Agrowtek SXH, Instruction Manual

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© Agrowtek Inc. | www.agrowtek.com

Calibration registers are 16-bit signed integers for the purpose of calibrating the sensor values or analog out-

put channels. Calibration may be achieved by writing the desired calibrated value to the associated register. 

Writing to the calibration registers automatically invokes the calibration routine for that register. 

Offset Calibration

Offset, or zero calibration, is an arithmatic positive or negative correction to the sensor reading. Operations 

performed using the offset register are:

-Temperature calibration

-pH 7 calibration

-Conductivity, ORP or DO zero calibration

To perform a sensor offset calibration, simply write the corrected sensor value to the offset calibration reg-

siter (taking into account the integer scale as shown above.)

To set the temperature to a calibrated value of 25°C, write the value “2500.”

To set the pH 7 calibration, write the value “700.”

To set the conductivity zero calibration, write the value “0.”

Span Calibration

Span, or slope calibration, corrects the slop of the sensor reading at a second point, away from the zero cali-

bration. Operations performed using the span register are:

Calibration Registers

Sensor values are available in integer or floating point formats depending on the register requested (see 

map.) 

Sensor Value Registers

Sensor #

Type

Integer Scale

Range

1

Temperature

x100

-2000 - 6000 (-20 - 60°C)

2

pH

x100

0 - 1400 (0 - 14.00pH)

3

Conductivity

x1

0 - 5000 microSiemens

4

O.R.P.

x1

-1000 -  +1000 mV

D.O.

x100

0 - 4000 (0 - 40.00 mg/L max, per cal)

For example: an integer temperature value of 2417 is equal to a temperature reading of 24.17°C.

0x03 Read Multiple Registers

0x06 Write Single Register

0x10 Write Multiple Register

Supported Commands

All registers are 16 bits wide with addresses using the standard MODICON protocol. Floating point values 

use the standard IEEE 32-bit format occupying two contiguous 16 bit registers. ASCII values are stored with 

two characters (bytes) per register in hexadecimal format.

Register Types