Brooks Instrument MT3809G - Manual (Page 36)

2-6
Installation and Operation Manual
X-VA-MT3809G-MT3810G-eng
Part Number: 541B182AAG
September, 2013
Models MT3809G & MT3810G
Section 2 Installation
6. After installation and powering of the loop, the transmitter must be
zeroed, both electrically and mechanically. This operation will compensate
for any stray magnetic effects in the vicinity of the transmitter. Flow must
be verified to be zero when the zero function is momentarily activated.
Note: The zero adjusting of the pointer influences the transmitter
indication, but not the other way around. Therefore, first adjust the pointer
at the zero flow position, then the transmitter must be zeroed.
With the float at the zero flow position and the pointer at the zero position,
set zero flow by either shorting the two pins together at the terminal block.
If desired, a zero switch can be remotely mounted and wired to these
terminals. The hazardous area classification will determine the wiring
methods used for this switch.
The pointer must also be adjusted to the reference line on the scale using
the adjustment screw on the face of the pointer, next to the hub. The zero
function may be activated as part of a periodical maintenance check.
7. Under actual flow conditions, verify that the transmitter output matches
the mechanical pointer position. If a discrepancy is noted, the HART
communications channel can be used to verify or adjust the transmitter
settings.
d. Microprocessor transmitter with alarm and pulse output wiring
connections
All internal parameters can be accessed over the HART communications
channel, including the configuration of the output signals used for alarms
and pulse output. An external termination box is attached for easy hook-up
of these signals. The alarms are configurable as normally open or normally
closed.
The alarm contact and pulse output digital signals are electrically identical,
independent, optically coupled transistor outputs. Wiring will be as required
by the external driven system - Prover, DCS/PLC, terminal-automation
system, batch controller etc. These can be wired as an open collector or
open emitter signal on the high or low side of voltage-rail within the
receiving equipment, depending upon the signal needs. When interfacing
to external electronics, be careful to work within the voltage/current polarity
and limits as specified in Section 1.
To install the typical transmitter alarms and/or pulse digital outputs
configuration:
1. Intrinsically safe installations require the use of barriers, power supply
limits and cable parameters as shown in the installation diagram. All
connections are made in the transmitter housing. Refer to Figures 1-4 and
1-8.
Note: To ensure full EMC protection the ferrite core included with the meter must
be installed to the input power I/O cable at the supply end of cable.
2. If the area classification is Division 2, barriers are not required and cable
parameters are not applicable. However, the electrical code will require the
use of conduit for wire protection. Refer to Figures 1-4 and 1-8.
3. For flameproof installation the optional explosion proof enclosure is
required and explosion proof installation methods must be followed.
Refer to Figure 1-6.