The pressure transmitters Series 26 Y are used in water level measurements that are price-sen
sitive but still require considerable accuracy.
Y-series transmitters have an extremely small temperature error. This is achieved by means of
digital compensation of an all-analogue signal path. The gain and the zero point of the gain circuit
can be influenced by digital/analogue converters. These receive their numerical values from an
EEPROM that is addressed depending on the temperature. A mathematical model for TC zero
and TC gain with any order can therefore be determined in the calibration process and stored in
the transmitter with a resolution of 1,5 K. The accuracy of the end product therefore essentially
depends on the amount of testing and the linearity of the measuring cell.
With the Series 26 Y, the monocrystalline silicon measuring cell is reliably protected from the
measuring medium by a stainless steel diaphragm. The steel diaphragm itself is protected from
mechanical influence by a plastic cap, and has outstanding performance features with regard to
accuracy and stability due to its large diameter of 17 mm
The Y-line transmitters have an extremely small temperature error. This is achieved using an additional circuit containing a temperature sensor that subdivides the temperature range into fields that are 1,5 Kelvin (K) wide. The TK zero and TK compensation values are calculated for each field and programmed into the additional circuit. During operation, these values are fed into the analogue signal path depending on the temperature. Each temperature is the „calibration temperature” for this transmitter. The accuracy thereof is mainly determined by linearity. 120 fields are available, representing a possible temperature range of 180 K. The wider the temperature range, the greater the amount of testing that is needed to minimise the inaccuracy of the mathematical model.