Specifications

MODEL 30 pH/DO SECTION 6.0

CALIBRATION

6.7 ENTERING A KNOWN SLOPE VALUE — pH

6.7.1 Purpose

If the electrode slope is known from other measurements, it can be entered directly in the Model 30 transmitter.

The slope must be entered as the slope at 25°C. To calculate the slope at 25°C from the slope at temperature t°C,

use the equation:

slope at 25°C = (slope at t°C)

Changing the slope overrides the slope determined from the previous buffer calibration.

6.7.2 Procedure

CCaalliibbrraattee

Hold

Program Display

Calibrate?

Sensor1

SSeennssoorr22

CalSensor2?

MMeeaassuurreemmeenntt

Temp

pH Slope @ 25°C?

S2: 59.16mV/pH

Changing slope

overrides bufcal.

Invalid Input!

S2 Standardize

SSllooppee

BufferCal

S2 Standardize

SSllooppee

BufferCal

1. Press MENU. The main menu screen appears. Choose Calibrate.

2. Choose Sensor2 (pH sensor).

3. Choose Measurement.

4. Choose Slope.

5. The screen at left appears briefly.

6. Change the slope to the desired value. Press ENTER.

7. The slope must be between 45 and 60 mV/pH. If the value entered is out-

side this range, the screen at left appears.

8. If the entry was accepted, the screen at left appears.

9. To return to the main display, press MENU followed by EXIT.

298

t°C + 273