Main Features Automatic Control of Atrium Windows, Roof Lights or Dampers in Naturally Ventilated buildings Control based on Internal Cooling Demands and Air Quality Controls Extract Dampers and Extract Fans CO2 / Air Quality Override Facility Night Purge Interlock with AHU Plants Works with or without Local Temperature Feedback

Summary Features

General

This is a specialist version of the standard Actuator Controller. In addition to the standard features of an actuator sub module, the actuator submodule provides special control options for controlling extract dampers, extract fans, CO2 and air quality control and night purge interlock with AHU plants.

Configuration parameters can be set to allow operation to match the plant control requirements. A full table of configuration and monitoring parameters is detailed later in this data sheet.

A table of available product versions is shown on the last page.

Operation

Actuator Submodules are driven by Control Demand signals from the module that they are registered to.

Different Driver Types may be selected to give Time-based control or Demand-based control in various combinations.

Air Quality Control

The temperature control, or the Cooling demand signal into the module, can be overridden by an Air Quality signal. This signal will create a minimum output level for the cooling output. As Air Quality deteriorates, the Fresh Air requirement will increase, and the minimum output will increase until it reaches the full fresh air position, 100% cooling.

This means that Air Quality Control will override Temperature Control, which is the requirement for spaces which have variable numbers of occupants and heavy contamination of the air (e.g. cigarette smoke). Conversely, as Air Quality improves, the minimum output will reduce allowing the temperature control to be reinstated..

The points at which the Air Quality signal starts to override the Temperature Control may be set on 2 parameters MNAQ and MXAQ.

CO2 Control

CO2 is an accurate measure of the Occupancy rate of a building; it is particularly useful in spaces with variable occupancy e.g. auditoria, meeting rooms. A CO2 sensor may be substituted for the Air Quality sensor, and the controller will now increase the Fresh air quantity as CO2 levels rise.

Fan Speed Control Based on Air Quality

You can use the actuator sub module on other applications where there is a requirement to alter the fan speed based on the measured air quality.  Using an ACT/DIN/AIRQ/AOP/821 AIRQ actuator sub module, connect a suitable air quality sensor to terminal 3-4.  Connect a suitable resistor to the controller to simulate 10C and set the setpoint range for the cooling to 18-22C to ensure the cooling loop is kept at 0%.  This will ensure the air quality signal will be the only demand fed to the cooling output on the actuator sub module (i.e. the cooling demand on the zone controller has no influence on the operation of the actuator sub module).  Set parameter MIND to zero to ensure the actuator is enabled when the associated zone controller is in occupancy.

Note- the air quality sensor must be fed from its own separate supply as the 0-10V DC input terminal on the actuator sub module is non-isolated.  Therefore you will need to use a separate transformer for the sensor.  If the sensor is mains-powered, ensure that its output is isolated.

Night Purge

If the Actuator controller is being used to control extract dampers and fans it might be necessary to activate these devices if one or more AHU controllers in the building are in Night Purge mode. The Actuator can be linked to one or more (max 8) AHU controllers for Night Purge operation.

Office Churn

Office layouts often change during the lifetime of a building; sometimes this “churn” results in changes to the services which feed each zone. Actuator Submodules cope well with additional Zones, or Zone Controllers having to work with different zone valves as offices “churn” over time because the link between a Zone Controller and its Actuator Submodule may be deleted and re-instated easily, see Registration section.

Output Options

Different Output Driver types can be used for different types of valve; Raise/Lower, Time Proportioning and Staged Drivers are available. The accompanying pump or fan can be switched using the Occupation Switch output C.

Triac outputs can be used for Fast Time Proportioning, allowing low cost proportional control of electric heating loads using external Solid State Relays.

An Analogue Output variant can control a 0 -10Vdc valve and switched loads such as a fan or pump via an external relay module.

Description of Features

Demand Control

The Actuator Submodule has no internal Occupation Time Schedules. Its operation is determined only by a Control Demand signal from the parent module it has been registered to.

The Control Demand interconnect signal from the parent module carries both the control loop demand output level and the parent module occupancy state.

Temperature and Air Quality Inputs

The control temperature sensor is connected to input ‘temp b’ on terminals 5 and 6. The input ‘temp a’ on terminals 3 and 4 can be used for a 0-10v Air Quality Sensor.

Air Quality Control

To activate the Air Quality override the parameter MXAQ must be set to a non zero value. The Air Quality signal is scaled 0 to 100% with 100% being the worst Air Quality. The parameter MNAQ defines the Air Quality value at which the output will begin to be effected, MXAQ defines the Air Quality value at which the cooling output will be overriden 100%. For example if MNAQ=25, MXAQ=75; while the Air Quality signal remains below 25% it will have no effect the Actuator will follow the cooling demand signals, as the Air Quality signal rises above 25% the cooling output will be subject to a minimum output in proportion to the Air Quality signal, when the Air Quality reaches 75% the override will be 100%.  Use ACT/DIN/AIRQ/AOP/821 analogue actuator submodule for cooling cooling control with air quality override.

Temperature Control

Actuator Submodules will work with or without local temperature feedback.  If no optional temperature sensor is fitted, the Actuator Submodule will interpret the Control Demand from its parent module (e.g. a Zone Controller) as a proportional output signal (e.g. a Valve Position). This is called Open-Loop control.

If an optional temperature sensor is fitted, the Actuator Submodule will automatically convert the Control Demand signal into a setpoint (e.g. Desired Supply Air Temperature) and control at the Actuator Submodule becomes Closed-Loop. The overall control scheme becomes Cascade Control, with the output from the Zone Controller’s control loop forming the setpoint for
the Actuator Submodule.

Operation with sensor fitted

The local temperature setpoints used by the Actuator Submodule may be set by the parameters MINH and MAXH for the heating setpoint (scaling from 0% to +100% demand), and MAXC and MINC for the cooling setpoint (scaling from 0% to -100% demand).

Advanced feature:The demand range over which the setpoint is scaled can be modified using the driver rescale parameters, this is useful when there are multiple sources of heat which need to be scheduled across the demand range. For example if the controller is controlling undefloor heating and there is also heat supplied by a Fan Coil heater the underfloor can be activated for the first 50% of demand by setting HRMN=0:HRMX = 50 the setpoint will then change from MINH at 0% demand to MAXH at 50% demand. The Fan Coil would be controlled on another actuator with scaling parameters set to HRMN=50:HRMX=100. If the controller is changed to open loop either by removing the sensor or changing CMDE then the rescale is applied to the driver demands.

The parameter CMDE = 1 enables a sensor connected to ‘input b’ to become the primary control sensor. The setting of CMDE = 2 can be used to change the control action to on/off control, where the heating or cooling output from the Actuator Submodule will be 100% when the controller is Occupied. In this mode, the sensor inputs are used for monitoring or alarm input only.

Operation with no sensor fitted

If no sensor is fitted (or the sensor is disconnected) the Controller will effectively bypass its control loop, and the Zone Demand will be used to drive the valve directly (thus if the Zone Demand is 70%, the valve will be driven to 70% open). This is called Open Loop control.

Sometimes, Open Loop operation is required but the sensor is needed for monitoring (for instance, if the Actuator Submodule was being used to enable a device with its own temperature controls, then the Controller’s own control loop would need to be disabled). In these cases, setting parameter CMDE = 0 will disable the control loop, allowing Open Loop operation, whilst leaving the sensor connected for monitoring purposes.

Pump Time Interlock Settings

The pump or fan can also be set to delay its start after the heating/cooling outputs have started, or to run on after they have shut down, using the configuration
parameters HDLY and CDLY. A negative value will start the pump the defined number of minutes after the heating/cooling drivers have been enabled; a positive value will cause the pump to run on after the heating/cooling drivers shut down.

Multiple Staged Fan Speed Control

Where delays are required when switching between stages of fan speed, the parameter FPRD can be set to a minimum time between switching stages

Frost Protection

The Actuator Submodule can be made aware of the Frost protection status of the Boiler controller. If the Boiler controller is in Frost Protect this is communicated to the Actuator Submodule which will open the heating valve to 50% (to primary coils and bypass) and run the pump if desired, as set by the parameter FRPT.

Two pipe Heat/Cool systems

The Actutor Submodule can control a valve which is used for both heating and cooling as part of a 'TWO PIPE' system. The temperature of the circulating medium, usually water, is received as the flow temperature from a Heat Pump controller or secondary controller(version 4d or later). The parameter TWOP is set to 1 and the controller will only allow heating if the flow temperature is above 20degC and only allow cooling if it is below 20degC. Since the same valve is used for both heating and cooling then the driver needs to be set to redirect the cooling demands to the heating driver, set the same driver type for both heating and cooling but only set the stages for the heating driver.

Alarm Handling

The Actuator Submodule may be set to ignore alarm conditions, report them to a SeaChange Doorway Supervisor (either locally connected to the system, or via an autodialling modem), or to both report alarms and take some control action. The ALRM parameter is used to select the desired Alarm Mode. The Actuator Submodule generates an alarm if the sensor fails and also if the external alarm input is used. The sense of the alarm input can be set by parameter ALST.

The Actuator Submodule may be set to respond to the STOP System Stop Alarm which is generated by another Controller; this can be used to shut down the entire control system, or parts of it, if a particularly critical event occurs. See Boiler Controller datasheets B1 or B2 for more details about the System Stop Alarm.

Alarm codes as they appear at Doorway Supervisor and InSite tool:

Local Indication of Alarms

Alarms are indicated by red flashing of the Temperature Indicator (Thermometer) LED, if the alarm results in a control action (e.g. shutting down the pump/valve). If ALRM is set to 0 (ignore alarms) or 1 (report alarms to supervisor only) then no control action will be taken, and the thermometer LED will not flash.

Commissioning

Setup Mode : Timing Characteristics of Output Channels

It is possible to set the stroke time (for Raise/ Lower type Actuators) and the minimum on/off time (for Time Proportion type Actuators) using pushbuttons.

Raise/Lower Types - Setting Stroke Time

1. Hold down Select until Temp lamp flashes
   Temperature indicator will flash red at one second intervals.
   Release select button; output B will energise to close valve.

2. When valve is closed press Select
   Temperature indicator will flash green and output A will energise to open valve. The controller is now measuring the stroke time.

3. When the valve is open press Select
   Flashing will stop and stroke time is now set and stored in non-volatile memory. This time will be retained until the procedure is repeated.
   

Note: if a Stroke Time of less than 30 secs is set using pushbuttons then the setup process is aborted. Temp indicator flashes amber rapidly for 5 secs indicating an invalid period. This allows checking of wiring without affecting Stroke Time setup. Stroke Times less than 30 secs can be entered manually via Zone Controller or InSite tool.

TP Types - Setting Minimum Time On/Off

1. Hold down Select until Temp lamp flashes
   Temperature indicator will flash green at one second intervals and relay A will energise.
   Release select button.

2. When minimum on/off time has elapsed, press select
   Flashing will stop and this time will be set and stored in non-volatile memory. This time will be retained until the procedure is repeated.
   Note that the full TP period will be 10 times this value.

The times can also be viewed and changed using parameters HPRD (heating) and CPRD (cooling).

Setting Night Purge interlocks (AIRQ Version)

The controller can be interlocked with upto 8 AHU controllers. When any of the interlocked AHUs goes into Night Purge mode then the Actuator will receive 100% cooling demand, if temperature control is being used then the actuator will try to control to the MINC setpoint. otherwise the demand will be passed directly to the cooling driver, the occupancy output will also become enabled.

The parameter C123 ADDI Address Index is set first to define which of the 8 links is being set or monitored, then C124 AHU defines the AHU number. A link can be cleared by setting C124 AHU to zero.

For example assume we need to interlock with AHUs numbers 4, 7 and 10.

1. set C123 ADDI to 1

2. set C124 AHU to 4

3. set C123 ADDI to 2

4. set C124 AHU to 7

5. set C123 ADDI to 3

6. set C124 AHU to 10

The interlocks can be read by selecting 1-8 on C123 ADDI and reading the AHU number on C124.

Manual Override

Allows the outputs to be exercised during commissioning and maintenance activities. Holding the override button pressed until the Status Lamp flashes green will cause the controller to be switched from automatic control to Override Mode. Subsequent pressings of the manual override button will cycle through the available Override modes.

1. Hold down Override until Status lamp flashes
   Controller changes to Override Mode and becomes Occupied, controlling to current Occupied Setpoint.

2. Press Override again
   Controller changes to Manual Mode and output is set to 100% heating.
   Temperature lamp shows red.

3. Press Override again
   Controller changes to Manual Mode and output is set to 100% cooling.
   Temperature lamp shows amber.

4. Press Override again
   Controller cancels Manual Override and reverts to automatic control.

As this feature does not time out, care should be exercised to ensure the module is returned to the automatic mode on completion of the commissioning or maintenance activities.

Occupancy Override can also be achieved via Doorway and InSite; using AUTO and OVRD monitoring parameters. The status lamp indication shows a different sequence.

Override from Off to ON : Status lamp flashes long ON, short Off
Override from ON to Off : Status lamp flashes long Off, short ON
See our ‘Design Guide’ publication for details of the Override features.

Registration

Registration is the simple process by which logical connections are made between Controllers in a SeaChange system; it is done during commissioning and involves pressing buttons on the Controllers in a specific sequence.

For further details of the registration process, see our ‘Design Guide’ publication.

Address Allocation and System Housekeeping

Like all SeaChange Controllers, the Actuator Submodule must be registered with other modules in order to create a working system. During the Registration procedure, the address of each Controller is allocated by the module that contains System Housekeeping. Check that you have an appropriate System Housekeeping Module; see our ‘Design Guide’ publication.

Interconnects

The Actuator Submodule will receive Control Demand signals from other modules to determine when it operates. (see Demand Control).

See our ‘Design Guide’ publication for details of how to create interconnects.

Options and Product Codes

ACT / DIN / AIRQ/AOP /821

SC Controls Ltd

PO Box313
Wadhurst
East Sussex
TN5 6JL

phone 08707 606040
fax 08707 606041
e-mail seachange@sccontrols.co.uk
http:// www.seachange.co.uk