
① —— Conductivity measurement mode icon.
② —— Measured value.
③ —— Calibration mode icon (CAL) and serial number
④—— Unit of measurement.
⑤——Temperature unit (℃ and ℉).
⑥—— pH and conductivity units displayed during calibration.
⑦—— pH and conductivity values displayed during the calibration process; data storage and echo numbers; and prompt symbols for special display modes.
⑧—— Icons for data storage and echo:
M+ — icon for storage of measured value; RM — icon for echo of measured value.
⑨——Temperature value; and the prompt symbol of special display mode.
⑩ —— Self-diagnosis icon and number
⑪ —— Temperature compensation status icon:
ATC — Automatic Temperature Compensation; MTC — Manual Temperature Compensation.
⑫ —— Calibration indicator icon.
⑬ —— The reading is stable and the icon is displayed.
⑭—Maximum and minimum icons (see clause 3.6)


Short press—key time <1.5s; long press—key time>1.5s.

Table-3 Socket of PH400 desktop pH meter
| symbol | socket name | socket type |
| REF | Reference electrode socket | Φ2 banana type |
| pH/mV | Sockets for pH and ORP electrodes | BNC type |
| TEMP | temperature socket | RCA type |
| DC9V | DC9V power socket | Φ2.5 In-line type |

Table-4 Socket of CD400 Desktop Conductivity Meter
| symbol | socket name | socket type |
| COND | Conductivity Electrode Socket | BNC type |
| TEMP | temperature socket | RCA type |
| DC9V | DC9V power socket | Φ2.5 In-line type |