Siemens SITRANS DA400 Operating Instructions Manual page 16

Assembly
4.2 Mounting
The position of the mounting holes and the mounting dimensions in millimeters are indicated
on the rear of the housing.
The device should preferably be mounted vertically with the cable gland pointing downwards.
Mounting the sensor
Each acoustic sensor should be individually mounted on the outside of the pump or valve
housing, close to the valve to be monitored, using the enclosed M6 hexagon socket screw
and positioning pin.
There is a good acoustic coupling if no elastic elements such as seals or similar are located
between the sensor and the valve, i.e. there are good metallic connections.
As the structure-borne sound is injected into the sensors via their base, the substrate on the
housing must be uniformly even and smooth, and at least as large as the sensor base. To
improve the coupling, in certain circumstances a viscous lubricant can be used (not
included).
Note
Mounting the sensor
On pumps that have good acoustic coupling between the delivery and intake side, it can be
sufficient to use just one sensor for a pump head (with two valves). However, in this case it is
not possible to distinguish which valve has a leak.
The acoustic sensors are mounted at an equal spacing to the valves.
4-2
SITRANS DA400 with protection against explosion
Operating Instructions, 02/2006, A5E00684661-01