P30
UDP interface: Guidelines
UDP Programmers Guide V2.01
13
© KEBA
2.5
Current control
Please note that AC (alternating current) charging stations do not control/
change the charging current directly. AC charging stations use a PWM
(pulse width modulation) signal to communicate the maximum allowed
charging current to the vehicle as specified in IEC 61851-1. All P30 are AC
charging stations. The actual current is solely controlled by the vehicle. If the
wording used in this document indicates a current change, the actual mean-
ing is always a change in the maximum allowable current (target current)
communicated to the vehicle.
P30 complies with IEC 61851-1. This international standard requires a mini-
mum waiting time between two consecutive current changes. To fulfill this re-
quirement, all P30 will delay the execution of UDP commands requesting a
current change during a charging session. The affected commands are
cur-
rtime
and
curr
. The request to stop charging via
currtime 0 1
will not be
delayed and executed as soon as possible.
When a command, either
currtime
or
curr
, sets a new value for “Curr user”
the device prepares to change the target current within the next 6-7 sec-
onds. If another current change is requested via UDP command during this
period of time the target current will be overwritten but the timer will not re-
set. The following examples illustrate the system behavior:
Example 1
10:07:19
curr
command changes the value of “Curr user” immediately.
10:07:19
Internal timer starts at the same moment.
10:07:25
The change in the target current is executed and the value of “Max curr” is
changed.
Example 2
09:46:09
The first
currtime
command initiates a change of the target current.
09:46:10
The field “Curr user” is updated and the internal timer starts.
09:46:11
The second
currtime
requests another current adaptation.
09:46:12
The field “Curr user” is updated again but the internal timer is already running.
09:46:16
The change in the target current is executed and the value of “Max curr” is
changed to the value sent by the last command.
