Data Sheet

PmodISNS20™ Reference Manual

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Page 3 of 3

The scaling value at the beginning of the equation was derived using the provided sensitivity of 66mV/A off of the

ACS722 datasheet. Note that the provided sensitivity is based on a reference voltage of 3.3V to the sensor and our

design provides a regulated 3.0V for a cleaner signal, so some more correction may be needed if absolute accuracy

is needed.

Table 2 below shows how to configure the sampling rate frequency. The current sensing chip allows either 20 kHz

or 80 kHz sampling rate which is configured with Jumper 2. Enabling Jumper 1 turns on an analog filter to bring it

down to 120 Hz. The lower frequency is useful to keep noise down on <120 Hz AC circuit applications, such as

reading from mains power.

Rate

JP1

JP2

120 Hz

Enabled

120 Hz

Enabled

Disabled

20 kHz

Disabled

Enabled

80 kHz

Disabled

Table 2. Sample rate frequency configuration.

In order to read the amperage flowing through the ISNS20, the power source will need to be wired in series

through the green terminal block, noting proper polarity indicated by the silkscreen on the PCB. When using the

ISNS20 for measuring Alternating Current (such as from mains), absolute care should be taken. Improper use of the

ISNS20 on mains power can result in fire, injury, and even death – extreme caution should be taken.

Any external power applied to the PmodISNS20 must be within 3.0V and 3.6V; however, it is recommended that

Pmod is operated at 3.3V.

3 Physical Dimensions

The pins on the pin header are spaced 100 mil apart. The PCB is 1.3 inches long on the sides parallel to the pins on

the pin header and 0.8 inches long on the sides perpendicular to the pin header.