The operation description in the manual provides key details for each step. By organizing the complete process and following it, most mistakes can be avoided, especially for those links that are most likely to cause difficulties for novices when they operate independently for the first time.

Step 1: Instrument preparation

Before starting the machine, check whether the bath liquid (usually distilled water, or glycerin for high-temperature testing) in the bathtub is sufficient - the liquid level should be 5-8cm from the lower edge of the upper cover. When the liquid level is too low, the heating efficiency decreases; when it is too high, the liquid may overflow or enter the capillary tube.

Use a level meter (with a built-in level bubble on the top cover) to check the horizontal status, and rotate the four adjusting studs at the bottom of the instrument until the bubble is centered. The capillary must be kept vertical, as inaccurate horizontal alignment can cause the direction of liquid flow to be skewed, leading to increased timing errors.

Step 2: Parameter setting

Press the "Parameters" button to enter the settings interface, and confirm in sequence:

Set temperature: Set to 40℃ for viscosity measurement at 40℃, and set to 100℃ for viscosity measurement at 100℃

Capillary constant: The corresponding numbers of the four viscosity tubes and their respective calibration constant values (read from the tube wall engraving)

Number of experiments: According to national standards, it is required to conduct 4 experiments, and it is generally set to 4

Fine-tune temperature: If there is a discrepancy between the temperature displayed on the screen and the reading from an external thermometer, make a compensation here (range -3.0 to +3.0℃)

After setting the parameters, press "Save". The instrument will retain the settings even if powered off, so there's no need to reset them the next time it is turned on (but it's a good habit to verify them before each use).

Step 3: Sample loading and preheating

Fill the capillary with the sample: Attach the rubber tube, invert the viscometer tube, insert the sample container, use the ear syringe to suck the liquid up to the upper mark, remove the viscometer tube and restore it to an upright position, wipe off the residual liquid on the outer wall of the tube, and move the rubber tube to the branch tube opening.

Place the sample-filled capillary tubes into the bathtub, and use the additional holes to place preheating tubes (tubes filled with oil but not yet in the testing sequence). Preheat them in advance to ensure better temperature consistency.

Step 4: Wait for constant temperature

After the temperature reaches the set value, the instrument prompts "Press the start button to proceed with the measurement once ready". However, one cannot immediately proceed with the measurement - the instructions clearly state that after placing the capillary tube in the bath, one must wait for an additional 15 minutes after the temperature reaches the set value before starting the experiment. This 15-minute waiting period is necessary to allow the internal temperature of the sample to fully equilibrate with the bath temperature. Rushing to test can lead to lower results.

Step 5: Timing and Measurement

Select the appropriate capillary tube number, draw up oil to make the liquid level slightly higher than the upper mark, and observe the flow. When the liquid level reaches the upper mark, press "Start", and when it reaches the lower mark, press "Stop". The instrument will display the flow time for this measurement. Repeat the operation according to the set number of times. After completion, the instrument will automatically calculate the viscosity result. Press "Save" to store it in the history, and press "Print" to generate a paper output.