THORLABS PICO D User Manual page 19

2.5.1 Grounding issues
Before connecting PICO D to any electrical power or signal source care must be
taken to avoid ground loops. The ground loops may pick up noise and/or other dis-
turbances from the surrounding electromagnetic environment. Such disturbances
may lead to reduced performances (or malfunctioning) of PICO D.
There are two connectors on the rear side of PICO D, see Figure 2–8; one connec-
tor for electrical power, and one connector for the control and status signals. Both
connectors have pins connected to ground. ALL pins (see Table 2-10 and Table
2-11) labeled GND are physically joined inside PICO D.
We recommend that PICO D is connected to the (signal)ground via the electrical
power connector (in Table 2-10, all Row B pins are 0 V and physically joined). This
connection scheme ensures that the +5 V, +15 V and –15 V supplies can be used to
supply the user's control electronics. However, a ground connection between the
Row B pins (in Table 2-10) and the ground of the user's control electronics must be
made.
The three analog control voltages (TUNING_VOLTAGE, OPTICAL_POWER, and
MODE_HOP_ADJUST) are connected to differential input stages having high
CMRR. Hence, it is not recommended that any of the analog control voltages termi-
nals are grounded. See Figure 2–9.
Signal
_TEMPERATURE_ERROR
_WAVELENGTH _ERROR
_OPTICAL_POWER_ERROR
Type Note
Digital status TRUE = 0 V
FALSE = +5 V
Internal temperature
Digital status TRUE = 0 V,
FALSE = +5 V
Digital status TRUE = 0 V
FALSE = +5 V
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