2.Control Unit Installation
2.1 Mechanical
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.
Fig. 4 MCU200 housing dimensions
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.
2.2 External Connections
Protection for permanently installed equipment
NOTE: This equipment is regarded as permanently installed equipment and must be wired up using suitable cable for the current and voltage specified. A suitable switch or circuit breaker must be included in the installation and this should be in close proximity to the equipment and marked as its disconnecting device. A suitable fuse rated at 3A must be fitted in the supply. Each relay circuit must be protected by a fuse not exceeding the maximum rated current for the relay as specified in the manual.
Fig 3 Suitable extension cables
50mtr | over 100m | |
RG174 | URM76 | Consult |
RG178 | RG58 | factory |
|
|
|
Two cables are required per sensor. The RG178 should be used where the cable itself is subject to temperatures exceeding 74°C.
(i)AC Mains is connected between the “N” terminal for neutral and one of the “115V” or “230V” terminals depending on the voltage supply available - BEWARE - the terminal not connected externally will be “live” once the transformer is powered via the other terminals.
(ii)Protective earth
NOTE: A protective earth should be used for all applications
(iii)The DPCO relay has two sets of contacts. These are labelled:
Set 1: | NC1 | - Normally closed |
C1 | - Common | |
NO1 | - Normally open | |
Set 2: | NC2 | - Normally closed |
C2 | - Common | |
NO2 | - Normally open | |
Relay warning
CAUTION: External circuits (such as signal circuits) with accessible parts or basic insulation only, MUST NOT be connected to the relay if the relay is also connected to external circuits which are hazardous live (mains circuits).
(iv)The Sensor connections are labelled “1”, “E” for the receiver crystal and “2”, “E” for the coax cable to the transmitter crystal. The screens of these coax cables are connected to the terminals marked “E”.
(v)The Auxiliary Input is a terminal which can be connected to a “push to reset” button to achieve a latching alarm, or to another Mobrey control unit, to give a pump control from the MCU200 unit relay output. If a short circuit is connected between terminals 3 & 4, the MCU200 relay, once de- energised, is held
Fig. 5
MCU201 PC Board