The
range of the applied Trim can be varied using configuration variable TRRG (Trim
Range) in the range +/-0.0 to 10.0 degC. The centre zero and range accuracy
of the Trim pot have been improved in version 4c1 onwards.This is the first of an evolving range of Fan Coil Controllers,
the eventual aim is to have one set of generic Fan Coil code which will run
on any of the hardware platforms. This issue uses four separate files. The driver
configuration options allow a wide range of output possibilities. Automatic
Fan Speed control is provided for multi speed fan applications.
The configuration variable structures have been upgraded to also store the units
of the parameters. This now means that temperature parameters can be displayed
in C or F on Zone Controllers ZON3c1 onwards. These changes are required for
the USA market.
The FCU controllers are registered to a Boiler Controller, this must be at least
BLRxx3a7 (latest issue hardware 'C') or Floor Controller FLR3a1. In most respects
the FCU controller behaves in a similar manner to a Slave Zone Controller, it
is registered as a Zone. One major difference is that it does not have it's
own Occupation times and so does not do it's own Optimum Start. A Zone Controller
is required to provide these facilities for any number of FCUs.
In order to talk to FCU 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 FCU'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 FCU in turn. The zone will report SLVE 2 (for
FCU 2, 3 for FCU 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 FCUs are put into the same group as the Master Zone, any number of FCUs
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 AHU can be left to control from it's own setpoint but Occupancy is controlled
from a single Zone controller by registering the FCU to the Zone. The FCU will
control to a constant Return air setpoint regardless of the heating or cooling
demands from the Zone.
If a supply air sensor is fitted then the off-coil temperature will be controlled
within the limits defined by MAXH, MINH, MAXC, MINC.
Setpoint supervision SPTY 1
This is the default mode of operation. The FCU(s) will control the return
air (during optimum start and occupation) to the setpoint defined by the Zone
Controller.
The FCU Return Air setpoints can be individually adjusted using the SPTR setpoint
trim config variable to adjust for local conditions.
If a supply air sensor is fitted then the off-coil temperature will be controlled
within the limits defined by MAXH, MINH, MAXC, MINC.
The Return air sensor is not fitted. The mode must be set
to (SPTY) 2.
Supply Temperature scheduled to Heat and Cool demands from Zone SPTY 2
If a Supply Air sensor is fitted the Fan Coil will schedule the temperature
of the supply air (off coil) according to the Heat and Cool demands from the
Zone Controller. Remember that the Zone Controller will only provide cooling
demands if it's setpoint deadband SPDB is not set to zero.
The setpoint for the Supply Air control is calculated from the MAXH, MINH config
limits for heating demands and from the MAXC, MINC limits for cooling demands.
If there is no sensor fitted 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 FCU'
to another FCU.
The supply sensor can be replaced by a switch which when
made will force the FCU to Occupied.
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
Specification of Trim pot
changed to match Sontay standard product.
If the switch is wired in series with a 1K
resistor and a 10K potentiometer Occupied/ Non occupied plus a 5 degree
trim (operational only whilst occupied) is possible. The low resistance
equates to maximum negative trim.
The
range of the applied Trim can be varied using configuration variable TRRG (Trim
Range) in the range +/-0.0 to 10.0 degC. The centre zero and range accuracy
of the Trim pot have been improved in version 4c1 onwards.
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
The Trim pot is connected to 'Input a' on the 7R Fan Coil thus leaving the option of retaining the Supply Air sensor.
See additional Fan Switch option
for 7R Fan Coil
If
the setpoint type SPTY of the controller is set to 2, this is where it receives
heating and cooling demands from the supervising Zone Controller or Fan Coil
Controller, then if the input mode INMD is set to force Occupation then an alarm
will be raised INVD which indicates Invalid Configuration settings. The Fan
Coil cannot operate without the demand signals from the Zone so forcing Occupation
is not a valid option.
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) Room controller for example, if this network
variable is non zero then this will override the automatic fan speed control.
The 7R fan coil version supports the addition of a Setpoint Trim and Fan Speed selector. The controller is designed to use the Sontay wall mounting product TT811/10K3a1. This must be connected as per the table below. For correct operation of the Fan Switch the temperature sensors should have been 'calibrated' using the built in routine and precision 10K calibration resistors.
| Sontay Terminal | SeaChange terminal | name | function |
| 1 | 15 | input B | fan speed switch |
| 2 | 16 | input B | fan speed switch |
| 3 | 13 | input A | setpoint trim |
| 4 | 14 | input A | setpoint trim |
| 5 | 11 | return air temperature | return temperature |
| 6 | 12 | return air temperature | return temperature |
The Fan Switch has five positions, off, speed 1, speed 2, speed 3 and Automatic. The default operation is as follows:-
It may be confusing to some users to find the switch set to speed 1-3 and the Fan Coil not running. To overcome this objection the controller can be switched to Dumb mode, switch 6 FSWM forces the Fan Coil to run, regardless of Occupancy signals if the switch is set to speeds 1-3.
The setpoint trim provides +/- 5 degrees trim (range is adjustable with config TRRG) to the control setpoint, connecting the trim potentiometer automatically activates the setpoint trim function. (7R version only, other versions share the input with the supply sensor and so a selection must be made using config INMD)
The external occupation connection for window contact or time clock is made to the Supply Sensor input and functions as described above.
Note the Sontay Fan speed switch will overide the Fan Speed provided by the network variable e.g. from a Room Controller, unless Auto is selected when the Fan Speed control will revert to the Room Controller or to the internal automatic fan speed routine.
There
are many ways in which a Fan Coil Controller can be brought into Occupation
the following lists them in increasing priority.
There
are multiple methods of selecting Fan Speed this lists them in increasing priority.
This allows one 'master 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 FCU, any number of Slaves
can be linked to a single Master.
If a Slave FCU is subsequently linked to a Zone Controller the link to the Master
AHU will automatically be broken.
Any FCU can act as a source of setpoint (and occupancy)
information for a group of FCUs which are all controlling to their local Return
Air sensor.
This would be useful when one FCU has a local Trim Pot (or Occupancy switch)
and the same setpoint is required on other FCUs feeding the same area of the
building.
Put the 'master' into config and 'slave' the other FCUs. The Slave FCUs will
receive the mid point setpoint (C1 SPFC plus any external Trim) of the Master,
local additional trim can be applied to each FCU using SPTR. To maintain balance
amongst the FCUs 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 FCU' within each separate space, these FCUs 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 FCUs within the area.
There are no limits on the number of FCUs which can be slaved to a 'master FCU'.
A Slave FCU can also be a 'master' to a further group of FCUs, although this
only makes sense if these FCUs are operating in mode SPTY 2;either Off Coil
only control or in Driver only mode (no sensors fitted).
Two override options are now available from Doorway.
This functions exactly the same as for a Zone Controller, Switch 1 set to zero selects Override mode and the state of switch 2 determines occupancy state.
The syntax
[Zn]W1(S)/Auto/Override/10/12/W2(S)
provides a single click to a dialog box which sets the correct state for both switches. The text can be changed to suit the application and the numbers determine the colours which are used to display the text.
Note the override mode will automatically terminate and return to Automatic when the required state for Occupancy matched the Overriden state. For example if the Fan coil is off becuase the window contact is not made, it can be Overriden ON and it will stay in Override until the normal Occupancy tests result in an on condition i.e. the window contact is fixed or the input mode INMD is changed.
This
option allows the Fan Coil outputs to be manually set for balancing or general
testing. This uses switch 5 to select manual or hand mode and the value of MANL
to set the output levels.
The syntax
[Zn]W5(S)/Hand/Auto/12/10/C83(V)
brings up a dialog box which allows Hand or Auto to be selected and also the value of the output to be entered in a text box or changed with a slider bar. The output can be set anywhere in the range 100 (full heat) to (-100) full cool. Note C83 is the fixed configuration variable MANL which is now used on all products which have universal manual code (4c1 or later).
| code | Hardware | Part Number | |
| FCUD4c1 | ACT-DIN-3R | 0006/0001 issue J12 | 512 prom |
| ACT-DIN-3T | 0018/0001 issue E5 | 512 prom | |
| FCUR4c1 | FCT-DIN-4R | 0020/0001 issue E4 | 512 prom |
| FCUF4c1 | FCU-DIN-7R | 0023/0001 issue A | 512 prom address swapped |
| FCUA4c1 | ACT-DIN-AOP | 0016/0001 issue E7 | 512 prom |
Secondary Supported Hardware (special order) |
|||
| code | Hardware | Part Number | |
| FCUB4c1 | BLR-DIN-RLY | 0004/0002 issue C5 | 512 prom address swapped |
Controllers which are intended to be used with third party binding tools can be specified to have the Software switch set to enable external binding, this is indicated by an X in the file name ahead of the issue number e.g. FCURX4b1. Fan Coil Controllers Controllers so specified also support PIR detectors to change between Standby and full Occupancy. These controllers have additional functionality as defined by this specification.
Two
Pipe OperationTwo pipe operation is enabled by setting MIDP to -1. The controller will monitor the "Flow temperature" sent by the Floor Controller and enable heating or cooling control based on whether this temperature is higher or lower than its own Occupied setpoint. Since the same valve is used for heating and cooling the driver needs to be setup to re-direct the cooling output to the heating driver. This is acheived by setting the driver types to be the same but to only set the stages on one of the drivers. See universal driver informantion.
Special
Case Two Pipe plus Electric HeaterThis is a special mode of control which is selected by setting MIDP to -2 or -3. The Heating Driver is used to control the Control Valve and the Cooling Driver is used for the Electric Boost Heater. Redirection of the control signal is handled in the application code so set the individual drivers to match the controlled loads. On a 6R board if both drivers are single stage the first Fan Speed relay will be relay C, it might be preferable to make one of the drivers 2 stage to get the Fan Speed relays on relays D,E, and F as normal. The initial 50% of the heating output is used for the control valve and the final 50% is used for the electric heater.
If MIDP is -2 the Electric Heater will only work if the overall system is in 'Heating Mode', if MIDP is -3 the Electric Heater will also be used when the system is in 'Cooling Mode' and the Fan Coil has more than 50% heating demand.
This has been included to allow hardware to be re-tested at the final booking out station and also to be easily checked at any time in the field.
The controller is put into test mode by setting config 120 to 1 or by holding the service pin down as the unit is powered up. If the later method is used then the unit will need to be re-registered after the test since this action also clears any slaving which might have been setup.
Test mode is cleared by power cycling or by setting C120 back to 0.
Test mode cycles the outputs, and flashes the leds see full test specification. The values for the analogue inputs and the potentiometer can be monitored on configs 170 onwards.
The
temperature input channels can now be calibrated using a precision 10K resistor
and Doorway. This process is carried out at the factory and would only need
to be used in the field if the firmware in the controller needed to be changed.
After calibration the measured temperatures are much more accurate, +/- 0.25
deg C in the range 10 to 30 deg C, and +/- 0.5 deg C across the whole range
0 to 80 degC. If the Sontay fan speed switch is used on the 7R fan coil then
calibration of the temperature channel used is required in order to reliably
switch the fan. Full calibration routine described
here.
Improvements
have been made to the information provided to the user by the LEDs on the Controller.
This version of the Fan Coil controller uses the extended universal driver which includes a special driver type for Heat Pumps. This allows one relay to select heating or cooling and a single bank of relays to bring on the heat pump stages.
An additional configuration variable has been included to allow for Airside Damper control. This parameter sets the nominal mid point MIDP of the damper travel, the position where no heating or cooling is provided. If this mid point value is set (not zero) then the driver parameters should be set as in the following table.
| HTYP | HSTG | CTYP | CSTG | FTYP | FSTG |
| 1 | 2 | 1 | 0 | 6 | 1 |
This will cause the cooling demands to be redirected to the same relays as the heating driver (redirected output). The Fan parameters should of course be set to the required Fan type.
Airside
Damper control is now supported on the 7R hardware set the driver parameters
as per the following table and setup MIDP as above.
| HTYP | HSTG | CTYP | CSTG | FTYP | FSTG |
| 5 | 2 | 5 | 0 | 6 | 1 |
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
if negative sets the on delay in minutes for the fan or pump
if positive sets run on time in minutes for fan or pump to run after heating shut down
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 |
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'. If Input Mode is set to 1-3 an alarm is raised
when the input state does not match that of Alarm State ALST, this allows overrides
and window contacts to be monitored at the supervisor. If the Input Mode is
set to 4, External Alarm then this alarm will shut down the Fan Coil if ALRM
is set to 2 or 3 as per the following table. This may be used for flood protection
if the condensate removal system fails.
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 | Sensor Fail or External Alarm (INMD=4) control output set to zero |
| 3 | STOP alarm or Sensor Fail or External Alarm (INMD=4), 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.
There are three plots setup as normal on the first three
'sensors'.
Plot 1 Supply air temperature
Plot 2 Return Air temperature
Plot 3 Heat/cool output -100 to +100 (negative for cooling)
The plot routine use configurable
plots.
The plots are now automatically re-scaled within the controller
to achieve the best resolution for the data recorded. This happens at the end
of every 96 readings when new maximum and minimum settings are calculated and
also if a new value is outside the current range settings.
Will support registration of up to 8 Acuators, Acuator Drivers,
Pump ChangeOvers just like a regular Zone.
Fan Coil Controllers are addressed with [Zn] where n is
the Fan Coil 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