunc.RCSFlowLow_H2O     = -3.2    -- flow < -3.2 mB/s
@@ -44,6 +47,7 @@ constants.ANNUNCIATOR_LIMITS = annunc
 
 --#region Supervisor Alarm Limits
 
+---@class _alarm_constants
 local alarms = {}
 
 -- unit alarms
diff --git a/scada-common/crash.lua b/scada-common/crash.lua
index 45a3874..1942a8d 100644
--- a/scada-common/crash.lua
+++ b/scada-common/crash.lua
@@ -6,8 +6,10 @@ local comms = require("scada-common.comms")
 local log   = require("scada-common.log")
 local util  = require("scada-common.util")
 
-local core  = require("graphics.core")
+local has_graphics, core   = pcall(require, "graphics.core")
+local has_lockbox, lockbox = pcall(require, "lockbox")
 
+---@class crash_handler
 local crash = {}
 
 local app = "unknown"
@@ -34,7 +36,8 @@ function crash.handler(error)
     log.info(util.c("APPLICATION:      ", app))
     log.info(util.c("FIRMWARE VERSION: ", ver))
     log.info(util.c("COMMS VERSION:    ", comms.version))
-    log.info(util.c("GRAPHICS VERSION: ", core.version))
+    if has_graphics then log.info(util.c("GRAPHICS VERSION: ", core.version))    end
+    if has_lockbox  then log.info(util.c("LOCKBOX VERSION:  ", lockbox.version)) end
     log.info("----------------------------------")
     log.info(debug.traceback("--- begin debug trace ---", 1))
     log.info("--- end debug trace ---")
diff --git a/scada-common/log.lua b/scada-common/log.lua
index 51b5373..2c266bb 100644
--- a/scada-common/log.lua
+++ b/scada-common/log.lua
@@ -4,14 +4,11 @@
 
 local util = require("scada-common.util")
 
----@class log
+---@class logger
 local log = {}
 
 ---@alias MODE integer
-local MODE = {
-    APPEND = 0,
-    NEW = 1
-}
+local MODE = { APPEND = 0, NEW = 1 }
 
 log.MODE = MODE
 
diff --git a/scada-common/mqueue.lua b/scada-common/mqueue.lua
index b48e4ad..fc60a1e 100644
--- a/scada-common/mqueue.lua
+++ b/scada-common/mqueue.lua
@@ -4,6 +4,14 @@
 
 local mqueue = {}
 
+---@class queue_item
+---@field qtype MQ_TYPE
+---@field message any
+
+---@class queue_data
+---@field key any
+---@field val any
+
 ---@enum MQ_TYPE
 local TYPE = {
     COMMAND = 0,
@@ -13,22 +21,14 @@ local TYPE = {
 
 mqueue.TYPE = TYPE
 
+local insert = table.insert
+local remove = table.remove
+
 -- create a new message queue
 ---@nodiscard
 function mqueue.new()
     local queue = {}
 
-    local insert = table.insert
-    local remove = table.remove
-
-    ---@class queue_item
-    ---@field qtype MQ_TYPE
-    ---@field message any
-
-    ---@class queue_data
-    ---@field key any
-    ---@field val any
-
     ---@class mqueue
     local public = {}
 
@@ -48,28 +48,20 @@ function mqueue.new()
     -- push a new item onto the queue
     ---@param qtype MQ_TYPE
     ---@param message any
-    local function _push(qtype, message)
-        insert(queue, { qtype = qtype, message = message })
-    end
+    local function _push(qtype, message) insert(queue, { qtype = qtype, message = message }) end
 
     -- push a command onto the queue
     ---@param message any
-    function public.push_command(message)
-        _push(TYPE.COMMAND, message)
-    end
+    function public.push_command(message) _push(TYPE.COMMAND, message) end
 
     -- push data onto the queue
     ---@param key any
     ---@param value any
-    function public.push_data(key, value)
-        _push(TYPE.DATA, { key = key, val = value })
-    end
+    function public.push_data(key, value) _push(TYPE.DATA, { key = key, val = value }) end
 
     -- push a packet onto the queue
     ---@param packet packet|frame
-    function public.push_packet(packet)
-        _push(TYPE.PACKET, packet)
-    end
+    function public.push_packet(packet) _push(TYPE.PACKET, packet) end
 
     -- get an item off the queue
     ---@nodiscard
@@ -77,9 +69,7 @@ function mqueue.new()
     function public.pop()
         if #queue > 0 then
             return remove(queue, 1)
-        else
-            return nil
-        end
+        else return nil end
     end
 
     return public
diff --git a/scada-common/network.lua b/scada-common/network.lua
index f8275bc..d9fa83f 100644
--- a/scada-common/network.lua
+++ b/scada-common/network.lua
@@ -2,19 +2,21 @@
 -- Network Communications
 --
 
+local comms  = require("scada-common.comms")
+local log    = require("scada-common.log")
+local util   = require("scada-common.util")
+
 local md5    = require("lockbox.digest.md5")
 local sha256 = require("lockbox.digest.sha2_256")
 local pbkdf2 = require("lockbox.kdf.pbkdf2")
 local hmac   = require("lockbox.mac.hmac")
 local stream = require("lockbox.util.stream")
 local array  = require("lockbox.util.array")
-local comms  = require("scada-common.comms")
-
-local log    = require("scada-common.log")
-local util   = require("scada-common.util")
 
+---@class scada_net_interface
 local network = {}
 
+-- cryptography engine
 local c_eng = {
     key = nil,
     hmac = nil
diff --git a/scada-common/ppm.lua b/scada-common/ppm.lua
index 90f0b17..6af4e2f 100644
--- a/scada-common/ppm.lua
+++ b/scada-common/ppm.lua
@@ -8,15 +8,13 @@ local util = require("scada-common.util")
 ---@class ppm
 local ppm = {}
 
-local ACCESS_FAULT = nil    ---@type nil
-
-local UNDEFINED_FIELD = "undefined field"
-
+local ACCESS_FAULT        = nil                 ---@type nil
+local UNDEFINED_FIELD     = "undefined field"
 local VIRTUAL_DEVICE_TYPE = "ppm_vdev"
 
-ppm.ACCESS_FAULT = ACCESS_FAULT
-ppm.UNDEFINED_FIELD = UNDEFINED_FIELD
-ppm.VIRTUAL_DEVICE_TYPE = VIRTUAL_DEVICE_TYPE
+ppm.ACCESS_FAULT          = ACCESS_FAULT
+ppm.UNDEFINED_FIELD       = UNDEFINED_FIELD
+ppm.VIRTUAL_DEVICE_TYPE   = VIRTUAL_DEVICE_TYPE
 
 ----------------------------
 -- PRIVATE DATA/FUNCTIONS --
@@ -34,9 +32,9 @@ local ppm_sys = {
     mute = false
 }
 
--- wrap peripheral calls with lua protected call as we don't want a disconnect to crash a program<br>
--- also provides peripheral-specific fault checks (auto-clear fault defaults to true)<br>
--- assumes iface is a valid peripheral
+-- Wrap peripheral calls with lua protected call as we don't want a disconnect to crash a program.
+-- Additionally provides peripheral-specific fault checks (auto-clear fault defaults to true).<br>
+-- Note: assumes iface is a valid peripheral.
 ---@param iface string CC peripheral interface
 local function peri_init(iface)
     local self = {
@@ -307,16 +305,12 @@ end
 -- list all available peripherals
 ---@nodiscard
 ---@return table names
-function ppm.list_avail()
-    return peripheral.getNames()
-end
+function ppm.list_avail() return peripheral.getNames() end
 
 -- list mounted peripherals
 ---@nodiscard
 ---@return table mounts
-function ppm.list_mounts()
-    return ppm_sys.mounts
-end
+function ppm.list_mounts() return ppm_sys.mounts end
 
 -- get a mounted peripheral side/interface by device table
 ---@nodiscard
@@ -390,9 +384,7 @@ end
 -- get the fission reactor (if multiple, returns the first)
 ---@nodiscard
 ---@return table|nil reactor function table
-function ppm.get_fission_reactor()
-    return ppm.get_device("fissionReactorLogicAdapter")
-end
+function ppm.get_fission_reactor() return ppm.get_device("fissionReactorLogicAdapter") end
 
 -- get the wireless modem (if multiple, returns the first)<br>
 -- if this is in a CraftOS emulated environment, wired modems will be used instead
@@ -419,9 +411,7 @@ function ppm.get_monitor_list()
     local list = {}
 
     for iface, device in pairs(ppm_sys.mounts) do
-        if device.type == "monitor" then
-            list[iface] = device
-        end
+        if device.type == "monitor" then list[iface] = device end
     end
 
     return list
diff --git a/scada-common/psil.lua b/scada-common/psil.lua
index 13dcaa5..09686bf 100644
--- a/scada-common/psil.lua
+++ b/scada-common/psil.lua
@@ -9,14 +9,12 @@ local psil = {}
 -- instantiate a new PSI layer
 ---@nodiscard
 function psil.create()
-    local self = {
-        ic = {}
-    }
+    local ic = {}
 
     -- allocate a new interconnect field
     ---@key string data key
     local function alloc(key)
-        self.ic[key] = { subscribers = {}, value = nil }
+        ic[key] = { subscribers = {}, value = nil }
     end
 
     ---@class psil
@@ -28,22 +26,22 @@ function psil.create()
     ---@param func function function to call on change
     function public.subscribe(key, func)
         -- allocate new key if not found or notify if value is found
-        if self.ic[key] == nil then
+        if ic[key] == nil then
             alloc(key)
-        elseif self.ic[key].value ~= nil then
-            func(self.ic[key].value)
+        elseif ic[key].value ~= nil then
+            func(ic[key].value)
         end
 
         -- subscribe to key
-        table.insert(self.ic[key].subscribers, { notify = func })
+        table.insert(ic[key].subscribers, { notify = func })
     end
 
     -- unsubscribe a function from a given key
     ---@param key string data key
     ---@param func function function to unsubscribe
     function public.unsubscribe(key, func)
-        if self.ic[key] ~= nil then
-            util.filter_table(self.ic[key].subscribers, function (s) return s.notify ~= func end)
+        if ic[key] ~= nil then
+            util.filter_table(ic[key].subscribers, function (s) return s.notify ~= func end)
         end
     end
 
@@ -51,32 +49,32 @@ function psil.create()
     ---@param key string data key
     ---@param value any data value
     function public.publish(key, value)
-        if self.ic[key] == nil then alloc(key) end
+        if ic[key] == nil then alloc(key) end
 
-        if self.ic[key].value ~= value then
-            for i = 1, #self.ic[key].subscribers do
-                self.ic[key].subscribers[i].notify(value)
+        if ic[key].value ~= value then
+            for i = 1, #ic[key].subscribers do
+                ic[key].subscribers[i].notify(value)
             end
         end
 
-        self.ic[key].value = value
+        ic[key].value = value
     end
 
     -- publish a toggled boolean value to a given key, passing it to all subscribers if it has changed<br>
     -- this is intended to be used to toggle boolean indicators such as heartbeats without extra state variables
     ---@param key string data key
     function public.toggle(key)
-        if self.ic[key] == nil then alloc(key) end
+        if ic[key] == nil then alloc(key) end
 
-        self.ic[key].value = self.ic[key].value == false
+        ic[key].value = ic[key].value == false
 
-        for i = 1, #self.ic[key].subscribers do
-            self.ic[key].subscribers[i].notify(self.ic[key].value)
+        for i = 1, #ic[key].subscribers do
+            ic[key].subscribers[i].notify(ic[key].value)
         end
     end
 
     -- clear the contents of the interconnect
-    function public.purge() self.ic = nil end
+    function public.purge() ic = {} end
 
     return public
 end
diff --git a/scada-common/rsio.lua b/scada-common/rsio.lua
index 29acfd2..13a6d6a 100644
--- a/scada-common/rsio.lua
+++ b/scada-common/rsio.lua
@@ -123,7 +123,7 @@ function rsio.to_string(port)
     if util.is_int(port) and port > 0 and port <= #names then
         return names[port]
     else
-        return ""
+        return "UNKNOWN"
     end
 end
 
diff --git a/scada-common/tcd.lua b/scada-common/tcd.lua
index f5ff0e5..a3c920f 100644
--- a/scada-common/tcd.lua
+++ b/scada-common/tcd.lua
@@ -68,7 +68,7 @@ function tcd.handle(event)
     end
 end
 
--- identify any overdo callbacks<br>
+-- identify any overdue callbacks<br>
 -- prints to log debug output
 function tcd.diagnostics()
     for timer, entry in pairs(registry) do
diff --git a/scada-common/util.lua b/scada-common/util.lua
index 99f62a6..2d32eae 100644
--- a/scada-common/util.lua
+++ b/scada-common/util.lua
@@ -80,9 +80,9 @@ end
 ---@return string
 function util.strrep(str, n)
     local repeated = ""
-    for _ = 1, n do
-        repeated = repeated .. str
-    end
+
+    for _ = 1, n do repeated = repeated .. str end
+
     return repeated
 end
 
@@ -123,7 +123,9 @@ function util.strwrap(str, limit) return cc_strings.wrap(str, limit) end
 ---@diagnostic disable-next-line: unused-vararg
 function util.concat(...)
     local str = ""
+
     for _, v in ipairs(arg) do str = str .. util.strval(v) end
+
     return str
 end
 
@@ -322,7 +324,8 @@ end
 --- EVENT_CONSUMER: this function consumes events
 function util.nop() util.psleep(0.05) end
 
--- attempt to maintain a minimum loop timing (duration of execution)
+-- attempt to maintain a minimum loop timing (duration of execution)<br>
+-- note: will not yield for time periods less than 50ms
 ---@nodiscard
 ---@param target_timing integer minimum amount of milliseconds to wait for
 ---@param last_update integer millisecond time of last update
@@ -399,7 +402,7 @@ local function GFE(fe) return fe / 1000000000.0 end
 local function TFE(fe) return fe / 1000000000000.0 end
 local function PFE(fe) return fe / 1000000000000000.0 end
 local function EFE(fe) return fe / 1000000000000000000.0 end    -- if you accomplish this please touch grass
-local function ZFE(fe) return fe / 1000000000000000000000.0 end -- please stop
+local function ZFE(fe) return fe / 1000000000000000000000.0 end -- how & why did you do this?
 
 -- format a power value into XXX.XX UNIT format (FE, kFE, MFE, GFE, TFE, PFE, EFE, ZFE)
 ---@nodiscard