The following tables describe the attributes and inputs and outputs used by the Global Sequencer module.
| Name | Description | Mode 1 |
|---|---|---|
| Break Limit | This array of float values represents the limits at which each successive stage is deactivated. If Proactive is True, the first limit applies to the second stage, the second limit applies to the third stage, and so on. Each successive value must be greater than the previous break limit and also less than its corresponding make limit. The size of this array is set to Number of Outputs (or Number of Outputs – 1 if Proactive is True) at configuration time. These values are calculated using Device Capacity when Calculate Make-Break Limits is True. | SP, SQ, ER, ES |
| Calculate Make-Break Limits |
When this value is True, the Make/Break Limit values are calculated using the Device Capacity and Differential values. When this value is False, the Make/Break Limit values must be set by the user.
Note: When using this option, varying capacities could yield unexpected results depending on the selected staging mode.
|
SP, SQ, ER, ES |
| Device Capacity | This array of analog values represents the capacity of each device output. These values are used to calculate the Make Limit values when Calculate Make-Break Limits is True. When Calculate Make-Break Limits is False, these are ignored and the Make Limits must be set by the user. | SP, SQ, ER, BC, ES |
| Device First Of | This value specifies how many devices are in the group where this device is the first of the group. This device and the following (value – 1) devices are grouped together for control. The Device First Of property for the dependent devices of this group are ignored. | SP, SQ, ER, ES |
| Differential | This value is used to calculate the Break Limit values when Calculate Make-Break limits is true. When Calculate Make-Break Limits is False, these are ignored and the Break Limits must be set by the user. | SP, SQ, ER, BC, ES |
| Equal Runtime Within Sets |
This Boolean value indicates the effect of runtime on items within Sets. When this property is True, the devices within a set are controlled to equal runtime. If it is False, the first device is the compressor, and subsequent device are unloaders, and runtime on unloaders are ignored. When the property is True, the runtime of the set is the sum of all items within the set. When it is False, the runtime of the set is the runtime of the first device. This property is only evaluated when the Mode is set to Equal Runtime mode. If both Equal Runtime Within Sets and Invert Stages in Sets are set to True, the sequencer only obeys the Invert States in Sets property. |
ER |
| Instant Shutdown Delay | This delay value is used by the Instant Shutdown feature to control the rate at which the devices turn off. | SP, SQ, ER, BC, ES |
| Inter-stage Delay On Rotate | This Boolean value indicates whether or not Minimum On/Off and Inter-stage On and Off timers must be respected before a rotation can occur (from either the Rotate command or the Rotate Now input). When the property is False, the primitive ignores any of these timers and proceeds with the rotation. When this property is True, the primitive ignores the Rotate Now Delay, but does respect it when the property is False.
This attribute is available when you select Inter-stage. |
ER, BC, ES |
| Inter-stage Timing Method | This value indicates whether Inter-stage timing or stabilize timing is used. Inter-stage timing starts when a stage change occurs and prevents another stage change from occurring until it has expired. Stabilize timing starts when the Input exceeds a make limit or drops below a break limit and prevents the stage change from occurring until the timer has expired. | SP, SQ, ER, BC, ES |
| Invert Stages in Sets | This Boolean value indicates the action of devices within a group as specified in Device First Of. If this input is True, when the first device of a group is turned on, all the devices are turned on and the second and subsequent devices of the group are turned off sequentially as the load increases. If this input is False, when the first device of the group is turned on, the remaining devices of the group turn on sequentially as the load increases. This property cannot be used when Equal Runtime Within Sets is True and the Mode is set to Equal Runtime mode. If both Equal Runtime Within Sets and Invert Stages in Sets are set to True, the sequencer only obeys the Invert Stages in Sets property.
This attribute is available when Oil Pump on Device 1 is False. |
SP, SQ, ER, ES |
| Make Limit | This array of analog values represents the limits at which each successive stage is to be activated. If Proactive is True, the first limit applies to the second stage, the second limit applies to the third stage, and so on. Each successive value must be greater than the previous make limit and also greater than its corresponding break limit. The size of this array is set to Number of Outputs (or Number of Outputs – 1 if Proactive is True) at configuration time. These values are calculated using Device Capacity when Calculate Make-Break Limits is True. | SP, SQ, ER, ES |
| Mode | Value indicates the operating mode of the sequencer: SP = Step, SQ = Sequential, ER = Equal Runtime, BC = Binary Code, ES = Equal Startup. | SP, SQ, ER, BC, ES |
| Number Of Outputs | This is the number of binary outputs to be controlled by this sequencer. | SP, SQ, ER, BC, ES |
| Oil Pump Off Delay | This delay value is used by the Oil Pump feature to determine how long to run the oil after stopping the last compressor. This is an optional item typically used with chillers.
This attribute is available when Oil Pump on Device 1 is False. |
SP, SQ, ER, ES |
| Oil Pump On Delay | This delay value is used by the Oil Pump feature to determine how long to run the oil before starting a compressor. This is an optional item typically used with chillers.
This attribute is available when Oil Pump on Device 1 is False. |
SP, SQ, ER, ES |
| Oil Pump On Device 1 | This property indicates whether the single oil pump runs with the compressor attached to Device 1 Out or has its own motor. This is an optional item typically used with chillers. | SP, SQ, ER, ES |
| Proactive |
This value indicates the mode of operation for the sequencer. When this value is set to False, the lead output is activated when the input reaches the first make limit. When this attribute True, the lead output is placed in a continuously activated state (provided Instant Shutdown is set to False) and as such, the second stage is actually activated when Input reaches the first make limit. Note: Proactive has no meaning when in Binary Code Mode.
|
SP, SQ, ER, ES |
| Pump Down Available | This property indicates whether a solenoid valve is connected to the Solenoid Valve output and a Low Pressure input is connected to the low pressure input. When this input is True, the stager provides a pump down using the low pressure input and solenoid valve output. This is an optional item typically used with chillers. | SP, SQ, ER, ES |
| Rotate Now Delay |
This delay value is used by the Rotate Now feature to turn new devices on before turning previously running devices off. This attribute is available when Inter-stage Delay On Rotate is False. |
ER, BC, ES |
| Sequence Order | This integer array contains the activation/deactivation order of the sequencer as determined by the Lead Rotation. In the case where the sequencing order is Device 3 Output, Device 4 Output, Device 1 Output, and Device 2 Output for a four stage Sequencer, the contents of this array are {3, 4, 1, 2}. | SP, SQ, ER, ES |
| Time Remaining Update Interval | This property controls how fast the Time Remaining outputs update. If this value is zero, the Time Remaining output does not update. This is used to conserve system bandwidth if no timer diagnostics information is needed. | SP, SQ, ER, BC, ES |
| Name | Description | Mode 2 |
|---|---|---|
| Current Stage | This value indicates the number of the active outputs of the sequencer. | SP, SQ, ER, BC, ES |
| Device n Enable | These Boolean values establish the enable status of the sequencer device outputs. A value of False takes the associated device out of service. Only the enables for the number of outputs are shown. The primitive is created with n individual Device n Enable inputs based on Number of Outputs. | SP, SQ, ER, BC, ES |
| Device n Out | These Enum values contain the output value for the corresponding device. The primitive is created with n individual Device n Output inputs based on Number of Outputs. | SP, SQ, ER, BC, ES |
| Device n Runtime | These float values represent the runtime of each device. This value establishes the order by which the device outputs are activated. Only the runtimes for the number of outputs are shown. The primitive is created with n individual Device n Runtime inputs based on Number of Outputs. | ER, ES |
| Device n Start Count | These float values represent the number of starts of each device. This value establishes the order by which the device outputs are activated. Only the number of starts for the number of outputs are shown. The primitive is created with n individual Device n Start Counts inputs based on Number of Outputs.
See |
ER, ES |
| First Set On Delay | This float attribute provides the time to wait when the first stage up is started before starting the next set. | SP, SQ, ER, BC, ES |
| Force Downstage | This attribute is rising edge activated. It retains a value of True until it is written back to False. Writing this attribute to True causes the Sequencer to decrease the number of stages active. The sequencer waits for timers to expire. For example, if a On Delay timer is active on the stage to stop, then it waits for that timer to expire. | SP, SQ, ER, BC, ES |
| Force Upstage | This attribute is rising edge activated. It retains a value of True until it is written back to False. Writing this attribute to True causes the Sequencer to increase the number of stages active. The sequencer waits for timers to expire. For example, if a Off Delay timer is active on the stage to start, then it waits for that timer to expire. | SP, SQ, ER, BC, ES |
| Input | This float value is the control signal input to this primitive. It is compared against the make and break limits to determine how many outputs to activate. Typically, this input is scaled 0 – 100 %, but it can be scaled in Power Units (Tons/kW) of the Plant if that is preferred. | SP, SQ, ER, BC, ES |
| Instant Shutdown | This Boolean value forces all outputs inactive when it is True. When it is False, the primitive monitors the input and stages the outputs. When this value transitions from False to True, all of the outputs are deactivated in sequence with a delay of Instant Shutdown Delay between steps (ignoring any Minimum On Timers, Inter-stage Timers and Stabilize Timers). If a step down would normally start another device, the device that would be started is not turned on. | SP, SQ, ER, BC, ES |
| Interstage Off Delay n | This attribute defines the minimum time interval that must elapse between the sequential deactivation of multiple Sequencer stages unless the Instant Shutdown value is True or the primitive is disabled. The associated timer starts immediately after a stage down event.
This attribute is available when you select Inter-stage. |
SP, SQ, ER, BC, ES |
| Interstage On Delay n | This attribute defines the minimum time interval that must elapse between the sequential activation of multiple Sequencer stages. The associated timer starts immediately after a stage up event.
This attribute is available when you select Inter-stage. |
SP, SQ, ER, BC, ES |
| Interstage Time Remaining | This float value provides the time remaining until a stage up or down can occur. These timers start immediately after a change in stage.
This attribute is available when you select Inter-stage. |
SP, SQ, ER, BC, ES |
| Low Pressure | This input provides the indication necessary to control the Solenoid Valve Out for pump down. This is an optional item typically used with chillers.
This attribute is available when Pump Down Available is True. |
SP, SQ, ER, ES |
| Min Off Time n | This is the minimum time that an output must remain off before it can be reactivated to an on condition following deactivation. As such, a separate timer is established for each device output upon being deactivated. Until the time interval expires, the output is blocked from being reactivated unless Rotate Now has transitioned from False to True. | SP, SQ, ER, BC, ES |
| Min Off Time n Remaining | This float value provides of the time remaining until the device can be turned on. | SP, SQ, ER, BC, ES |
| Min On Time n | This is the minimum time interval that an output must remain on before it can be deactivated to an off condition following activation. As such, a separate timer is established for each device output upon being activated. Until the time interval expires, the output is blocked from being deactivated unless the Instant Shutdown value is True, the primitive is disabled, or Rotate Now has transitioned from False to True. | SP, SQ, ER, BC, ES |
| Min On Time n Remaining | This float value provides of the time remaining until the device can be turned off. | SP, SQ, ER, BC, ES |
| Next Device to Start | This float value identifies the next device that starts when the sequencer stages up. When there are no longer any devices to stage up, the value is 0. | SP, SQ, ER, BC, ES |
| Next Device to Stop | This float value identifies the next device that stops when the sequencer stages down. When there are no longer any devices to stage down, the value is 0. | SP, SQ, ER, BC, ES |
| Oil Pump Out | This output is used to control a single oil pump associated with all of the compressors. This is an optional item typically used with chillers. | SP, SQ, ER, ES |
| Operating State | This enum value identifies the operational state of the sequencer at any given point in time, including Idle, Deactivated - Instant Shutdown, Shutdown In - Process, Staging Up -Interstage On Delay, Staging Up -Minimum Off Delay, Staging Down -Interstage Off Delay, Staging Down - Minimum On Delay, Insufficient Capacity. | SP, SQ, ER, BC, ES |
| Remaining | This output is the capacity requested on the Input that is not met by the devices that are on. Remaining = Input – SUM(On Devices) | SP, SQ, ER, BC, ES |
| Rotate Now | This attribute is rising edge activated. It retains a value of True until it is written back to False. Writing this attribute to True causes an immediate rotation based on the current ranks. As this rotation occurs, devices that are transitioning from off to on are started and after an adjustable delay, the devices transitioning from on to off are stopped. | ER, BC, ES |
| Solenoid Valve Out | This output is used to control a solenoid valve for pump down of the compressors. This is an optional item typically used with chillers.
This attribute is available when Pump Down Available is True. |
SP, SQ, ER, ES |
| Stabilize Off Delay n | This attribute defines the minimum time interval that must elapse between the sequential deactivation of multiple Sequencer stages unless the Instant Shutdown value is True or the primitive is disabled. The associated timer starts after the Input drops below a break limit.
This attribute is available when you select Stabilize. |
SP, SQ, ER, BC, ES |
| Stabilize On Delay n | This attribute defines the minimum time interval that must elapse between the sequential activation of multiple Sequencer stages. The associated timer starts after the Input exceeds a make limit.
This attribute is available when you select Stabilize. |
SP, SQ, ER, BC, ES |
| Stabilize Time Remaining | This float value provides the time remaining until a stage up or down can occur. These timers start when the input exceeds a make limit or drops below a break limit.
This attribute is available when you select Stabilize. |
SP, SQ, ER, BC, ES |
| Vernier | This analog output of 0 to 100 indicates the required percentage of the currently modulated device required to meet the required capacity. The Remaining output is rescaled from 0 to 100%. | SP, SQ, ER, BC, ES |
1 SP = Step, SQ = Sequential, ER = Equal Runtime, BC = Binary Code, ES = Equal Startup
2 SP = Step, SQ = Sequential, ER = Equal Runtime, BC = Binary Code, ES = Equal Startup