| Software issue DHW Controller 4a4 |
add HAND mode for manual control from Doorway
The controller functions have not changed markedly since the last 3d2 issue except for adding the above support. One noticable change is that the heat source can no longer be set to -1 to indicated sending a constanst temperature setpoint to the Boiler controller. A new variable has been added HTCT which if non zero forces the controller to send a CT setpoint to the selected heat source. The value of HTCT also defines the minimum CT setpoint sent when the controller is demanding heat. The intention is that other heat sources will be able to receive CT setpoints in addition to heat demand signals where this is more appropriate.
| file name | hardware | part number | issue |
| DHWD4a4 | ACT-DIN-RLY ACT-DIN-TOP |
0006/0001 0018/0001 |
J12 B |
| DHWA4a4 | ACT-DIN-AOP | 0016/0001 | E |
| Special order only DHWB4a1 |
BLR-DIN-RLY | 0004/0002 | C |
The control mode is selected using SPTY configuration variable.
| 0 | Occupation times slaved from a Master Zone Controller (default). The start and stop time for the DHW controller can be modified with respect to the times from the zone controller using AJST and AJSP config variables, see later. |
| 1 | Setpoint slaved from a Zone Controller which must be software issue 3c6 or later. |
| 2 | Occupancy controlled by one or more zones registered to the DHW controller. The Zone Controllers must be software issue 3c6 or later. |
For modes 0 and 1 the Master Zone Controller is put into config mode and the DHW controller is registered as a slave by pressing the registration button. The Master Zone Controller will display SLVE 2 etc to show the slave link has been made. For mode 2, register the DHW controller to the Boiler then place it in config mode. Press the registration button on all zones which need to be linked to this DHW
It is also possible to set an Occupation link from this DHW controller to another controller which supports Occupation links, e.g. an AHU controller or another DHW controller. To link to another DHW controller follow the same proceedure as with a zone. These links can also be set manually, if the target controller is in the same domain, by setting the OCDS config parameter to 100+zone number of the target DHW controller. So if the target DHW controller is zone 6, set the sending DHW controller OCDS to 106. The target DHW controller must be in control mode SPTY 2 to act on the Occupation network variable. The sending controller (provided it is issue 4a1 or later code) will show that the link has been made by flashing the temperature led 'green'. The number of flashes will match the target zone number up to a maximum of 20 flashes.
These Occupation links may be made between controllers on different domains in this case the OCDS value is Domain * 1000 plus the occupation destination number. e.g. 2107 Zone 7 on Domain 2.
The second driver channel, usually used for cooling, is used to control the Electric Heater. If this option is not required set the driver type CTYP to zero.
The Immersion heater will be used when the Outside
Temperature is above the Summer Temperature SUMR AND the flow temperature from the
appropriate heat source is below the Low Flow temperature LOFL.
The immersion is also used to 'boost' the DHW
recovery time if after 15 minutes the Boiler Flow temperature is not higher than the DHW
temperature and the DHW control loop is still calling for maximum heat. Boost is disabled
if the Outside temperature is above the 'summer temperature'.
The heating output can be further controlled using the configuration variable VMDE valve mode which has three settings
| 0 | DHW valve stays closed until boiler flow temperature greater than current DHW temperature. |
| 1 | boiler flow temperature ignored, default setting |
| 2 | Designed for systems where the DHW is
heated from a Variable temperature circuit, if the VT temperature is higher than the DHW
temperature it is used otherwise the water circuit is closed and the Electric heater used.
Note set heat source to zero for this option because it is not appropriate for the DHW
demand to influence the Boiler Controller. |
The pump is controlled using the third driver, FTYP
etc and can be made to run on or start after the heating is applied by setting HDLY.
Negative values for HDLY will start the pump the defined number of minutes after the
heating driver has been enabled, positive values will cause run on after the heating
output shuts down. If the immersion output is used CDLY is used to set the pump
characteristics to be used with the electric heater. If OCCO is set then the pump will
only run during the Occupied period.
These routines have been extended to cope with heating or cooling starts( DHW does not use the optimum cooling but it's there in order to standardise the code), maximum optimum start time MXOS applies for heating or cooling starts. The allowable error (droop) to terminate Optimum start can now be set on a config variable OPTE.
The Optimum off routines have been re-instated and
improved. Maximum Optimum Off time MXOF applies to cooling or heating conditions. When
Optimum off is invoked the control deadband is increased to the 'standby setting' see
SBDB. If the control calls for heat or cool before the end of occupation then the optimum
off constant is modified accordingly, otherwise the actual temperature at the end of
occupation is used to adapt the optimum off constant. Optimum off can be disabled by
setting MXOF to 0. During Optimum off the controller remains occupied from the point of
view of any downstream plant so Air plant will normally continue to run.
A new config variable has been added which allows a
more rigorous frost protection routine to be used this is the same as the fabric
protection routine used on Zone Controllers. If the DHW measured temperature falls below
the non-occupied setpoint then the controller switches to 'fabric protect mode' the
controller becomes 'occupied' . The controller remains in this mode until the temperature
has risen by the amount specified by the new config variable FRSE fabric rise, at which
point the controller reverts to non-occupied. This allows the stored water temperature to
be raised to a new safe level in one operation and then the heating plant shut down again
rather than have a large number of small heat inputs to maintain the non occupied setting
which might result in the main plant running continuously at a low level. If FRSE is set
to zero the controller will control to the non-occupied setpoint as before.
The DHW Controller can now be made aware of the Frost
protection status of the Boiler (or other heat source). If the Zone Controller alarms are
enabled (ALRM>0) then the Controller will receive FRST alarms from the Boiler. If the
Boiler is in Frost protect this is communicated to the DHW controller which will open any
actuators to 50% (see also config variable FRPT) . The DHW controller remains in
non-occupied so this mode can be distinguished from Fabric Protection.
The code which supports configurable plots has been
included in this issue of the DHW Controller. This works the same as for the
AHU controller. This has meant that the sensor order has been changed so that
the first two sensors have plots
S1 HW T DHW Temperature
S2 DMND Control output 0 to +100 heating
S3 HWSP Current setpoint
The DHW controller supports sensor fail SENF alarm,
this is raised if the DHW sensor fails. The STOP alarm is also supported provided the
Alarm mode is set correctly. See config variable list.
Alarm mode and Alarm State config variables have been
added to the config variable list.
The DHW controller like a Zone Controller uses the AUTO and OVERRIDE switches to control the Occupancy state which prevents MANUAL control of the outputs from Doorway. A new control mode has been added which allows Doorway to select MANUAL, this is activated by setting switch 5 HAND. The forces the controller to manual mode and the output is defined by the value on the config variable MANL. On this controller only 0 to 100% has significance because the DHW controller only has heating. The process of selecting HAND and setting the manual level can be associated on the same point by using the following Doorway syntax.
[Z1]W5(S)/auto/hand/12/10/C18(V) assumes the controller is Zone 1
clicking on the point allows selection of hand or auto and also the means to set C18 which is the manual level required.
A new config variable XHRS allows the 'out of hours'
run time to be configured. This parameter can be set from 0.0 hours to 8.0 hours with a
resolution of a tenth of an hour. The default for DHW controller is 2.0 hours.
When controlling Calorifiers which have a large
thermal reservoir it might be desirable to control using ON/OFF thermostatic control, this
can be selected by setting config variable STAT to 1. In this case the output will switch
on if the temperature is less than setpoint-UNDH and will switch off when it reaches
setpoint+OVRH.
When slaving times from a master controller it is
sometime useful to vary the DHW times, either earlier or later than those set on the
master. In schools this is often required for cleaners or kitchen staff. The start time
can be adjusted plus or minus 10 hours with a resolution of 6 minutes using AJST.
Similarly the stop time can be adjusted with AJSP.
It is sometimes more appropriate to send a constant temperature demand to the registered Heat Source, this used to be done by default if the Heat Source 1. This may no longer be appropriate if the System Master is a Floor Controller and not a Boiler Controller. A new configuration variable allows the minimum CT setpoint to be defines and also forces the controller to send its demands as a CT setpoint. Note only some Secondary controllers will be able to accept CT setpoints, at present it is only Boilers and Secondary Boilers also note that the default is for the DHW controller to send Heat Demands like other controllers so HTCT will need to be set when DHW is used with a Boiler Controller.
This is defined with a config parameter FRPT and it defines the controllers action when it receives a 'frost alarm' from the boiler controller.
| 0 | no action (default) |
| 1 | heating output to 50% |
| 2 | heating output 50%, run pump (fan) |
The universal output driver is used for this product, the driver characteristics are setup using six driver configuration variables These have been placed in a new 'fixed block' starting at config 150. Currently supported driver types are:-
| type | description |
| 0 | driver disabled, no output |
| 1 | raise/lower valve/damper driver |
| 2 | sequence plus TP |
| 3 | sequence plus fast TP |
| 4 | analogue output |
| 5 | dual raise/lower (uses three relays) |
| 6 | single fan in last relay position |
| 7 | multi-speed fan |
| 8 | heat pump |
For full details on the driver options click
here
The Cooling output is used to drive the immersion heater or any other type of auxiliary heat. The config labels are left the same so that the production setup software does not get confused.
The Fan type parameter FTYP is used to control a pump, the interlocks HDLY and CDLY are used to determine pump on delays or pump run on times for the heating and electric outputs. The config variable OCCO can be set to only allow pump operation during the occupied period.
Example combinations with DHW-DIN-RLY (or
DHW-DIN-TOP)
| description | HTYP | HSTG | CTYP | CSTG | FTYP | FSTG |
| raise/lower heating | 2 | 1 | 0 | 0 | 0 | 0 |
| raise/lower heating plus pump | 1 | 2 | 0 | 0 | 6 | 1 |
| TP heat and TP immersion plus pump | 2 | 1 | 2 | 1 | 6 | 1 |
| three stage heating | 2 | 3 | 0 | 0 | 0 | 0 |
| Slow TP for valve heating Fast TP for immersion plus pump |
2 | 1 | 3 | 1 | 6 | 1 |
| Fast TP heating, two channels in sequence plus pump | 3 | 2 | 0 | 0 | 6 | 1 |
Will support registration of up to a total of 8
Actuators, Actuator Drivers or Pump ChangeOvers just like a regular Zone.
Controllers are addressed with [Zn] where n is the
Zone number 1-200.
Sub modules are addressed as follows
Actuators [Z1Am] m=1 to 8
Item codes follow the normal conventions