Remote Voltage Control; Remote Level Select; Remote Input Disable; Remote Control - Aim TTi LD300 Manual De Instrucciones

Two forms of voltage controlled remote operation are available: EXTERNAL VOLTAGE control,
where an analogue voltage defines the demanded level of the chosen operating mode, and
EXTERNAL TTL control where an external voltage selects between the level settings of the
LEVEL A and LEVEL B front panel controls.
The controlling voltage is applied to the two CONTROL VOLTAGE terminals on the rear panel.
Each terminal has an input impedance of nominally 400kΩ to the load negative terminal. A
differential line receiver allows common mode voltages up to ±100 Volts. The common mode
rejection is better than –66dB (50mV at 100V); although it is typically much better than this
(-80dB), the effect on the programmed level can be significant. Consideration should also be
given to the return path for the input currents.

Remote Voltage Control

Set the LEVEL MODE switch to EXTERNAL VOLTAGE position. The front panel LEVEL A and
LEVEL B controls have no effect. The LOAD MODE switch selects the required operating mode
and full scale range. The front panel DROPOUT voltage control setting remains active.
The CONTROL VOLTAGE input has a scaling factor of 4 Volts full-scale. The conversion factors
for each mode and range are:
The slew rate circuit and its front panel controls remains in circuit and the required transient
waveshape can be obtained by adjusting these settings in combination with the shape of the
signal applied to the remote input, subject to the transition time limitations of the load circuit.

Remote Level Select

Set the LEVEL CONTROL switch to the EXTERNAL TTL position. If the external signal applied to
the CONTROL VOLTAGE input is below the logic threshold (nominally + 1·5 V) then the level set
by the LEVEL A control is active; if the signal is above the threshold then the level set by the
LEVEL B control applies. The transitions are defined by the setting of the SLEW RATE controls
on the front panel.

Remote Input Disable

This input is provided for remote override of the INPUT ENABLE function of the load. It is
available in all operating modes of the instrument. It is a fully floating input to an opto-isolator:
apply 3 to 12 volts (observing polarity) to disable the load. The load is only enabled if this signal
is absent and the front panel INPUT ENABLE switch is depressed.
Operating Range Scale Factor
80 Amps 20 Amps per Volt
8 Amps 2 Amps per Volt
80 Volts 20 Volts per Volt
8 Volts 2 Volts per Volt
320 Watts 80 Watts per Volt
400 Ohms 100 Ohms per Volt
10 Ohms 2·5 Ohms per Volt
1 A/V (Siemens) 0·25 A/V (Siemens) per Volt
40 A/V (Siemens) 10 A/V (Siemens) per Volt

Remote Control

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