6
Installation and Operating Manual
IP227, Rev DA
Mobrey MCU200 Series
February 2020
2.5
Extension cables
Extension cables up to 50 metres long can be fitted to most Mobrey ultrasonic sensors in the
factory to special order, but a better site arrangement is to have a separate extension cable.
When a double coaxial cable needs to be extended, two sets of coaxial plugs and sockets will be
needed; one set for transmit, and one receive. Care must be taken that the connectors are not
earthed, or shorted together in any way, to prevent cross-talk or pick-up. The coaxial
connections must be made in a waterproof junction box. Terminal blocks should not be used.
The extension cable needs to be of 50ohm characteristic impedance. Suitable dual coaxial
extension cables can be purchased from Delta Mobrey (Part No. K178).
For extensions over 50 metres, it is recommended that two runs of single coaxial low-loss cable
is used, with the transmit and return cable runs separated by 0.15 metres to minimise
cross-talk. If several sensor cables are being run together then all the transmit cables (those
connected to E2) should be grouped together and all receive cables (those connected to 1E)
grouped together maintaining the separation specified above.
3.
Control unit installation
3.1
Safety matters
Review the safety information provided at the beginning of this user manual.
3.2
Mechanics
The control unit is supplied with three holes drilled in the bottom (longer) side of the box.
Two glands are supplied for the power input cable and relay output cable. The sensor is normally
supplied fitted with a suitable gland on the cable. Two further holes can be drilled in the bottom
side of the box should these be needed: it is recommended that the circuit board is removed
whilst drilling extra gland holes.
Determine suitable mounting location with regards to:
Surface composition / load bearing capacity
Cable length restrictions
Accessibility for servicing
All cable connections are made to the terminal blocks along the bottom edge of the PCB (see
fig.5). Release the terminal screw before inserting the wire.
