Zilog ZEPIR0BA - Manual (Page 13)

UM026001-0413 Sensitivity
ZMOTION ® Detection Module II Evaluation Kit
User Manual
9
provided in the kit to demonstrate this function. When light shines on the photocell, its
resistance decreases, thereby providing a lower voltage to the light gate (LG) signal on the
ZMOTION Detection Module II. When the module detects this voltage to be below 1.0 V
in Hardware Mode or the programmed threshold in Serial Mode, the MOTION LED (/MD
signal) will not activate when motion is detected. The AMBIENT potentiometer (R6) sets
the amount of ambient light required to cross the threshold.
Sensitivity
The amount of motion required to trigger the MOTION LED (/MD signal) can be adjusted
using the SENS potentiometer (R3). This adjustment also has the effect of controlling the
range that the detector can see—lower sensitivity reduces the range of the detection pat-
tern. The SENS potentiometer provides a voltage between 0 V and 1.8 V to the TXD/SNS
signal on ZDM II. A higher voltage means lower sensitivity. The SENS potentiometer is
used only in Hardware Interface Mode. In Serial Interface Mode, the sensitivity is set via
commands sent over the serial interface.
/MD Output Delay Time
The amount of time that the MOTION LED (MD signal) is activated can be controlled by
the DELAY (R4) potentiometer. You can set this range between 2 seconds and 15 minutes.
This feature is typically used in power control applications in which the amount of time
that a device is activated must be controlled. The potentiometer provides a voltage
between 0 V and 1.8 V to the RXD/DELAY input on the ZMOTION Detection Module II.
A higher voltage yields a longer activation time.