WTS-AM-1E Wireless Strain Bridge Transmitter Module

Connector Pin Diagram

Connections

WTS-AM-1E-OEM-EA, WTS-AM-1E-OEM-IA

Power

Attach power supply wiring to the module as shown below:

Connect to a 3 Volt power supply or batteries.

This module is not reverse polarity protected!

The maximum voltage is 3.6 V!

For battery information please refer to Appendix D – Battery Selection in the WTS Telemetry User Manual.

Sensor

Strain gauge connection is 4 wire as follows:

The resistance of the strain gauge can be between 85 and 5000 ohms. The WTS-AM-1E-OEM can support up to four 350 ohm strain gauges bridges attached in parallel (At the expense of reduced battery life).

The cable lengths between the WTS-AM-1E-OEM and the gauges should be kept below three metres and generally as short as possible. As the measurement is four wire then as the cable length increases the voltage drops in the cable will have more of an effect on the factory mV/V calibration.

The strain gauge measurement is bi-directional, i.e. tension & compression.

WTS-AM-1E-D

Power

Power can be supplied by fitting two ‘D’ cell alkaline 1.5 V batteries or the module can be supplied from an external 5 Vdc to 18 Vdc source.

In both cases you need to fit the JP1 power jumper to supply power to the transmitter module. When powered from the external DC source the LED will illuminate.

For battery information please refer to Appendix D – Battery Selection in the WTS Telemetry User Manual.

Sensor

The strain gauge input is connected to the module via a 2 part screw terminal block.

WTS-AM-1E

Power

The enclosure is designed to accept two AA batteries. Maximum voltage 1.8 V per cell.

For battery information please refer to Appendix D – Battery Selection in the WTS Telemetry User Manual.

Sensor

The input connections are accessed by lifting the right hand cover plate, this plate incorporates the WTSATNA Antenna; take extra care when re-assembling that the grey UHF cable is attached to the antenna socket.

WTS-AM-4

Power

Power is supplied by connecting a 3 V supply to the terminals as shown below:

Connect to a 3 Volt power supply or batteries.

There is no reverse polarity protection!

Connecting WTS-BB1

Power to transmitter modules in this enclosure can also be supplied by a WTS-BB1 battery box which contains two AA 1.5 V batteries.

Connect to a 3 Volt power supply or batteries.

For battery information please refer to Appendix D – Battery Selection in the WTS Telemetry User Manual.

Sensor

Using Completion Resistors

The WTS-AM-4 has the option for users to add up to three completion resistors, these can be used to enable the WTS-AM-4 to accept half and quarter bridge strain input when a strain transmitter module is fitted. The three completion resistors are located as shown below:

If using a half bridge only R1 and R2 need to be fitted, we recommend low drift precision resistors to ensure reading stability typically 0.1% 5ppm/oC. If using a quarter bridge R1, R2 and R3 must be fitted, R3 must be the same resistance as the single gauge being used in the quarter bridge. The diagram below shows how you should wire for full, half and quarter bridge configurations.

Full Bridge

Half Bridge

Quarter Bridge

Strain Element in Compression

Strain Element in Tension

Shield Connections (All Enclosures)

We recommend the following rules to determine whether there should be a connection between the transmitter module shield and the sensor chassis or cable:

1. If the sensor is remote to the transmitter module and the screen of the signal cable is NOT connected to the sensor chassis then the cable screen should be connected to the transmitter module shield connection.
2. If the sensor is remote to the transmitter module and the screen of the signal cable IS connected to the sensor chassis then the cable screen should be NOT connected to the transmitter module shield connection.
3. If the transmitter module is integral to the sensor or mounted very close and the module is mounted on a metal chassis then the answer to whether the transmitter module shield connection should be connected to the metal chassis is a matter of experimentation. This connection must be as short as possible. The T24 Toolkit can be used to chart the signal levels and tests should be undertaken to determine whether there is a better radio signal with or without the shield/chassis connection. The quality of the measured reading should also be looked at. In cases where the shield/chassis connection makes no difference to the radio signal or the reading quality then the connection should be made.

For more information visit Electrical Wiring Diagrams