Ametek Sorensen XEL 15-5, Operation Manual

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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.
Constant Voltage Control
Constant Current Control
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
out
and I
out
are generated from the actual internal control voltages,
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
out
and I
out
are scaled such that 0 to
100% of the rated output voltage and current (high range only) generate 0V to 5V at the rear
panel V
out
and I
out
terminals with respect to COM. COM is connected to the positive output.
I
out
always corresponds to the set current, whether the output is on or off, but V
out
goes to 0V when
the output is off.
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