cFos Charging Manager - Formulas

The cFos Charging Manager allows the dynamic evaluation of formulas. This functionality is available for a meter of the type "Expression" and for charging rules of the type "Formula".

You can therefore set up meters that calculate values from other meters or EVSEs and keep them ready and display them. The charging rules can also use formulas to dynamically calculate the charging current and also access meters and EVSEs (including meters of the "Expression" type).

The following operations are possible with the formulas:

`+ - * / %`	Addition, subtraction, multiplication, division, modulus
`& \|`	bitwise AND and OR
`^`	Power calculation, e.g. 10^2 = 100
`min(x,y)`	Minimum of x and y, more than 2 arguments possible
`max(x,y)`	Maximum of x and y, more than 2 arguments possible
`abs(x)`	Absolute value of x, e.g. abs(-2) = 2
`clamp(x,min,max)`	Value x = min (if x < min), x = max (if x > max), otherwise keep x
`sqrt(x)`	Round x to whole number. Example: Rounding to 1 decimal place: round(10*x)/10.
`sqrt(x)`	Square root of x
`exists(x)`	true if the variable x exists, otherwise false

Furthermore, the following logical expressions are possible:

== (equal), != (unequal), < (less), <= (less-equal), > (greater), >= (greater-equal), ! (not), || (logical Or), && (logical And), ? (conditional operator, e.g. x ? y : z, returns y if x is true, otherwise z)

This allows, for example, the current to be switched off depending on conditions: M1.current >= 6500 ? M1.current : 0 returns the current of M1 if it is greater than 6.5A and 0 otherwise, which pauses the charging. For such conditions, it is also possible to query inputs (see below)

The following names are possible:

Mx	Meter with unit ID x, e.g. M1
Ex	EVSE with device ID x, e.g. E1

It is also possible to access virtual meters, such as solar surplus, grid draw or "Power avail. for EVSEs" (power available for wallboxes), by setting up the meter and then using the corresponding device ID in the formula.

You can then access individual values of the units by means of the point. These are called as follows:

current_l1	Current of phase 1 in mA
current_l2	Current of phase 2 in mA
current_l3	Current of phase 3 in mA
current	Current of the current phase in mA (for charging rules, the Charging Manager queries all phases one after the other; for meters of the type "Expression", the respective phase to which the formula refers applies. If you have specified a formula for "Current L1", you can omit the fields for Current L2 and L3. Then the formula for current L1 is used)
power_va	Current power in Watt/VA (depending on the meter type, apparent power or active power can be supplied here)
power_w	Current active power in watts
opower_va	Wallbox: Current power offered in VA related to all 3 phases.
import_wh	Energy drawn in Wh
export_wh	Injected energy in Wh
dt	The time that has elapsed since the last past update (in seconds)
inputN	Input number N of the unit, 1 = active, 0 = inactive
soc	SOC, charge level in percent (meter/storage)
id	Device Id, Modbus ID
txn_duration	Duration of the current transaction in seconds (EVSE)
txn_energy	Charged energy of the current transaction in Wh (EVSE)
min_current	Minimum charging current in mA (EVSE)
max_current	Maximum charging current in mA (EVSE)
state	Status: 1 waiting, 2 plugged in, 3 charging, 4 charging with ventilation, 5 error, 6 offline (EVSE)
cphases	Number of charging phases (0-3)
pphases	Number of predicted charging phases (0-3)
budget	KWh on the current budget
budget_amount	On the current budget maximum kWh
budget_used	KWh used on the current budget
com_err	1, if there is a COM error, otherwise 0
com_err2	1, if a COM error is present for longer than 12 sec, otherwise 0

Example

M1.current_l1	Current of meter M1, phase 1
E2.import_wh	Consumed Wh of the EVSE E2
E3.power_va	Current charging power from E3

If you use the formulas for a meter of type "Expression", you can also omit the device ID. Then the field names refer to this meter, e.g. 'power_va' is then the power of this meter in Watt/VA. You can use 'dt' to realise a few extended functions, e.g. in a meter of the type "Expression":

As a formula for 'import_wh': import_wh + M1.power_va * dt / 3600 updates the sourced energy based on the power during the past update time
As a formula for 'power_va': (power_va * (20 - dt) + M1.power_va * dt) / 20 smoothes the power over the last 20 seconds.

Global variables

date

date.year	Current year
date.month	Month from 0..11
date.day	Day from 1..31
date.weekday	Weekday Mo=0, Tue=1, ... Sun=6
date.yearday	Day in the year from 0..366
date.hour	Hour from 0..23
date.minute	Minute from 0..60
date.second	Second from 0..60
date.daysecond	Second of this day from 0..86399
date.dayminute	Minute of this day from 0..1439
date.dst	0 = winter time, 1 = summer time

PB (cFos Power brain only)

PB.input1	S0 Input 1, 1 = active, 0 = inactive
PB.input2	S0 Input 2, 1 = active, 0 = inactive

CM Charging Manager variables

These variables can be set by the admin under "Configuration". For example, if the admin sets the variable 'var_x' to 1.5, CM.var_x returns the value 1.5.

Predefined variables:
_num_charging: Number of wallboxes currently charging
_num_charging1: Number of currently charging wallboxes, 1 if none is charging
_max_total_current: Maximum current of the house connection in mA per phase
_max_total_evse_current: Maximum current for wallboxes in mA (per phase)
_price: Current electricity price
_price_level: Current electricity price level, -2=very expensive, -3=expensive, -4=normal, -5=cheap, -6=very cheap _surplus: Current solar surplus in watts _org_surplus: Solar surplus as would have been calculated by the Charging Manager independently of its own formulas

Benutzung der globalen Objekte:
charge 8A starting at 8:00am: date.dayminute >= 480 ? 8000 : 0
charge 16A on Saturday and Sunday: date.weekday == 5 || date.weekday == 6 ? 16000 : 0
charge 6A if input 2 active: PB.input2 ? 6000 : 0 charge 6A if CM variable non-zero: cm.var1 ? 6000 : 0

Application example

You want to additionally limit the charging current with regard to a consumption meter of a flat. To do this, you can set up a charging rule with the formula 16000 - M1.current.
M1 is the meter that measures the consumption of the flat. The load management of the cFos Charging Manager first tries to provide the EVSE with the maximum current in relation to the house connection power, but then limits this to 16A minus the consumption of the flat.