User guide

Instruction Manual HYDACLab



03.03.2008

4.2 Analogue Output

Analogue output signals representing measured values are output sequentially to Pin 4, when

synchronization with the controller interfaced to the sensor is required.

The sequencing of the signals involved is as shown in the diagram below:

All signals output to the analog output are 4 .. 20 mA current-loop signals, sequenced

and spaced as follows

Output signal Duration

Start signal: 20 mA 2 s

______________________________________________ Pause (4 mA) 2 s

Signal 1: Relative change in viscosity -30% ... +30% 2 s

Pause (4 mA) 2 s

Signal 2: Relative change in dielectric constant -30% ... +30% 2 s

Pause (4 mA) 2 s

Signal 3: Relative humidity 0% ... +100% 2 s

Pause (4 mA) 2 s

Signal 4: Temperature -25°C... +100°C 2 s

Pause (4 mA) 2 s

Signal 5: Status signal See table below for levels 2 s

Pause before next output cycle: 4 mA 30 s

Explanation of status signal:

Status Status signal

(mA)

Referencing phase 5

Operating phase 7

Fluid condition out

of range

9 or 11

Internal error

 13

Note: Due to possible tolerances, we recommend setting the threshold in the evaluation electronics approx. 0.25 mA below the

ideal value given in the table.

Start

Rel.

visc.

Rel.

humidity

Temp.

Status

Start

20mA

4mA

30s