The DMT152 transmitters are designed to operate with a supply voltage of 15 … 28 VDC (voltage output version) or 21 … 28 VDC (current output version). When only the RS-485 output is used, 11 … 28 VDC is enough in typical measurement conditions.
When measuring in pressures 20 … 50 bara (290 … 725 psia) or in temperatures −40 … 0 °C (−40 … 32 °F), a supply voltage of 21 … 28 VDC is required.
The power supply should maintain the voltage for all load conditions. Voltage fluctuations must be smaller than 0.3 V, as continuous supply voltage fluctuation may interfere with the auto-calibration function.
- If auto-calibration has failed due to voltage fluctuation, you can verify it using the STAT command on the serial line. See Show transmitter status.
- If auto-calibration fails repeatedly, the Autocal error code will be activated. See Error codes.
Current consumption during normal operation is 20 mA. Consumption increases during auto-calibration and sensor purge. The maximum current consumption is 220 mA pulsed current.
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DMT152 can be powered by the MI70 indicator or the Vaisala USB cable. However, the power supplied by these devices may not be enough for all functions of the transmitter (for example, the current output). If you are using a separate power supply in connector I, connect the power supply first before connecting the USB cable or the MI70 indicator. The order is important, since the transmitter will use the power supply that is connected first. |