Parameter Definition 1 aout1, North-South, x component aout2, West-East, y component Typically, only the component xis used. 2 aout1, wind speed aout2, wind speed alarm A digital output hi when wind speed > aout2_0 The following table shows the relationship between polar representation and the x and y vector components. Table 23 Windy and x components at Different Wind Direction Angles Wind Speed Wind Direction x Component y Component 1 0 -1 0 1 90 0 -1 1 180 1 0 1 270 0 1 188.8.131.52 Tunnel Application In the tunnel application, airflow can be presented with one mA output channel, because airflow goes along the tunnel. Typically, a relatively long average time (time constant) for wind speed parameter is applied. The sensor must be installed in a tunnel so that the sensor’s North is aligned with the tunnel. The Aout1 channel (x component) provides the airflow in the tunnel. The following figure shows atypical WMT700 installation in a tunnel. WMT700 User Guide M211095EN-H 66
Figure 25 WMT700 in Tunnels The following figure shows the 4…20 mA output as a function of airflow. The zero value is in the middle of the output scale (12 mA). When airflow increases from 0 ms towards North, mA output reduces from 12 mA linearly resulting in 4 mA with 20 ms wind. Similarly, when airflow increases from 0 ms towards South, mA output increases from 12 mA linearly resulting in 20 mA with 20 ms wind. Figure 26 mA Output in Tunnels Chapter 4 – Installation 67
The parameter aout_map with setting 1 is used to get the North-South component of winds aout_map,1 The North-South component to Aout1, the current output, -20 ... ms to 4 … 20mA, Aout2 disabled: s aout1_g,0.0004 s aout1_o,0.012 s aout1maxv,0.020 s aout1minv,0.004 s aout1mode,0 s aout1err ,0.002 s aout2mode,7 184.108.40.206 Crane Application In the crane application, WMT700 can provide wind speed value and to drive alarm signals with 2 mA output channels. The WMT00 alarm output signal can be connected to external audible or visible devices to trigger wind speed alarm for user-defined limits. Two analog channels are required for this application: • Channel 1 provides the wind speed value • Channel 2 provides the alarm signal Figure 27 Analog Output for Wind Speed and Wind Speed Alarm The wind speed value can be scaled according to the sensor’s measurement range. The alarm signal operates with on/off-mode. The alarm threshold can be adjusted. The following figure shows the relation of outputs. WMT700 User Guide M211095EN-H 68
Figure 28 mA Output in Cranes The aout_map with setting 2 is forgetting the wind speed value and the alarm signal. The wind speed value in the Aout1 channel activates the wind speed alarm when the wind speed value exceeds the set limit values aout_map,2 The analog output 2 works as digital output. aout2_o sets the threshold wind speed ( ws_tresh, unit ms) to 20 m/s: s aout2_o,20 s aout2_g,1 To invert the logic signal, types aout2_g,-1. aout1 gives wind speed 4 … 20 mA output. aout2 gives 0 mA when the wind speed is < 20m/s, otherwise 20 mA. Chapter 4 – Installation 69
s aout_map,2 s aout1_g,0.000044444 s aout1_o,0.004 s aout1maxv,0.020 s aout1minv,0.004 s aout1mode,0 s aout1err s aout2_g,1 s aout2_o,20 s aout2maxv,0.020 s aout2minv,0.000 s aout2mode,4 s aout2err ,0.00 4.8 Installing Bird Cage Install the birdcage on top of the wind sensor. In cold climates, take into account that accumulated snow or ice on the birdcage can disturb the measurement. In such conditions, visit the site frequently to clear ice and snow build-up. Make sure that you do not damage the WMT700 array when installing the bird cage. CAUTION! WMT700 User Guide M211095EN-H 70
Figure 29 WMT700 Bird Cage and Bird Cage Straps 1 Bird cage 2 Bird cage straps 3 Wind sensor 4 Guide for attaching the straps 5 Latch for attaching the straps. Unpack the birdcage and the straps. Position the birdcage on top of the wind sensor and press the kit down until the three hooks are in contact with the transducer arms. Run the lower strap through the three guides in the kit. Lift the latch screw, insert the strap to the latch, and press down the latch screw. To tighten the screw, turn it clockwise with a screwdriver or a socket. Do not over- tighten. Run the upper strap through the three guides in the kit, and repeat step 4 and step for it Installing Bird Net In areas with large populations of small birds, you can install a bird net over the birdcage. Cover the birdcage with the bird net. Tighten the bird net with cable ties. Chapter 4 – Installation 71
3. Cutoff the excess net below the cable ties. Bird net Wiring The pin M male connector is located at the bottom of WMT700. The connector is used for power supply, digital communications, and analog outputs. The signals related to digital communications are galvanically separated from the ground. The connector type is Hummel 7.106 series.