Ametek Sorensen XEL Serie Manual De Instrucciones página 27

OVP and OCP
OVP (over-voltage protection) and OCP (over-current protection) are implemented in firmware
and can only be set and used when under remote control via the RS232, USB, LAN (LXI) or
GPIB interfaces. Setting resolutions are 10mV and 1mA and typical response times are 500ms.
However, in local mode, OVP and OCP are still active but automatically default to 105% of the
instrument's range maximum. This usefully provides shut-down protection in the event of
prolonged application of a CV or CC control voltage which attempts to set the output beyond
105% of the range maximum.
Practical Considerations when using CV and CC
The stability of the control voltages directly affects the stability of the output. Any noise on the
control signals will generate noise on the output. To minimize noise on the output connect the
control voltages to the CV, CC and COM inputs using twisted or screened pairs (screens
grounded at one end only) and keep the connections as short as possible. The diagrams below
show the connections for Constant Voltage (CV) and Constant Current (CC) control using an
external voltage.
Note that when the OUTPUT is on, the instrument's display always shows the actual output
voltage and current, whichever control source is active. However, when the OUTPUT is off, the
display will show the preset voltage and current set by the front panel controls (or the digital
interface if active) and not the values determined by the CV and CC inputs even if they have
been made active (CV and CC set to Remote). To avoid confusion it is good practice to set the
front panel controls to minimum when remote CV and CC are used.
Analog Out Control Voltages
Analog Out control voltages V
for which the active source can be the front panel controls, the digital interface (RS232, USB,
LAN or GPIB) or the remote analog inputs CV and CC. V
100% of the rated output voltage and current (high range only) generate 0V to 5V at the rear
panel V and I terminals with respect to COM. COM is connected to the positive output.
out out
Constant Voltage Control
Constant Current Control
and I are generated from the actual internal control voltages,
out out
and I
out
are scaled such that 0 to
out
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