Ametek 2003RP, User And Programming Manual

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4.4 Current Limit Modes
The 2003RP supports two modes of current limiting. In either mode, the user can set the
RMS current level at which the current limit function will operate. The available current limit
modes are:
Constant Current (CC) mode This is the default mode as supplied from the
factory. In this mode, the output voltage is
automatically reduced by the AC power source to
maintain the set current. Once the current drawn
drops below the set limit value, the voltage is
increased again. No error message is generated
in this mode of operation. This mode is suitable
for starting loads that require high inrush currents
but don‟t need full nominal voltage to run. (e.g.
AC motors).
Constant Voltage (CV) mode In this mode of operation, the output of the AC
source is turned off and the programmed voltage
is set to 0 volts as soon as the load current
exceeds the set current limit value. (Trip current).
Changing jumpers in the AC power source will change the selected current limit mode. Refer
to section 3.9 for instructions on how to change these jumpers.
4.5 Function Strobe [Option]
The Function Strobe (FS) is a TTL logic level signal provided at the rear panel of the
2003RP. This signal is synchronized to any phase A voltage and frequency output change of
the AC source and may be used to trigger external test equipment such as oscilloscopes.
Default mode of operation
The function strobe is an active low TTL output signal. Each pulse lasts approximately 400
sec . The output changes on the falling edge of the function strobe signal.
Alternative mode of operation
The function strobe output logic uses the GPIB interface DC supply to provide the required
logic levels. If the GPIB interface is connected to the user‟s PC, excessive ground noise may
prevent the function strobe from operating correctly. If this is the case, the output mode of
the function strobe may be changed to provide a floating open collector output. In this case,
the end user has to provide an external DC power supply and pull-up resistor. A 9 volt
battery may be used for this purpose
. Contact California Instruments‟ service department for
details on changing the operation of the FS output.