Electrical Connection Method Of D6F-Ph - Omron D6F-PH User Manual

6-2. Electrical connection method of D6F-PH

For the I2C output, the D6F-PH will require a pull-up resistor to each clock line(SCL) and
data line (SDA). A pull-up resistor of 2.2[kΩ] (recommended value) should be implemented
between the Vcc as shown in Fig.6. In addition, please adjust the pull-up resistor's value
depending on the transfer rate of SCL and the I2C wire length.
* Precautions when connecting the flow sensor
An error may occur during communications due to the effect of the noise of the customer's environment.
In such a case, check the following points, and correct the communications error.
(1) Checking the communications speed
This product supports an SCL frequency of up to 400 kHz, however, if there is a likelihood of
occurrence of a communications error, we recommend using the SCL frequency at 100 kHz.
(2) Checking the wiring cable
If the length of the cable used to connect the customer-controlled microcontroller and an OMRON
flow sensor is long, the effect of noise may be more prominent. In such a case, OMRON
recommends using a shielded cable.
(3) Checking the pull-up resistor's value
A pull-up resistor is necessary for I2C communications of this product. Although the recommended
resistor value is 2.2[kΩ], please select the optimum resistor value according to the length of the cable
used to connect the customer-controlled microcontroller and the OMRON flow sensor. A
communications error is judged unless an ACK is returned from the sensor side. The ACK response
time is equal to one clock cycle of SCL. If an ACK response is not returned after this time has
elapsed, it results in a communications error. In such a case, turn off the device.
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Fig. 6 Electrical connection method of D6F-PH
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