diff --git a/supervisor/session/rtu.lua b/supervisor/session/rtu.lua
index 30e9432..f8cd3f4 100644
--- a/supervisor/session/rtu.lua
+++ b/supervisor/session/rtu.lua
@@ -60,6 +60,7 @@ function rtu.new_session(id, in_queue, out_queue, advertisement, facility_units)
         id = id,
         in_q = in_queue,
         out_q = out_queue,
+        modbus_q = mqueue.new(),
         f_units = facility_units,
         advert = advertisement,
         -- connection properties
@@ -107,6 +108,8 @@ function rtu.new_session(id, in_queue, out_queue, advertisement, facility_units)
                 rsio = self.advert[i][4]
             }
 
+            local target_unit = self.f_units[unit_advert.reactor]   ---@type reactor_unit
+
             local u_type = unit_advert.type
 
             -- validate unit advertisement
@@ -133,35 +136,39 @@ function rtu.new_session(id, in_queue, out_queue, advertisement, facility_units)
                 -- validation fail
             elseif u_type == RTU_UNIT_TYPES.REDSTONE then
                 -- redstone
-                unit, rs_in_q = svrs_redstone.new(self.id, i, unit_advert, self.out_q)
+                unit, rs_in_q = svrs_redstone.new(self.id, i, unit_advert, self.modbus_q)
             elseif u_type == RTU_UNIT_TYPES.BOILER then
                 -- boiler
-                unit = svrs_boiler.new(self.id, i, unit_advert, self.out_q)
+                unit = svrs_boiler.new(self.id, i, unit_advert, self.modbus_q)
+                target_unit.add_boiler(unit)
             elseif u_type == RTU_UNIT_TYPES.BOILER_VALVE then
                 -- boiler (Mekanism 10.1+)
-                unit = svrs_boilerv.new(self.id, 1, unit_advert, self.out_q)
+                unit = svrs_boilerv.new(self.id, i, unit_advert, self.modbus_q)
+                target_unit.add_boiler(unit)
             elseif u_type == RTU_UNIT_TYPES.TURBINE then
                 -- turbine
-                unit = svrs_turbine.new(self.id, i, unit_advert, self.out_q)
+                unit = svrs_turbine.new(self.id, i, unit_advert, self.modbus_q)
+                target_unit.add_turbine(unit)
             elseif u_type == RTU_UNIT_TYPES.TURBINE_VALVE then
                 -- turbine (Mekanism 10.1+)
-                unit, tbv_in_q = svrs_turbinev.new(self.id, i, unit_advert, self.out_q)
+                unit, tbv_in_q = svrs_turbinev.new(self.id, i, unit_advert, self.modbus_q)
+                target_unit.add_turbine(unit)
                 self.turbine_cmd_capable = true
             elseif u_type == RTU_UNIT_TYPES.EMACHINE then
                 -- mekanism [energy] machine
-                unit = svrs_emachine.new(self.id, i, unit_advert, self.out_q)
+                unit = svrs_emachine.new(self.id, i, unit_advert, self.modbus_q)
             elseif u_type == RTU_UNIT_TYPES.IMATRIX then
                 -- induction matrix
-                unit = svrs_imatrix.new(self.id, i, unit_advert, self.out_q)
+                unit = svrs_imatrix.new(self.id, i, unit_advert, self.modbus_q)
             elseif u_type == RTU_UNIT_TYPES.SPS then
                 -- super-critical phase shifter
-                unit = svrs_sps.new(self.id, i, unit_advert, self.out_q)
+                unit = svrs_sps.new(self.id, i, unit_advert, self.modbus_q)
             elseif u_type == RTU_UNIT_TYPES.SNA then
                 -- solar neutron activator
-                unit = svrs_sna.new(self.id, i, unit_advert, self.out_q)
+                unit = svrs_sna.new(self.id, i, unit_advert, self.modbus_q)
             elseif u_type == RTU_UNIT_TYPES.ENV_DETECTOR then
                 -- environment detector
-                unit = svrs_envd.new(self.id, i, unit_advert, self.out_q)
+                unit = svrs_envd.new(self.id, i, unit_advert, self.modbus_q)
             else
                 log.error(log_header .. "bad advertisement: encountered unsupported RTU type")
             end
@@ -213,6 +220,17 @@ function rtu.new_session(id, in_queue, out_queue, advertisement, facility_units)
         end
     end
 
+    -- send a MODBUS packet
+    ---@param m_pkt modbus_packet MODBUS packet
+    local function _send_modbus(m_pkt)
+        local s_pkt = comms.scada_packet()
+
+        s_pkt.make(self.seq_num, PROTOCOLS.MODBUS_TCP, m_pkt.raw_sendable())
+
+        self.out_q.push_packet(s_pkt)
+        self.seq_num = self.seq_num + 1
+    end
+
     -- send a SCADA management packet
     ---@param msg_type SCADA_MGMT_TYPES
     ---@param msg table
@@ -387,11 +405,29 @@ function rtu.new_session(id, in_queue, out_queue, advertisement, facility_units)
             end
 
             self.periodics.last_update = util.time()
+
+            ----------------------------------------------
+            -- pass MODBUS packets on to main out queue --
+            ----------------------------------------------
+
+            for _ = 1, self.modbus_q.length() do
+                -- get the next message
+                local msg = self.modbus_q.pop()
+
+                if msg ~= nil then
+                    if msg.qtype == mqueue.TYPE.PACKET then
+                        _send_modbus(msg.message)
+                    end
+                end
+            end
         end
 
         return self.connected
     end
 
+    -- handle initial advertisement
+    _handle_advertisement()
+
     return public
 end
 
diff --git a/supervisor/session/rtu/boiler.lua b/supervisor/session/rtu/boiler.lua
index 5daef5e..7aa25f0 100644
--- a/supervisor/session/rtu/boiler.lua
+++ b/supervisor/session/rtu/boiler.lua
@@ -108,7 +108,7 @@ function boiler.new(session_id, unit_id, advert, out_queue)
     -- handle a packet
     ---@param m_pkt modbus_frame
     function public.handle_packet(m_pkt)
-        local txn_type = self.session.try_resolve(m_pkt.txn_id)
+        local txn_type = self.session.try_resolve(m_pkt)
         if txn_type == false then
             -- nothing to do
         elseif txn_type == TXN_TYPES.BUILD then
diff --git a/supervisor/session/rtu/boilerv.lua b/supervisor/session/rtu/boilerv.lua
index 16125f0..bea740a 100644
--- a/supervisor/session/rtu/boilerv.lua
+++ b/supervisor/session/rtu/boilerv.lua
@@ -1,6 +1,7 @@
 local comms        = require("scada-common.comms")
 local log          = require("scada-common.log")
 local types        = require("scada-common.types")
+local util         = require("scada-common.util")
 
 local unit_session = require("supervisor.session.rtu.unit_session")
 
@@ -60,8 +61,8 @@ function boilerv.new(session_id, unit_id, advert, out_queue)
                 length = 0,
                 width = 0,
                 height = 0,
-                min_pos = 0,
-                max_pos = 0,
+                min_pos = { x = 0, y = 0, z = 0 },  ---@type coordinate
+                max_pos = { x = 0, y = 0, z = 0 },  ---@type coordinate
                 boil_cap = 0.0,
                 steam_cap = 0,
                 water_cap = 0,
@@ -76,16 +77,16 @@ function boilerv.new(session_id, unit_id, advert, out_queue)
                 boil_rate = 0.0
             },
             tanks = {
-                steam = {},         ---@type tank_fluid
+                steam = { type = "mekanism:empty_gas", amount = 0 }, ---@type tank_fluid
                 steam_need = 0,
                 steam_fill = 0.0,
-                water = {},         ---@type tank_fluid
+                water = { type = "mekanism:empty_gas", amount = 0 }, ---@type tank_fluid
                 water_need = 0,
                 water_fill = 0.0,
-                hcool = {},         ---@type tank_fluid
+                hcool = { type = "mekanism:empty_gas", amount = 0 }, ---@type tank_fluid
                 hcool_need = 0,
                 hcool_fill = 0.0,
-                ccool = {},         ---@type tank_fluid
+                ccool = { type = "mekanism:empty_gas", amount = 0 }, ---@type tank_fluid
                 ccool_need = 0,
                 ccool_fill = 0.0
             }
@@ -105,19 +106,19 @@ function boilerv.new(session_id, unit_id, advert, out_queue)
     -- query the build of the device
     local function _request_build()
         -- read input registers 1 through 13 (start = 1, count = 13)
-        self.session.send_request(TXN_TYPES.BUILD, MODBUS_FCODE.READ_INPUT_REGS, { 1, 7 })
+        self.session.send_request(TXN_TYPES.BUILD, MODBUS_FCODE.READ_INPUT_REGS, { 1, 13 })
     end
 
     -- query the state of the device
     local function _request_state()
-        -- read input registers 14 through 16 (start = 14, count = 2)
+        -- read input registers 14 through 15 (start = 14, count = 2)
         self.session.send_request(TXN_TYPES.STATE, MODBUS_FCODE.READ_INPUT_REGS, { 14, 2 })
     end
 
     -- query the tanks of the device
     local function _request_tanks()
-        -- read input registers 17 through 29 (start = 17, count = 12)
-        self.session.send_request(TXN_TYPES.TANKS, MODBUS_FCODE.READ_INPUT_REGS, { 17, 12 })
+        -- read input registers 16 through 27 (start = 16, count = 12)
+        self.session.send_request(TXN_TYPES.TANKS, MODBUS_FCODE.READ_INPUT_REGS, { 16, 12 })
     end
 
     -- PUBLIC FUNCTIONS --
@@ -125,7 +126,7 @@ function boilerv.new(session_id, unit_id, advert, out_queue)
     -- handle a packet
     ---@param m_pkt modbus_frame
     function public.handle_packet(m_pkt)
-        local txn_type = self.session.try_resolve(m_pkt.txn_id)
+        local txn_type = self.session.try_resolve(m_pkt)
         if txn_type == false then
             -- nothing to do
         elseif txn_type == TXN_TYPES.FORMED then
diff --git a/supervisor/session/rtu/emachine.lua b/supervisor/session/rtu/emachine.lua
index db8a17b..e31c2af 100644
--- a/supervisor/session/rtu/emachine.lua
+++ b/supervisor/session/rtu/emachine.lua
@@ -79,7 +79,7 @@ function emachine.new(session_id, unit_id, advert, out_queue)
     -- handle a packet
     ---@param m_pkt modbus_frame
     function public.handle_packet(m_pkt)
-        local txn_type = self.session.try_resolve(m_pkt.txn_id)
+        local txn_type = self.session.try_resolve(m_pkt)
         if txn_type == false then
             -- nothing to do
         elseif txn_type == TXN_TYPES.BUILD then
diff --git a/supervisor/session/rtu/envd.lua b/supervisor/session/rtu/envd.lua
index f502e17..93968a9 100644
--- a/supervisor/session/rtu/envd.lua
+++ b/supervisor/session/rtu/envd.lua
@@ -62,7 +62,7 @@ function envd.new(session_id, unit_id, advert, out_queue)
     -- handle a packet
     ---@param m_pkt modbus_frame
     function public.handle_packet(m_pkt)
-        local txn_type = self.session.try_resolve(m_pkt.txn_id)
+        local txn_type = self.session.try_resolve(m_pkt)
         if txn_type == false then
             -- nothing to do
         elseif txn_type == TXN_TYPES.RAD then
diff --git a/supervisor/session/rtu/imatrix.lua b/supervisor/session/rtu/imatrix.lua
index 965b57b..e6a9513 100644
--- a/supervisor/session/rtu/imatrix.lua
+++ b/supervisor/session/rtu/imatrix.lua
@@ -112,7 +112,7 @@ function imatrix.new(session_id, unit_id, advert, out_queue)
     -- handle a packet
     ---@param m_pkt modbus_frame
     function public.handle_packet(m_pkt)
-        local txn_type = self.session.try_resolve(m_pkt.txn_id)
+        local txn_type = self.session.try_resolve(m_pkt)
         if txn_type == false then
             -- nothing to do
         elseif txn_type == TXN_TYPES.FORMED then
diff --git a/supervisor/session/rtu/redstone.lua b/supervisor/session/rtu/redstone.lua
index ba01400..7ebd28b 100644
--- a/supervisor/session/rtu/redstone.lua
+++ b/supervisor/session/rtu/redstone.lua
@@ -144,7 +144,7 @@ function redstone.new(session_id, unit_id, advert, out_queue)
     -- handle a packet
     ---@param m_pkt modbus_frame
     function public.handle_packet(m_pkt)
-        local txn_type = self.session.try_resolve(m_pkt.txn_id)
+        local txn_type = self.session.try_resolve(m_pkt)
         if txn_type == false then
             -- nothing to do
         elseif txn_type == TXN_TYPES.DI_READ then
diff --git a/supervisor/session/rtu/sna.lua b/supervisor/session/rtu/sna.lua
index ccfac69..2d7f885 100644
--- a/supervisor/session/rtu/sna.lua
+++ b/supervisor/session/rtu/sna.lua
@@ -97,7 +97,7 @@ function sna.new(session_id, unit_id, advert, out_queue)
     -- handle a packet
     ---@param m_pkt modbus_frame
     function public.handle_packet(m_pkt)
-        local txn_type = self.session.try_resolve(m_pkt.txn_id)
+        local txn_type = self.session.try_resolve(m_pkt)
         if txn_type == false then
             -- nothing to do
         elseif txn_type == TXN_TYPES.BUILD then
diff --git a/supervisor/session/rtu/sps.lua b/supervisor/session/rtu/sps.lua
index c2180d9..18ad727 100644
--- a/supervisor/session/rtu/sps.lua
+++ b/supervisor/session/rtu/sps.lua
@@ -117,7 +117,7 @@ function sps.new(session_id, unit_id, advert, out_queue)
     -- handle a packet
     ---@param m_pkt modbus_frame
     function public.handle_packet(m_pkt)
-        local txn_type = self.session.try_resolve(m_pkt.txn_id)
+        local txn_type = self.session.try_resolve(m_pkt)
         if txn_type == false then
             -- nothing to do
         elseif txn_type == TXN_TYPES.FORMED then
diff --git a/supervisor/session/rtu/turbine.lua b/supervisor/session/rtu/turbine.lua
index ab63fed..7fc58f8 100644
--- a/supervisor/session/rtu/turbine.lua
+++ b/supervisor/session/rtu/turbine.lua
@@ -104,7 +104,7 @@ function turbine.new(session_id, unit_id, advert, out_queue)
     -- handle a packet
     ---@param m_pkt modbus_frame
     function public.handle_packet(m_pkt)
-        local txn_type = self.session.try_resolve(m_pkt.txn_id)
+        local txn_type = self.session.try_resolve(m_pkt)
         if txn_type == false then
             -- nothing to do
         elseif txn_type == TXN_TYPES.BUILD then
diff --git a/supervisor/session/rtu/turbinev.lua b/supervisor/session/rtu/turbinev.lua
index b31cb7c..56d43ef 100644
--- a/supervisor/session/rtu/turbinev.lua
+++ b/supervisor/session/rtu/turbinev.lua
@@ -70,6 +70,7 @@ function turbinev.new(session_id, unit_id, advert, out_queue)
         in_q = mqueue.new(),
         has_build = false,
         periodics = {
+            next_formed_req = 0,
             next_build_req = 0,
             next_state_req = 0,
             next_tanks_req = 0
@@ -81,8 +82,8 @@ function turbinev.new(session_id, unit_id, advert, out_queue)
                 length = 0,
                 width = 0,
                 height = 0,
-                min_pos = 0,
-                max_pos = 0,
+                min_pos = { x = 0, y = 0, z = 0 },  ---@type coordinate
+                max_pos = { x = 0, y = 0, z = 0 },  ---@type coordinate
                 blades = 0,
                 coils = 0,
                 vents = 0,
@@ -101,7 +102,7 @@ function turbinev.new(session_id, unit_id, advert, out_queue)
                 dumping_mode = DUMPING_MODE.IDLE    ---@type DUMPING_MODE
             },
             tanks = {
-                steam = 0,
+                steam = { type = "mekanism:empty_gas", amount = 0 }, ---@type tank_fluid
                 steam_need = 0,
                 steam_fill = 0.0,
                 energy = 0,
@@ -163,9 +164,17 @@ function turbinev.new(session_id, unit_id, advert, out_queue)
     -- handle a packet
     ---@param m_pkt modbus_frame
     function public.handle_packet(m_pkt)
-        local txn_type = self.session.try_resolve(m_pkt.txn_id)
+        local txn_type = self.session.try_resolve(m_pkt)
         if txn_type == false then
             -- nothing to do
+        elseif txn_type == TXN_TYPES.FORMED then
+            -- formed response
+            -- load in data if correct length
+            if m_pkt.length == 1 then
+                self.db.formed = m_pkt.data[1]
+            else
+                log.debug(log_tag .. "MODBUS transaction reply length mismatch (" .. TXN_TAGS[txn_type] .. ")")
+            end
         elseif txn_type == TXN_TYPES.BUILD then
             -- build response
             if m_pkt.length == 15 then
diff --git a/supervisor/session/rtu/txnctrl.lua b/supervisor/session/rtu/txnctrl.lua
index 2ebb526..a1f3b4b 100644
--- a/supervisor/session/rtu/txnctrl.lua
+++ b/supervisor/session/rtu/txnctrl.lua
@@ -19,6 +19,7 @@ function txnctrl.new()
     local public = {}
 
     local insert = table.insert
+    local remove = table.remove
 
     -- get the length of the transaction list
     function public.length()
@@ -55,8 +56,9 @@ function txnctrl.new()
 
         for i = 1, public.length() do
             if self.list[i].txn_id == txn_id then
-                txn_type = self.list[i].txn_type
-                self.list[i] = nil
+                local entry = remove(self.list, i)
+                txn_type = entry.txn_type
+                break
             end
         end
 
diff --git a/supervisor/session/rtu/unit_session.lua b/supervisor/session/rtu/unit_session.lua
index ed2f027..3a70f26 100644
--- a/supervisor/session/rtu/unit_session.lua
+++ b/supervisor/session/rtu/unit_session.lua
@@ -1,6 +1,7 @@
 local comms   = require("scada-common.comms")
 local log     = require("scada-common.log")
 local types   = require("scada-common.types")
+local util    = require("scada-common.util")
 
 local txnctrl = require("supervisor.session.rtu.txnctrl")
 
@@ -57,7 +58,7 @@ function unit_session.new(unit_id, advert, out_queue, log_tag, txn_tags)
         if m_pkt.scada_frame.protocol() == PROTOCOLS.MODBUS_TCP then
             if m_pkt.unit_id == self.unit_id then
                 local txn_type = self.transaction_controller.resolve(m_pkt.txn_id)
-                local txn_tag = " (" .. self.txn_tags[txn_type] .. ")"
+                local txn_tag = " (" .. util.strval(self.txn_tags[txn_type]) ..  ")"
 
                 if bit.band(m_pkt.func_code, MODBUS_FCODE.ERROR_FLAG) ~= 0 then
                     -- transaction incomplete or failed
diff --git a/supervisor/session/unit.lua b/supervisor/session/unit.lua
index 6cd3a5a..95fa035 100644
--- a/supervisor/session/unit.lua
+++ b/supervisor/session/unit.lua
@@ -17,7 +17,8 @@ local DT_KEYS = {
     BoilerSteam  = "BST",
     BoilerCCool  = "BCC",
     BoilerHCool  = "BHC",
-    TurbineSteam = "TST"
+    TurbineSteam = "TST",
+    TurbinePower = "TPR"
 }
 
 -- create a new reactor unit
@@ -135,22 +136,21 @@ function unit.new(for_reactor, num_boilers, num_turbines)
 
         for i = 1, #self.boilers do
             local boiler = self.boilers[i]  ---@type unit_session
-            local db = boiler.get_db()      ---@type boiler_session_db
+            local db = boiler.get_db()      ---@type boilerv_session_db
 
-            ---@todo Mekanism 10.1+ will change water/steam to need .amount
-            _compute_dt(DT_KEYS.BoilerWater .. boiler.get_device_idx(), db.tanks.water)
-            _compute_dt(DT_KEYS.BoilerSteam .. boiler.get_device_idx(), db.tanks.steam)
+            _compute_dt(DT_KEYS.BoilerWater .. boiler.get_device_idx(), db.tanks.water.amount)
+            _compute_dt(DT_KEYS.BoilerSteam .. boiler.get_device_idx(), db.tanks.steam.amount)
             _compute_dt(DT_KEYS.BoilerCCool .. boiler.get_device_idx(), db.tanks.ccool.amount)
             _compute_dt(DT_KEYS.BoilerHCool .. boiler.get_device_idx(), db.tanks.hcool.amount)
         end
 
         for i = 1, #self.turbines do
             local turbine = self.turbines[i]    ---@type unit_session
-            local db = turbine.get_db()         ---@type turbine_session_db
+            local db = turbine.get_db()         ---@type turbinev_session_db
 
-            _compute_dt(DT_KEYS.TurbineSteam .. turbine.get_device_idx(), db.tanks.steam)
-            ---@todo Mekanism 10.1+ needed
-            -- _compute_dt(DT_KEYS.TurbinePower .. turbine.get_device_idx(), db.?)
+            _compute_dt(DT_KEYS.TurbineSteam .. turbine.get_device_idx(), db.tanks.steam.amount)
+            ---@todo unused currently?
+            _compute_dt(DT_KEYS.TurbinePower .. turbine.get_device_idx(), db.tanks.energy)
         end
     end
 
@@ -242,10 +242,12 @@ function unit.new(for_reactor, num_boilers, num_turbines)
             local idx = boiler.get_device_idx()
             local db = boiler.get_db()      ---@type boiler_session_db
 
+            local gaining_hc = _get_dt(DT_KEYS.BoilerHCool .. idx) > 0 or db.tanks.hcool_fill == 1
+
             -- gaining heated coolant
-            cfmismatch = cfmismatch or _get_dt(DT_KEYS.BoilerHCool .. idx) > 0 or db.tanks.hcool_fill == 1
+            cfmismatch = cfmismatch or gaining_hc
             -- losing cooled coolant
-            cfmismatch = cfmismatch or _get_dt(DT_KEYS.BoilerCCool .. idx) < 0 or db.tanks.ccool_fill == 0
+            cfmismatch = cfmismatch or _get_dt(DT_KEYS.BoilerCCool .. idx) < 0 or (gaining_hc and db.tanks.ccool_fill == 0)
         end
 
         self.db.annunciator.CoolantFeedMismatch = cfmismatch
@@ -264,7 +266,7 @@ function unit.new(for_reactor, num_boilers, num_turbines)
 
         -- go through turbines for stats and online
         for i = 1, #self.turbines do
-            local session = self.turbine[i]     ---@type unit_session
+            local session = self.turbines[i]    ---@type unit_session
             local turbine = session.get_db()    ---@type turbine_session_db
 
             total_flow_rate = total_flow_rate + turbine.state.flow_rate
@@ -329,6 +331,8 @@ function unit.new(for_reactor, num_boilers, num_turbines)
 
     -- PUBLIC FUNCTIONS --
 
+    -- ADD/LINK DEVICES --
+
     -- link the PLC
     ---@param plc_session plc_session_struct
     function public.link_plc_session(plc_session)
@@ -388,6 +392,8 @@ function unit.new(for_reactor, num_boilers, num_turbines)
         table.insert(self.redstone[field], accessor)
     end
 
+    -- UPDATE SESSION --
+
     -- update (iterate) this unit
     function public.update()
         -- unlink PLC if session was closed
@@ -403,6 +409,16 @@ function unit.new(for_reactor, num_boilers, num_turbines)
         _update_annunciator()
     end
 
+    -- COMMAND UNIT --
+
+    -- SCRAM reactor
+    function public.scram()
+        if self.plc_s ~= nil then
+        end
+    end
+
+    -- READ STATES/PROPERTIES --
+
     -- get build properties of all machines
     function public.get_build()
         local build = {}
diff --git a/supervisor/startup.lua b/supervisor/startup.lua
index ea313a4..c7d4072 100644
--- a/supervisor/startup.lua
+++ b/supervisor/startup.lua
@@ -13,7 +13,7 @@ local svsessions = require("supervisor.session.svsessions")
 local config     = require("supervisor.config")
 local supervisor = require("supervisor.supervisor")
 
-local SUPERVISOR_VERSION = "beta-v0.5.10"
+local SUPERVISOR_VERSION = "beta-v0.5.11"
 
 local print = util.print
 local println = util.println