upgrade to dual domain (4b1)
add occupaction override from Doorway(4b2)
add HAND control of outputs from Doorway (4b2)
correct sending of demands to 1 per minute (4b3)
correct response to min box volume and max box volume settings (4b3)
improve universal driver now version 4a (4b3)
add HTCT, CLCT support, allows sending of CT setpoint to Boilers and Secondary boilers
remove MXCT, MNCT(4b5)
The VAV controllers are registered in exactly the same way as Fan Coil
controllers. For the time being they are considered to be a special type of
Fan Coil controller.
In order to talk to VAV controllers
with Doorway the SLT needs to be upgraded to issue 3a5 or later. It is possible
to use the [#] addressing method (last service pin pressed) if the SLT available
is not 3a.
Zone controllers used with VAV's must be ZON3b1 or later running on latest
large memory hardware, earlier versions will not recognise FCU controllers for
registration.
The registration procedure for all modes is the same as for registering Slave
Zones to a Master Zone. Put the Master Zone Controller into config then register
each VAV in turn. The zone will report SLVE 2 (for VAV 2, 3 for VAV 3 etc.)
The Master Zone will be set automatically to SPMD 3 when a Fan Coil is
slaved to it, to allow the Fan Coils to receive the Setpoint and Occupation
information.
The VAVs are put into the same group as the Master Zone, any number of VAVs
can be linked to a single Master.
The Return air sensor must be fitted and the SPTY must be set to 0 or 1.
Note the Occupation and Setpoint data is only updated every minute so be patient
when commissioning, operationally this is OK because the change will normally
come from the Optimum start routines which are checked every minute. If the
setpoint is changed on the Master Zone (with the knob) the new setpoint is sent
straightaway.
Occupancy control SPTY 0
The VAV can be left to control from it's own setpoint but Occupancy is controlled
from a single Zone controller by registering the VAV to the Zone. The VAV will
control to a constant Return air setpoint regardless of the heating or cooling
demands from the Zone.
Setpoint supervision SPTY 1
This is the default mode of operation. The VAV(s) will control the return
air (during optimum start and occupation) to the setpoint defined by the Zone
Controller.
The VAV Return Air setpoints can be individually adjusted using the SPTR setpoint
trim config variable to adjust for local conditions.
The Return air sensor is not fitted.
The mode must be set to (SPTY) 2.
Box volume slaved to Zone or master VAV heat and cool demands SPTY 2
The Heat or Cool demand from the Zone will be used to directly control the
output stages, this mode is also used to 'slave a VAV' to another VAV (or FCU).
If the controller is regulating the supply of air from a plenum with a single damper (RiverMill House) the temperature of this plenham can be reported to the controller and the damper prevented from opening if the plenham temperature is not suitable for the control mode currently required. For example if the plenham is hot but the controller is being asked to cool the room. The Plenham temperature is compared with the current space setpoint setting (SPFC+/-SPDB/2) and if the temperature is unsuitable the damper is maintained at the minimum volume (MINV fresh air) setting. This mode can be selected by setting the Re Heat REHT config variable to -1.
The supply sensor can be replaced by a switch which when made will force the
FCU to Occupied. On FCF or BLR boards the external connection is made to 'input
a', thus retaining the use of the supply sensor.
This is achieved by adding an extra config variable input mode INMD. The following
values are supported.
0 normal operation input measures Off Coil temperature
1 Occupied is External AND normal occupation (window contact)
2 Occupied is External OR normal occupation (outside normal hours)
3 Occupation controlled by external signal only
4 Input used as an external alarm, alarm state defined by ALST
If the switch is wired in series with a 10K resistor and a 10K potentiometer
Occupied/ Non occupied plus a 5 degree trim (operational only whilst occupied)
is possible. The trim is slightly non linear (the applied resistance is affected
by the parallel resistance on the board which helps linearise the thermistor
when fitted, mechanical centre position of the pot gives -0.7C) The zero point
can be adjusted to give the correct (0 trim) by backing off any error using
the software trim SPTR. Suggest pot is marked Hotter/Colder or +/- !
A resistance between 0 and 20K ohm will be considered to be Occupied, non Occupied
is guaranteed for resistance values above 100K. The voltage generated by the
pot will be converted to a setpoint Trim only for control modes SPTY 0
or 1
This allows one 'master VAV (or FCU)' to provide the Return Air control for
a large space and to send its HeatOp and CoolOp outputs to one or more 'Slave
FCU's'
The Master must be operating in mode SPTY 0 or 1, i.e. must be measuring and
controlling Return temperature.
The 'Slave' must be operating in mode SPTY 2. The registration process involves
putting the master into config mode and then pressing the registration button
on all the 'Slave FCU's'.
The Slaves are put into the same group as the Master VAV, any number of Slaves
can be linked to a single Master.
If a Slave VAV is subsequently linked to a Zone Controller the link to the Master
VAV will automatically be broken.
Any VAV can act as a source of setpoint (and occupancy) information for a group
of VAVs which are all controlling to their local Return Air sensor.
This would be useful when one VAV has a local Trim Pot (or Occupancy switch)
and the same setpoint is required on other VAVs feeding the same area of the
building.
Put the 'master' into config and 'slave' the other VAVs. The Slave VAVs will
receive the mid point setpoint (C1 SPFC plus any external Trim) of the
Master, local additional trim can be applied to each VAV using SPTR.
To maintain balance amongst the VAVs the setpoint deadband SPDB should
be the same in all units within the group.
In this way a Zone Controller can provide Setpoint and/or Occupancy information
to a 'master VAV' within each separate space, these VAVs can have local User
Adjustments (for the cheapskates who won't buy Zone Controllers) or Occupancy
overrides, these modified conditions are then sent to all VAVs within the area.
There are no limits on the number of VAVs which can be slaved to a 'master VAV'.
A Slave VAV can also be a 'master' to a further group of VAVs, although this
only makes sense if these VAVs are operating in mode SPTY 2;either Off Coil
only control or in Driver only mode (no sensors fitted).
The controller will automatically control fan speed, if the multi-speed fan
driver is used. If either the heating or cooling demand is greater than 90%
for a period longer than FPRD (seconds/10 to match other periods) then the fan
speed will be incremented up to the next speed. If both the heating and cooling
demand is less than 10% then the Fan Speed is reduced after the same delay time.
While occupied the controller will maintain a minimum of Fan Speed 1.
Provision is made for the fan speed to be controlled from a network variable
(nviFanSpeed), from a (hotel style) zone controller for example, if this network
variable is non zero then this will override the automatic fan speed control.
The FCU controller supports sensor
fail SENF alarm, this is raised if the Return Air sensor fails and the FCU is
in a mode which requires the Return Air temperature. The Input Mode can also
be set up to generate an alarm for either a short or open circuit on terminals
'temp a', see later.
Alarm mode and Alarm State config variables have been added to the config variable
list.
| ALMD | action |
| 0 | alarms ignored |
| 1 | alarms reported no other action |
| 2 | control output set to zero on alarm |
| 3 | STOP alarm recognised, control set to zero |
Alarm State determines which
input state 0 or 1 is considered to be the alarm condition when using external
input for the alarm as set by INMD.
| code | Hardware | Part Number | |
| FCUV3d1 | ACT-DIN-AOP | 0016/0003 issue E3 | 512 prom |
This controller uses the universal output driver version 4a. which allows a range of output possibilities, although the VAV controller is primariliy designed to run on an AOP board other hardware options are possible.
The controller defaults to two analogue outputs, channel one for heating and channel two for box volume. The actual voltage levels which represent 0 and 100% can be set using MXVA, MNVA, MXVB, MNVB.
The maximum and minimum Box volumes can be set using MAXV and MINV.
If the VAV needs to control a re-heater
when in heating mode, this is activated by setting the config variable REHT
to a value in the range 1 to 99%. The value set determines the maximum box volume
when in heating, this allows the heating mode to be more energy efficient by
heating a smaller volume of cold air. When using the Re Heat function the reheater
is connected to the Heating output HTYP and the Box volume control is connected
to the cooling output. Cooling operates by varing the air volume between minimum
volume and maximum volume, heating varies the heating output from 0 to 100%
and the volume output from minimum volume to the re heat volume REHT.
These have been changed to a new more flexible approach. A single parameter
for each driver type is provided which sets up the on delay or run on time for
the fan or pump.
HDLY
Typically negative values will be used for wet batteries to provide start up
protection against frost and positive (run on-) values would be used with electric
heating batteries.
The same features are available for
cooling using CDLY.
The selection of OCC or OSS is now
made by setting OCCO to 1 on controllers where the control is only required
when the building is in occupation. The default is for control during OSS and
OCC.
This is defined with a config parameter
FRPT and it defines the controllers action when it receives a 'frost alarm'
from the boiler controller.
| FRPT | action |
| 0 | no action (default) |
| 1 | heating output to 50% |
| 2 | heating output to 50% and pump/fan enabled |
There are three plots setup as normal on the first three 'sensors'.
Plot 1 Air Flow 0-100%
Plot 2 Return Air temperature
Plot 3 Heat/cool output -100 to +100 (negative for cooling)
The plot routine has been enhanced and the plotting period is now selectable
see configurable plots for details.
Will support registration of up to 8 Acuators, Acuator Drivers, Pump ChangeOvers
just like a regular Zone. This is not supported in version 3ax 0006 issue D
boards due to shortage of memory.
VAV Controllers are addressed with [Zn] where n is the VAV Zone number 1-200.
[Fn] is also supported.
Sub modules are addressed as follows
Actuators [Z1Am] m=1 to 8
Item codes follow the normal conventions