Watts HF scientific 28052, Owner'S And User'S Manual, Page: 23 / 67

Catalog No. 29290 16
Rev 3 06/2020
j. Make connections following all local, state, federal and other
governmental requirements, and all building and construction codes
and standards for all electrical connections.
Earth or Ground wire must be connected to a terminal on the
MTOL+ marked “G” .
k. A strain relief strap is provided to reduce tension on the power
terminals. Pull this tight after completing the connections.
l. Perform all checks necessary to confirm proper wiring and safe
electrical connection.
3.4.2 Terminal Block (P1) Connections:
Shut off and disconnect all electrical power BEFORE making
or changing any connections. The terminal block (P1) is
located close to the power connection.
The terminal block for RS-485 (Modbus), 4-20 mA and Alarms has spring
loaded connections.
To open the connection, insert a 3mm (1/8 in) flat blade screwdriver into
the slot right above the electrical connection. Pulling up slightly on the
screwdriver opens the terminal block connection. Removing the
screwdriver tightens the connection.
There are two stacked rows of connections which are labeled on the PCB.
The alarm connections are on the upper row. The RS-485 and 4-20mA
are on the lower row.
These connections are rated for a wire size from 12-28 AWG, either solid
or stranded.
a. Alarm and I/O Connections.
•
The Alarm 1 and Alarm 2 relays are mechanical relays rated at 120-240
VAC 2A.
•
Note that the relays are labeled NO (Normally Open), NC (Normally
Closed) and C (Common).
• The normal condition is with power applied to the MTOL+ and in a non-
alarm condition. Operation of these alarms is covered in section 4.2.4
Configuring the Alarms
.
•
Connections are labeled beneath the large terminal block. These
connections are on the upper row.