Brooks Ar-Mite MT3750, Installation & Operation Manual

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Section 2 Installation
Brooks
®
Ar-Mite
TM
MT3750C
19
For electrical hook-up of units requiring intrinsically safe power
connections, use Brooks optional power supply and relay connected as
in Figure 2-6 for the integral alarm.
Installation of Transmitter
A. For intrinsically safe operation (recognized by a BLUE COVER),
intrinsic safety barrier selection, cable parameters and power supply
limits must be in accordance with the entity parameters shown in
Figure 2-6. Do not connect the zero wire (keep it floating) when the
transmitter is in normal operation. The zero wire is not meant to be
extended as zeroing must be done locally.
B. If the area classification is Division 2 and Zone 2, a barrier is not
required and cable parameters are not applicable. The electrical code
will require the use of conduit for wire protection. Refer to Figure 2-7.
C. If the installation is to be protected by Division 1 and Zone 1 explosion-
proof methods, explosion-proof installation methods must be followed.
Refer to Figure 2-8.
D. The power supply voltage determines the maximum resistance of the
loop, the associated cable and the barrier. Always be sure that the
voltage on the transmitter is within the specifications.
E. After installation and powering of the loop, the transmitter must be
zeroed to compensate for any stray magnetic effects in the vicinity
of the transmitter. The zero function may be activated as part of a
periodical maintenance check. The zero function is activated by
momentary (>2 seconds) shorting the zero wire to the ground wire
while power is on. Connect the transmitter as shown in Figure 2-9.