Preamp Connector; Trigger Input - Stanford Research Systems SR810 Manual

MONITOR OUT
TRIG IN
TTL OUT

PREAMP CONNECTOR

X Output = (X/sensitivity - offset)xExpandx10V
Y Output = (Y/sensitivity - offset)xExpandx10V
where the offset is a percentage of full scale and the expand is an
integer from 1, 10 or 100. The X offset and expand are set from the front
panel. The Y offset and expand may only be set from the interface.
Overloads on Y are not reported by the SR810.
This BNC provides a buffered output from the signal amplifiers and
prefilters. This is the signal just before the A/D converter and PSD. The
output impedance is <1 Ω and the output current is limited to 10 mA.
The gain from the signal input to the monitor output is the overall gain
minus the dynamic reserve minus 3 dB. The overall gain is 10 V divided
by the sensitivity. The actual dynamic reserve is specified in the
description of the [Reserve] key. For example, if the sensitivity is 10 mV,
the gain is 60 dB. If the dynamic reserve is 20 dB, then the gain from the
input to the monitor output is 60-20-3=37 dB or a gain of 71. A 10 mV
(rms) input will result in a .7 Vrms or1 Vpk output. The gain is only
accurate to about 1.5 dB or 20 %.
This output is useful for determining the cause of input overloads and the
effects of prefiltering. However, because the analog gain never exceeds
2000, very small signals may not be amplified enough to viewed at the
monitor output.
This TTL input may be used to trigger stored data samples and/or to
start data acquisition. If Trigger Start is selected, then a rising edge will
start data storage. If the sample rate is also Trigger, then samples are
recorded at every subsequent trigger. (The first trigger starts the scan
and takes the first data point, subsequent triggers record the rest of the
data points.) When the sample rate is set to Trigger, samples are
recorded whenever there is a rising edge at the Trigger input. The
maximum sample rate is 512 Hz. Data storage is available through the
computer interface only.
This output is the TTL sync output for the internal oscillator. The output is
a square wave whose edges are linked to the sine wave zero crossings.
This is useful when the sine output amplitude is small and a synchronous
trigger is required (to a scope for example). This output is active even
when locked to an external reference.
This 9 pin "D" connector provides power and control signals to external
preamplifiers such as the SR550 and SR552. The power connections
are described below.
Pin Voltage
1 +20V
2 +5V
6 -20V
7 Signal Ground
8 Ground
4-25
Rear Panel