Overview Block Pool

The function block controls a swimming pool: filter pump, backwash, solar absorber, auxiliary heating, pH and chlorine dosing, cover, lighting and frost protection.

The most important part is the filter pump. Each day it runs for a given time that depends on the water temperature: the warmer the water, the longer the pool is filtered. If the PV system delivers surplus power, that daily time is preferably used up while the surplus lasts - whatever is still missing when the time window draws to a close is made up in the evening.

As with all block function blocks, the presence state comes from the Block Presence function block. See also Presence in general.

The matching control element is Block Pool. The switching times, the runtime curve and the setpoints are set there; the function block must be linked to the control element.

Runtime of the filter pump

How long the filter pump should run on a given day is defined as a curve in the control element: one water temperature and the number of hours per support point. Between two support points the function block interpolates linearly; below the first and above the last point their value applies. If no water temperature is linked, the fixed parameter Runtime per day applies.

Filtering only takes place inside the configured time window. At the configured hour of the day change the runtime starts at zero again. If that moment is missed - because the controller has just been restarted, for example - the day change is made up, but only once per day. The runtime of a backwash does not count towards the daily target: no filtering takes place during it.

Without PV operation the runtime is distributed in one of two ways: in one block starting at the beginning of the time window, or spread over sections of equal length. The comparison is always made against the time actually run - a temporary lock is therefore caught up on its own.

Presence: for each presence state - present, absent, holiday - a share of the daily runtime can be defined in percent in the control element. 100 % means unchanged, 50 % half the runtime, 0 % none at all. The pool is therefore filtered less while nobody is at home, without having to change the curve. The share acts on the value from the curve and thus on output TS. By default no state has a setting, and the full runtime applies in every state.

PV surplus and catching up

If the parameter PV surplus is set to Preferably on surplus, the filter pump runs as soon as input PU carries at least the configured Power of filter pump plus the minimum. Whether surplus is a negative or a positive value is defined by the parameter Surplus - the default is negative, the way a grid power measurement delivers it. It is switched off again as soon as the surplus falls below the minimum. Because a running pump consumes its own power from the surplus, the switch-on and switch-off points are far apart - the pump therefore does not react to every passing cloud.

The Control time additionally limits how often the decision is taken, and the Minimum runtime per PV start keeps the pump running for a while after it has started.

Catching up happens without any further configuration: if the time left until the end of the time window is just enough for the missing runtime - plus the Catch-up margin - the pump keeps running regardless of the surplus until the daily target is reached. On a sunny day the target is largely met by the evening, so this forced run only starts after sunset on its own. On an overcast day it moves forward accordingly instead of the pump missing its hours.

With the setting Only on surplus nothing is caught up; the missing time expires at the day change. The default is Off - only the time window with its distribution applies then.

Auxiliary heating

The auxiliary heating is the second heat source of the pool besides the solar absorber: a heat pump, a heat exchanger connected to the building heating or an electric heater. The function block switches it on and off through output NH; it does not control the power - that is up to the device itself.

Heating starts as soon as the water temperature is more than the configured hysteresis below the setpoint, and stops when the setpoint is reached. The setpoint is set in the control element, not in the parameters - it is adjusted during operation, before a pool party for example.

Heating only takes place inside the time window Heating from / to. That allows the heating to be placed in the hours when electricity is cheap or the heat pump is running anyway.

Heating without circulation is not allowed - the heat exchanger would stand still in hot water. The parameter Heating and filter pump defines how the function block handles this: wait until the filter pump runs, or request it. On low water, in winter mode, during a backwash and while the function block is locked the auxiliary heating stays off.

Backwash

The backwash is a sequence of several steps. Before and after every valve change the filter pump stands still for the configured Valve switching time - the valve is never switched while the pump is running:

Pump off → valve to backwash → pump on for the backwash time → pump off → valve to rinse → pump on for the rinse time → pump off → valve back to filtering.

The sequence is triggered when the interval has elapsed at the configured hour, by a filter pressure above the limit (only evaluated while the pump is running), by input RB, by a switching time or by hand in the control element. It is blocked on low water, in winter mode, while the function block is locked and - if configured that way - while the cover is closed.

If low water occurs during the sequence, everything is switched off immediately, the valve is set back to filtering and a fault is reported. A restart of the controller does not continue the sequence either but returns to filtering: after a power failure the valve position is not reliably known.

Protective functions

Low water switches the filter pump off immediately - without any minimum runtime - and with it the solar pump, the auxiliary heating and the dosing. It reports a fault.

Frost protection: if the outside temperature falls below the configured value, the filter pump runs. Frost protection wins against enable, lock, winter mode, time window and minimum times. It does not win against low water: running dry destroys the pump, which weighs heavier than frozen pipes. Without a linked outside temperature there is no frost protection.

Dosing only runs while the filter pump is running and only after it has been running for the configured lead time - before that the measured value is not meaningful. Dosing works in cycles: a dosing time, then a pause during which the agent is distributed in the pool. The Maximum duration per day is a hard limit: once it is reached, no further dosing takes place and a fault is reported.

Solar is protected twice: by the maximum temperature of the water and by that of the collector. Switching on happens one kelvin below the limit, switching off when it is reached.

Inputs

FG
 Enable
 Optional. 0 locks the function block, anything other than 0 enables it. If the input is not linked, the function block counts as enabled - a newly created function block is therefore not locked. Frost protection also runs while the function block is locked.
WT
 Water temperature
 Optional. Basis of the runtime curve, the solar differential control and the auxiliary heating. Not linked: the parameter Runtime per day applies, solar and heating stay off.
AT
 Outside temperature
 Optional. Basis of the frost protection: below the configured value the filter pump runs, above that value plus the hysteresis it stops again. Not linked: no frost protection.
KT
 Collector temperature
 Optional. Temperature of the solar absorber. Not linked: the solar pump stays off - without both temperatures no difference can be formed.
PH
 pH value
 Optional. Reading of the pH probe. Dosing starts as soon as it deviates from the setpoint by more than the configured tolerance. Not linked: no dosing takes place.
RX
 Redox value
 Optional. Reading of the redox probe in mV. Dosing runs while it is more than the tolerance below the setpoint. Not linked: no dosing takes place.
DR
 Filter pressure
 Optional. Pressure gauge at the filter. If the pressure reaches the limit while the filter pump is running, a backwash is started - with the pump stopped the gauge shows the static pressure and is not evaluated. Not linked: the backwash only runs by interval.
NI
 Low water
 Optional. Anything other than 0 means too little water: the filter pump goes off immediately, as do solar, heating and dosing, a running backwash is aborted and a fault is reported. Not linked: low water is never detected.
AO
 Cover open
 Optional. Limit switch, anything other than 0 means reached. Sets the position to 100 % and ends the opening travel. Not linked: control runs without a limit switch - the travel then ends with the configured travel time and no fault is reported for an exceeded travel time.
AZ
 Cover closed
 Optional. Limit switch of the closed position, otherwise as AO. Each direction of travel is considered on its own.
PU
 PV surplus
 Optional. Available surplus in watts. Which sign means surplus is defined by the parameter Surplus: negative is the default and matches the usual grid power - a negative value means feed-in and therefore surplus, a positive one means drawing from the grid. Choose positive if the input already delivers the surplus as a positive value. The input is only evaluated if the parameter PV surplus is not set to Off. Not linked: no surplus is available, so the runtime is caught up instead.
SP
 Lock
 Optional. Anything other than 0 locks: filter pump, solar, heating and dosing go off, a backwash is not started. 0 releases again. Frost protection still runs. Not linked: never locked.
HA
 Manual mode
 Optional. Anything other than 0 keeps the filter pump running for as long as the value is present - regardless of time window, daily target and surplus. This time counts towards the daily target. Not linked: no manual mode through the input, manual operation then runs through the control element.
BA
 Operating mode
 Optional. 0 = automatic, 1 = manual on, 2 = manual off, 3 = winter mode. In winter mode everything stays off, only frost protection is active. Every change cancels a manual mode set in the control element. Not linked: automatic applies.
QU
 Acknowledge
 Optional. Acknowledges a pending fault. The change from 0 to anything other than 0 is evaluated (rising edge). If the cause is still present, the fault is reported again immediately. Not linked: acknowledging then happens through the control element.
RB
 Start backwash
 Optional. Starts the backwash sequence. The rising edge from 0 to anything other than 0 is evaluated. If the sequence is blocked, it is not started and not made up later either. Not linked: it is started by interval, filter pressure, switching time or control element.
AF
 Move cover
 Optional. Anything other than 0 opens, 0 closes. Only the change of the value is evaluated. During the start-up of the controller only the initial value is taken over, nothing starts moving. Not linked: the cover only moves through a switching time or the control element.
BL
 Switch lighting
 Optional. The value is passed on to output BE: anything other than 0 switches on, 0 switches off. Not linked: the lighting is switched through a switching time or the control element.

Outputs

FP
 Filter pump
 1 while the filter pump is supposed to run - in normal operation, in PV operation, while catching up, during the backwash and in frost protection.
FS
 Filter pump speed
 Speed setting in percent for a variable-speed pump. Depending on the operating case the speed for normal operation, PV operation or frost protection applies; during the backwash it is always 100 %. The value is only sent if the output has an address.
RS
 Backwash
 Sets the valve to backwash. It is only switched while the pump is stopped.
NS
 Rinse
 Sets the valve to rinse. It, too, is only switched while the pump is stopped.
SO
 Solar pump
 1 while the solar absorber is being used.
NH
 Auxiliary heating
 1 while the pool is being heated.
DP
 Dosing pump pH
 1 during a dosing cycle of the pH dosing.
DC
 Dosing pump redox
 1 during a dosing cycle of the chlorine dosing.
AA
 Cover open
 With separate control 1 during the opening travel, with the pulse control one pulse per command.
AB
 Cover close
 As AA, but for the closing travel.
BE
 Lighting
 State of the pool lighting.
SR
 Fault
 Collective message: low water, daily dosing limit reached, aborted backwash or exceeded travel time of the cover. The message stays until it is acknowledged. Which cause it is can be seen in the status and in the control element.
ST
 Info status
 All states in one number. Each state has its own bit, several can be set at the same time. The function block Binary decoder splits the value back into the individual states; its output B1 is bit 0.
  • Bit 0 = 1: filter pump running
  • Bit 1 = 1: running because of PV surplus
  • Bit 2 = 1: remaining runtime is being caught up
  • Bit 3 = 1: backwash
  • Bit 4 = 1: rinse
  • Bit 5 = 1: solar pump running
  • Bit 6 = 1: auxiliary heating running
  • Bit 7 = 1: pH dosing running
  • Bit 8 = 1: redox dosing running
  • Bit 9 = 1: cover moving
  • Bit 10 = 1: cover open
  • Bit 11 = 1: cover closed
  • Bit 12 = 1: frost protection
  • Bit 13 = 1: low water
  • Bit 14 = 1: winter mode
  • Bit 15 = 1: manual mode
  • Bit 16 = 1: locked
  • Bit 17 = 1: fault
  • Bit 18 = 1: daily dosing limit reached
  • Bit 19 = 1: maintenance due
  • Bit 20 = 1: lighting on
  • Bit 21 = 1: manual mode is set to off (bit 15 without bit 21 means manual on)
BT
 Operating hours
 Operating hours of the filter pump, counted continuously. They survive a restart and can be reset in the control element.
FW
 Maintenance due
 1 as soon as the operating hours limit set in the control element is reached or the backwash interval has been exceeded considerably.
TS
 Daily runtime target
 Hours the filter pump should run today - from the curve and the presence factor.
TL
 Runtime today
 Hours already run today.
TR
 Remaining runtime today
 Hours still missing. 0 once the daily target is reached.

Parameters

Runtime per day
 Hours per day if no water temperature is linked or no curve is defined.
Time window from / to
 Filtering takes place within these hours. The end is also the latest moment at which the runtime is caught up. An empty or implausible window counts as the whole day.
Distribution
 In one block: the pump runs from the beginning of the time window until the daily target is reached. Spread: the time window is divided into sections of equal length, and part of the time runs in each section. This setting does not apply in PV operation.
Number of sections
 Into how many sections the time window is divided.
Minimum runtime per start
 The pump runs at least this long before it is switched off again. Lock, low water and frost protection act immediately.
Speed in normal operation
 Setting for output FS outside PV operation and frost protection.
Hour of day change
 At this hour runtime and dosing quantities start at zero again.
PV surplus
 Off: the runtime is only distributed over the time window. Preferably on surplus: the pump runs on surplus, the rest is caught up towards the end of the time window. Only on surplus: nothing is caught up.
Surplus
 Sign of the value at input PU. Negative (default): a negative value means feed-in and therefore surplus - that is how a grid power measurement reports it. Positive: the input already carries the surplus as a positive value.
Power of filter pump
 Power consumption of the pump. It is switched on as soon as the surplus reaches this power plus the minimum.
Minimum surplus
 This much surplus should remain; below that the pump is switched off. If the measurement does not deliver negative values when drawing from the grid, a value greater than 0 should be entered here.
Control time
 How often the decision to switch on or off is taken. A slow value keeps the pump from switching with every passing cloud.
Minimum runtime per PV start
 The pump runs at least this long after a start caused by the surplus.
Speed in PV operation
 Setting for output FS while the pump runs because of the surplus.
Catch-up margin
 The catch-up starts this much earlier than the remaining time would require.
Backwash
 What triggers the sequence: nothing, the interval, the filter pressure or both. Regardless of this it can be started through input RB, a switching time and the control element.
Interval
 Days between two backwashes.
Filter pressure limit
 Above this pressure a backwash is started. Only evaluated while the filter pump is running.
Time of backwash
 At this hour it is checked whether the interval has elapsed.
Backwash / rinse duration
 How long the pump runs in the respective step.
Valve switching time
 The pump stands still this long before and after every valve change.
Blocked while cover closed
 Prevents the backwash while the cover is closed.
Solar absorber
 Switches the solar control on.
Switch-on / switch-off difference
 By this much the collector must be warmer than the water for the solar pump to start, and below that it is switched off. The switch-off difference must be smaller than the switch-on difference.
Maximum temperature water / collector
 Two separate limits: pool protection and collector protection.
Minimum runtime solar pump
 The solar pump runs at least this long after it has started.
Solar and filter pump
 Independent: the solar pump also runs without the filter pump. Only while the filter pump runs: it waits for it. Start the filter pump: the function block requests the filter pump; this time counts towards the daily target.
Solar while cover closed
 Blocks the solar control while the cover is closed.
Auxiliary heating
 Switches the auxiliary heating on. The setpoint is set in the control element.
Hysteresis auxiliary heating
 By this much the water must fall below the setpoint before heating starts.
Heating and filter pump
 As with Solar and filter pump: independent, only while the pump runs, or start the pump as well.
Heating from / to
 Time window in which heating is allowed.
pH dosing
 Lower pH doses when the reading is above the setpoint, raise pH when it is below.
Tolerance pH / redox
 Dosing only starts at a larger deviation from the setpoint.
Redox dosing
 Switches the chlorine dosing by redox value on.
Lead time filter pump
 The filter pump must run this long before dosing starts - before that the reading is not meaningful.
Dosing time per cycle / pause per cycle
 Duration of one dosing cycle and the pause afterwards during which the agent is distributed in the pool.
Maximum duration per day
 Hard limit per dosing pump. Once it is reached, no further dosing takes place and a fault is reported.
Cover
 None: the outputs are left untouched. Separate control: AA and AB are set during the travel. Pulse: one pulse per command goes to the respective output.
Travel time cover
 Time for a full travel. Basis of the position estimate; without a linked limit switch the travel ends with it.
Pulse duration cover
 How long the pulse is present at the output.
Filter pump during travel
 Switches the filter pump off while the cover is moving.
Frost protection below
 Below this outside temperature the filter pump runs.
Hysteresis frost protection
 By this much the outside temperature must rise again before the frost protection ends.
Speed frost protection
 Setting for output FS during frost protection.
Push message
 Sends a push message to the apps when a fault occurs.


See also the general parameters of all function blocks.