Table of Contents
Two-stage Source (v2.0)
Full Name
Lib.Mervis.v2_0.TwoStageSource
Description
Block used for controlling the performance of a source (primarily a boiler with a modulated burner and a circulation pump).
Required Project References
- Lib.Mervis
Usage in ST
program test
var
twoStageBoiler: lib.mervis.v2_0.TwoStageSource;
end_var
twoStageBoiler();
end_program
Description of Inputs and Outputs
| Inputs | Name | Data Type | Retain | Required Connection | Meaning |
| OperatingMode | Lib.Mervis.v1_0.OperatingModeType | Yes | No | Source operating mode | |
| PumpOperatingMode | Lib.Mervis.v1_0.OperatingModeType | Yes | No | Circulation pump operating mode | |
| ManualPower | real | Yes | No | Source power in manual mode | |
| Output | real | No | Yes | Controlled variable | |
| Demand | Lib.Mervis.v2_0.StageControlType | No | Yes | Combined demand from the cascade controller | |
| Feedback | bool | No | No | Feedback signal of source operation | |
| Failure | bool | No | No | Feedback signal of source failure | |
| PumpFeedback | bool | No | No | Feedback signal of circulation pump operation | |
| PumpFailure | bool | No | No | Feedback signal of circulation pump failure | |
| ResetRuntime | bool | No | No | Reset runtime hours | |
| MinimalOutput | real | No | No | External input for defining the minimum output temperature (if zero, it is not used) | |
| LimitForAttach | real | No | No | Limit value of the criterion for activating the second stage | |
| LimitForDettach | real | No | No | Limit value of the criterion for deactivating the second stage | |
| MaxOutput | real | No | No | Maximum value of the controlled variable, exceeding it is considered a fault | |
| FeedbackTimeout | time | No | No | Interval waiting for active source operation feedback | |
| FailureCountLimit | uint | No | No | Number of consecutive source errors before it is permanently marked as non-functional | |
| FailureDelay | time | No | No | Time after an unsuccessful source start before retrying | |
| MinimalRunTime | time | No | No | Minimum time the source will be kept running | |
| MinimalStopTime | time | No | No | Minimum time before the source is restarted | |
| KeepCommandWhileFailure | bool | No | No | Determines whether the operation command remains active even in case of a fault | |
| UseLocalOutput | bool | No | No | Determines whether the control uses the common output or its own (= true) | |
| PumpRunDown | time | No | No | Run-down time of the circulation pump after the source is removed from the cascade | |
| PumpFeedbackTimeout | time | No | No | Interval waiting for active circulation pump operation feedback | |
| PumpNotRunAlarmPriority | AlarmPriorityType | No | No | Priority of the circulation pump not running fault | |
| PumpFailureAlarmPriority | AlarmPriorityType | No | No | Priority of the circulation pump failure |
| Outputs | Name | Data Type | Meaning |
| State | Lib.Mervis.v2_0.StageInfoType | Combined source state to the cascade controller | |
| Command1 | bool | Command for operating the first stage | |
| Command2 | bool | Command for operating the second stage | |
| PumpCommand | bool | Command for the circulation pump | |
| RunTimeInHours | udint | Source runtime in whole hours | |
| PumpCompositeState | udint | Bit field describing the state of the circulation pump (see SwitcherBlock v2.0) |
| Blocks | Name | Data Type | Meaning | ||||||||||||||||||||
| PumpControl | Lib.Mervis.v2_0.SwitcherBlock | Control of the circulation pump | |||||||||||||||||||||
| Alarms | Lib.Mervis.v1_0.AlarmsExtender4 | Alarm function block | Alarm Input | Priority | Meaning | Alarm1 | 33 | Source failure | Alarm2 | - | Not used | Alarm3 | 33 | Exceeding maximum output value | Alarm4 | - | Not used | ||||||
Detailed Function Description
TODO