How to Use the T8 Tensiometer with the Em50 Data Logger

1. Connection

The Em50 data logger uses the SDI-12 bus to communicate with the T8 Tensiometer. To connect the T8 to the Em50, an adapter cable with a stereo jack and an 8-pin female M12 connector is available from METER.

Wiring:

Em50 Connection:

The wiring diagram shows a comparison between a pigtail and a stereo connector. The stereo connector wiring is as follows:

Tip: Power (Red wire)
Ring: Ground (Bare wire)
Sleeve: Data (White wire)

Sensor Connector Wiring:

Signal	Color	Pin	Function
Vin	White	1	Power/DC+
GND	Brown	2	Ground
A-OUT+1	Grün (Green)	3	Analog output+ (pressure)
A-OUT-	Gelb (Yellow)	4	Analog ground
Digital OUT	Grau (Gray)	5	Status
RS485-A	Rosa (Pink)	6	RS485-A
RS485-B	Blau (Blue)	7	RS485-B
A-OUT+2/SDI12	Red	8	SDI12 (Data)

2. T8 Configuration Settings

To use the T8 with the Em50, certain default settings may need to be changed. If the T8 was shipped with the Em50, these settings are likely pre-configured. Use the tensioVIEW software (Version 1.30 or higher) and the tensioLINK USB converter to adjust the T8's settings. The T8 requires firmware version 3.0 or higher.

Access the settings by selecting 'Power' access mode. The following settings should be enabled ('on'):

SDI/SDI12 Interface: on
System/3V Supply: on

The configuration screen within the tensioLINK USB Adapter interface shows these settings. Specifically, under the 'Configuration' tab, the 'SDI12 interface on' option should be checked. The SDI12 sensor address and sync mode do not impact behavior as the Em50 powers the T8 on request and uses a broadcast address.

All other settings are not critical for Em50 usage.

3. Em50 Setup

The Em50 requires firmware version 2.23 or higher. Use the latest ECH20 utility for setup. Any of the Em50's five ports can be used to connect a T8. Within the ECH20 utility, select UMS T8 Tensiometer for the port connected to the T8. Performing a scan should then display water tension and temperature readings.

The ECH20 Utility interface allows for sensor configuration. For the Em50, the 'Port 1 Sensor' dropdown should be set to 'UMS T8 Tensiometer'. The 'Sensor Measurement' section shows the measurement interval and data storage status. The 'Em50 Port Scan' section displays the readings from the connected sensors, such as '-38.11 kPa, 23.7 °C' for the T8.