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POS-123-*-2030
7.8.10
IMS (Theoretical maximum current drain)
In order to offer a safe protection against overheating of the coil in case of a hardware failure, the use of an
up-stream electronic overload protection may be required.
Further information about this topic can be taken from the document AN-
102: „proportional magnet coils in
Ex
– protection areas”.
With the parameter IMS it is possible to limit the current drain of the power amplifier in a way that even under
adverse conditions the overload protection will not trigger if there is no hardware fault. The function does not
delimit the dynamics of the system and the full solenoid current is preserved as long as possible. The limiting
function calculates the current drain by considering the solenoid current and the duty cycle of the PWM signal.
Therefore its precision is affected by the PWM frequency, but it is always sufficient in order to avoid triggering
the protection switch.
Preset value of the parameter is 2600 mA and this means it is inactive. Activation of the function is achieved
by setting IMS < CURRENT. The rated current of the protection switch should be entered.
Command
Parameter
Unit
Group
IMS
x
x= 500 … 2600
mA
EXP
