SystemCommand Function Block

The System Command function block is used to override the following wall module to system commands. The wall module sends a command to the AHU or VAV system.

Following are the five system command/states available in the wallmodule:

  1. Off / Heat (Heat only)

  2. Off / Cool (Cool only)

  3. Off / Heat / Cool (No Auto changeover)

  4. Off / Auto / Heat / Cool (Auto changeover)

  5. Off / Auto / Heat / Cool / Emergency Heat (Heat Pump)

It is also possible to override the output from this block by making change in the in field.

Figure 1: SystemCommand Function Block

Figure 2: SystemCommand Property Sheet

Inputs

Input Name

Description

In

To provide the System Command from the controller to the Wall module.

Following are the five system command options available in the wallmodule:

  • Off / Heat (Heat only)

  • Off / Cool (Cool only)

  • Off / Heat / Cool (No Auto changeover)

  • Off / Auto / Heat / Cool (Auto changeover)

  • Off / Auto / Heat / Cool / Emergency Heat (Heat Pump)

Table 1: Inputs of SystemCommand Function

Output

Output Name

Description

Out

To provide the Final System Command from wall module to the controller.

Following are the five system command options available in the wallmodule:

  • Off / Heat (Heat only)

  • Off / Cool (Cool only)

  • Off / Heat / Cool (No Auto changeover)

  • Off / Auto / Heat / Cool (Auto changeover)

  • Off / Auto / Heat / Cool / Emergency Heat (Heat Pump)

Table 2: Output of SystemCommand Function

Parameters

Parameter Name

Description

sylkDevice

This option is used to select the sylk device from the dropdown menu which needs to be linked with the System command.

Default is None

Master Sync Enabled

Master Sync Enabled is true, this property is synchronized between master and slaves in case a master sync operation is performed.

The source device setting is synchronized to a target device during a master sync operation.

If the source device has set the flag to false, then this parameter will not be synchronized to all target devices.

Status

Read-only point. Shows the status of the parameter. (alarm, fault, overridden, disabled, down, stale, null, unackedAlarm).

  • Ok- Indicates that the device is functioning as expected.

  • Alarm- The device has a value in an alarm range as defined by a property in its alarm extension.

  • Fault- this indicates a configuration or license error.

  • Overridden- The functioning of the device has been stopped usually by a hardware override switch.

  • Disabled- Enabled property is set to false.

  • Down- device communication with the parent device as configured in the extension has been lost.

  • Stale- Since the last poll update, the system has not updated the points value within the specified Stale Time of its Tuning Policy.

  • Null- Indicates no status is available.

faultCause

Read-only point. Indicates the reason why a system object (network, device, component, extension, etc.) is not working properly (in fault). This property is empty unless a fault exists.

sendInterval (seconds)

Send interval is the time between the end of a timeout period or completion of a network request, and the next request for data on the network. Default is 60 Seconds.

enableFD

enableFD - Fail Detect is the time until the Sylk controller is notified of a failure on this point.

Yes: If the parameter has not received an update from the IRM network source in the fail detect time, then an alarm is generated, and the present Value is set to Invalid. It is envisioned that most (all) input and input/output parameters will be fail detect so that Sylk controller does not display stale or misleading data.

Note: Fail detect time depends on the update rate configured.

No: False means the object retains the last value that was written to it until a IRM network source changes.

Fail Detect is disabled in the System Command function block and it is not configurable by the user.

Update Rate: The rate at which inputs are sent to the network.

systemCommands

Allows to select the modes of the command from the wall module to the system.

Following are the five valid system command options available:

Off / Heat (Heat only)

Off / Cool (Cool only)

Off / Heat / Cool (No Auto changeover)

Off / Auto / Heat / Cool (Auto changeover)

Off / Auto / Heat / Cool / Emergency Heat (Heat Pump)

Default Value is Off / Heat (Heat only).

defultSystemCommands

Allows to set the default value for the system command options.

Following are the five default system command options available:

  • Off- Controller is off

  • Auto- If the system command is in Auto, then the controller will automatically switch between Cool mode and Heat mode based on the Room temperature sensor value or Supply Air Temperature Sensor

  • Heat- Heated air is supplied network workstation or a node via the central air supply and heated air is supplied to the controlled space.

  • Cool- Cool air is supplied from a network workstation or a node via the central air supply and cooling energy is supplied to the controlled space.

  • Emergency Heat- Emergency Heat is supplied network workstation or a node via the central air supply.

Default Value is Off

systemCommandValues

System command values displays the various command values depending on the valid system commands selected, the respective values are enabled. Invalid values are disabled (depending on the system configuration options selected). Users will be able to switch to Off, Auto, Heat, Cool, Emergency Heat modes.

Off =255

Auto=0

Heat=2

Cool=1

Emergency Heat=3

Emergency Heat, also known as auxiliary heat, is the second stage of heat that your thermostat runs on when the temperature is too cold for your heat pump to extract heat from the outside.

Emergency Heat is triggered when it is 35°F and below outside.

Emergency heat should really be switched on by the users in emergency situations when something happens to the first stage heat source heat pump.

Numeric: 32-Bit Integer value 0, 1, 3, 255. Default: Null.

SetAsNetworksetpoint

This option to connect the System command block with the Network input/set point and the Network output point. If the option is not selected, the System command block can relate to the Network output point, but not with the Network input/ set point.

Note:Set as Network Setpoint is disabled by default. The default value is No. By clicking YES or NO, you can enable or disable this option.

Note:Set as Network Setpoint option is available only for the TR71/TR75/TR120 model.

Out Save

Master Sync Enabled : If you set it to "true" the last output will be set as output for one cycle after the controller restarts. The application can use it to return to the same state before the controller restart.

Out: To enable or disable the Out feature.

Table 3: Parameters of SystemCommand Function

Refer to General Description for general information about IRM N4 Function Blocks.

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