User Manual
2253i / 2253iX
AMETEK
California Instruments
109
8.4 External Input (-EXT)
The –EXT option is factory installed only. If installed, this option disables the internal controller
waveform generation, voltage, current limit and frequency programming as well as output relay control.
Instead, a user provided AC signal is used to drive each amplifier. A 0 to 5 Vrms AC signal will provide
a 0 to 300 Voltage output on the 300V AC range. The 150V AC range is not available on EXT models.
If the input signal exceeds ±7.5 Vpk on the 300 V range or ±3.75 Vpk, the output waveform will start to
clip (flat top) so the rms level of the output is limited by the crest factor of the external input signal(s).
The presence of the EXT option is indicated by the –EXT field in the model number on the serial tag.
Note that the –EXT and –RPV options are mutually exclusive so only one or the other can be present.
8.4.1 Important EXT Option Considerations
Input signal range:
Since the controller has no control over the output voltage and frequency, it is
important not to exceed the available voltage and frequency output range of the amplifier. The
amplifiers are used in an open loop mode so no ALC mode is available to improve load regulation. For
supplementary specification for –EXT operation, refer to section 2.9.
Output Relay:
Since the power source does not control the amplifier drive signal, the output relay
control button (OUTPUT ON/OFF) has been disabled leaving the output relay in the CLOSED state at
all times. This ensures the output relays cannot be switched hot. To turn “off” the output, the external
input signal must be set to 0V.
Turn on requirements:
When turning on the power source, it is recommended to make sure the EXT
input signal(s) is/are 0V or disconnected to prevent irregular output from occurring.
Also, to ensure the power on measurement zero calibration that occurs any time the power source is
turned on operates correctly, it is necessary to disconnect the external signal inputs or make sure they
are at 0Vrms with no DC offset present and disconnect any load if possible. If not, the measurements
displayed by the power source may not be correct.
Measurements:
Measurement functions of the controller are available even on EXT configured units
but frequency measurements at very low AC output voltages (< 10Vrms) are not accurate.
Note: To use the EXT mode, the above guidelines must be followed.
8.4.2 Connections
The RPVA, EXTB and EXTC inputs on the Auxiliary I/O conenctor are used to connect the external
input signals if the –EXT option is installed. The RPVA input is used if the RPV option is installed
instead. A suitable 15 pin DB15H high density mating connector is provided in the ship kit and can be
use to connect the external oscillator signals. See Table 3-6: DB15 Auxiliary I/O Connector for pin out
information.
8.4.3 Front Panel Setup
Power sources configured with the EXT option always operate in external signal input mode on the
300V AC range. That means no voltage, frequency, current limit or output on/off programming is
available using the front panel or the bus.
The VOLT REF setting in the CONTROL menu is fixed. Refer to the CONTROL menu for setting
information. Section 4.2.5.
Содержание 2253i
Страница 5: ...User Manual 2253i 2253iX AMETEK California Instruments 5 SAFETY SYMBOLS...
Страница 99: ...User Manual 2253i 2253iX AMETEK California Instruments 99 Figure 6 1 Internal adjustment locations...
Страница 118: ...User Manual 2253i 2253iX AMETEK California Instruments 118 Figure 9 4 Voltage Modulation Frequency characteristics...
