ACTxW4c1

6th February 2001

New product first issue

General

The Window Controller controls opening windows and dampers in Naturally Ventilated buildings. The controller registers as an Actuator controller and can be used with AHU, Secondary Cooling, Zone controllers as the master module.

The window opening can be modified by Wind Speed and Direction as measured by a SeaChange Wind Interface module. Further settings allow the window opening to be limited by the Outside temperature.

When used on 3T hardware only one window actuator can be controlled per module with the raise lower interface, if Analogue output hardware is used then two diametrically opposed windows can be controlled from the one actuator.

Control functions

The module receives cooling demands and occupancy from it's master module, while occupied the module will open the window as defined by the Minimum Fresh Air setting MNFA, unless the cooling demand is greater in which case the window will open an ammount equal to the cooling demand. The maximum window opening can be overridden based on Wind Speed, Direction and Outside temperature as configured by the following settings.

Wind Speed Override

Two configuration parameters define the Wind speed operation.

• MNWS Minimum Wind Speed defines the lower wind speed limit below which no wind override occurs
• MXWS Maximum Wind Speed defines the upper wind speed limit at which the Window will be overriden closed

Between these limits the maximum window opening will be progressivly changed from 100% to 0%. The incoming demand signal will be rescaled to match the modified maximum opening, so if the demand was 50% and the Wind Speed was dictating a maximum opening of 60% then the window would be opened 30% (50% of 60%).

Setting both parameters to zero will disable this feature.

Wind Direction Override

Three parameters define the Wind Direction override.

• NOWS No Wind Speed, for wind speeds below this value the direction of the wind is ignored
• WNWD Window Direction, this is the compass bearing measured from inside the building looking perpendicularly out of the window.

• DDEV Direction Deviation. The window will be allowed to open to maximum when the wind is from the direction diametrically opposed to the Window Direction. Wind direction is always specified as the direction which the wind is coming from, so with a northerly wind, a south facing window is on the lee side of the bulding and can be opened. The Direction Deviation parameter specifies how much the wind direction needs to change from the downwind condition before the window needs to be shut. The diagram plots maximum window opening against wind direction deviation for a number of settings of DDEV Direction Deviation. It can be seen from this that if the DDEV is greater than 180 the window can be allowed to open a small amount even when the wind is blowing directly onto it.
• 

Setting the DDEV Direction Deviation parameter to zero will disable the Wind Direction Override.

Outside Temperature Override

This override prevents or limits window opening when the outside temperature is below or between preset temperature limits.

OUTT Outside Top limit, if the Outside temperature falls below this setting then the Maximum window opening will be progressivly reduced until

OUTS Outside Shut limit is reached where the Maximum window opening will be at 0%

If both these parameters are set to zero then this feature will be disabled.

Calculation Mode

The factors calculated for each of the Window opening restrictions described above may be combined in one of two ways as defined by the CALC configuration variable.

CALC=0 Factors Multiplied

The indivudual factors from each calculation are multiplied together so for example if the Wind Speed factor is 80%, the Wind Direction Factor 50% and the Outside Temperature factor is 60% then the resulting re-scale applied to the window opening would be 0.8 *0.5 *0.6* 100 or 24%, in this case 100% cooling demand would open the window by just 24%

CALC=1 Minimum

In this case the lowest factor would be used to rescale the demand, with the same figures as above the Wind Direction factor of 50% is the lowest so 100% cooling demand would be re-scaled to 50%.

Each of the individual factors can be viewed on the sensor page, OSFR Outside Factor, WSFR Wind Speed Factor and WDFR Wind Direction Factor. The sensor FACT Resultant Factor displays the result of the combining calculation.

Manual Mode

This now follows the system first used on the Fan Coil controllers and recently introduced on AHU controllers. Holding down override button selects manual, status led flashes, initially this just sets 'occupied' and the controller will control to the occupied setpoint if a sensor is connected. The next press on the override button selects manual heating, the temperature led shows red, if the controller has a pot fitted this can be used to set the output level, otherwise full heating is selected. A further press on override gives manual cooling, temperature led shows yellow, again the pot if fitted controls the level of the output. A further press cancels manual.

From Doorway, manual can be selected using the hand/auto syntax see universal manual for more details. SeaChange Insite has full override feature which are supported in the issue.

External Source for Occupation State

The Actuator Controller now supports input mode which allows an external input to be used to provide an occupancy signal or an Alarm. The VFC is wired into input a (centre pair of terminals) and the configuration parameter INMD is set to between 1 and 5, see configuration table.

When input mode INMD 1 (AND function) is used the external input can be used to 'enable' normal control, when the input is shorted the controller responds to the heat demands received from other controllers, when the input is open circuit the controller shuts down. This could be linked to a rain signal or manual window close switch.

Input mode 2 (OR function) or 3 (external only) is designed to be used in conjunction with Control Mode CMDE 2. When the external input is TRUE a dummy demand signal of 100% is created for all configured drivers. This allows outputs to be enabled based only on the presence of the external VFC. Use of these INMD's in other control modes is not recommended.

Status Monitoring

The two inputs on the controller can be utilised for Status monitoring if they are not being used for Temperature Control or Occupancy control (see above). The State of the input can be read on Configuration parameter C180 for input a and C181 for input b. If using input b for monitoring make sure that the control loops are disabled by setting Control Mode CMDE to 0 or 2.

Hardware

Driver Options

This controller uses the Universal Output driver code which allows a large variety of relay and analogue output options to be selected using configuration parameters. Instead of setting a single TYPE parameter to define the driver setup six parameters have been made available so that new combinations of output are possible.

This table summarises the standard sales options for ACT-DIN-3T hardware

Step Driver (type 9)

A new driver type is now available which allows from 1 to 4 relays to be activated in response to the driver demand. This driver has been developed to allow multiple sets of small plant ( pumps fans etc) to be energised. Each step is enabled at approximately one second intervals so that the starter loads are spread over time. This driver provides 1 to 4 steps with no time proportioning action between steps and so might also be used for other staged plant.

Driver Input Rescaling

When using actuators in a driver mode, no temperature sensor fitted, in conjunction with AHU Controllers, the actuator can be made to operate over a restricted part of the overall heat or cool demand range. For example a water battery might be suplimented with electric heater battery, the water battery could be controlled using the AHU raise lower outputs for heating demands 0 to 50% say and an actuator controller could be used to drive the electric battery using Fast TP and solid state relays from 50% to 100%. The rescaling is acheived by setting configuration parameters Heat Rescale MaXimum HRMX, and Heat Rescale MiNimum HRMN for heating and CRMX, CRMN for cooling. These parameter are found in the same block as the driver setting C150-C159.

Plots

There are two plots setup as normal on the first two 'sensors'.

Plot 1 Supply air temperature
Plot 2 Heat/cool output -100 to +100 (negative for cooling)

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.

The plots can be reallocated to other 'sensors' or calculated parameters within the controller using config parameters.

Alarms

The Actuator controller supports STOP alarm, and the receipt of the Frost protect alarm from the boiler.

Alarm mode and Alarm State config variables have been added to the config variable list.

Alarm mode 0 alarms ignored
1 alarms reported no other action
2 control output set to zero on STOP alarm

Doorway codes

Actuator Controllers are addressed with [ZnAm] where n is the Zone number 1-200, and m is the actuator number on that zone.

Item codes follow the normal conventions

Configuration Parameters see Config Tables

network variable list