The transmitter APM-X in a field or panel housing offers a convincing solution for all applications in the area of water and waste-water treatment as well as in industrial process applications. The parameters to be measured (pH or ORP) are selected in the menu. The associated measured value can be displayed in the other measuring mode during measurement (for example pH can be switched to mV and mV/ORP can be switched to ORP %). The temperature is shown simultaneously and can be toggled between °C and °F or removed as required. Typically pH electrodes are always calibrated with the same pH values. The transmitter therefore provides the settings from the last calibration as a pre-selection for the next one. Should the buffer solutions be swapped by mistake during calibration, the plausibility check ensures that the calibration is accepted. Due to the large display the user guidance is simple and elegant. The correctness of the measurement result is of the highest priority. Different alarms are needed depending on the application. Therefore, the transmitter allows the configuration of the alarm contact, and the residual current, independently of one another and isolated for every possible fault. Unnecessary or undesired alarms can thus be removed. The two additional contacts can be used as limit contacts (and for temperature as well), as P(ID) controller and for electrode cleaning functions.