Meriam M1500 Digital Pressure Transmitter - Manual (Page 10)

6
Pressure Connections Pressure Connections Pressure Connections Pressure Connections
Failure to keep pressure below specified limits could result in death or serious injury. See section
– Specifications of this manual.
All pressure connections are 1/8" NPT (female). A wrench should be used on the flats of the
pressure manifold to hold it securely and prevent accidental damage when installing or removing a
pressure fitting. Use suitable thread tape or thread sealing compound for leak-free connections.
3-valve equalizing manifolds are recommended for differential pressure units to prevent accidental
damage while installing or commissioning M1500-DN and -D
I transmitters and to support zeroing
procedures. See the Specifications section of this manual for pressure limit information on differential and other
pressure types. See the Zeroing section for information on zeroing the M1500.
Single Pressure Sensor Models Single Pressure Sensor Models Single Pressure Sensor Models Single Pressure Sensor Models
Single pressure sensors are available in all M1500 pressure and output types.
Differential pressure types, DN and D
I models, have two pressure ports in the 316L SS manifold. The ports are
engraved P1 (HI connection) and P2 (LO connection). Connect the application high pressure to the P1 port and the
low pressure to the P2 port for differential applications. For Vacuum applications using differential models, vent the P1
port to atmosphere and connect the vacuum line to the P2 port. Note that the output of the M1500 in this vacuum
configuration will transmit “positive” values. The receiving device will need to be configured to add the negative sign (
- ) to the received value.
D
I models are available with optional flushing ports to allow flushing the manifold interior (see graphic at right above).
This is desirable for dirty liquids, liquids with particulates or suspended solids, or congealing liquids. Use solvents
compatible with 316SS and Viton only.
Spray hazard. Wear approved safety glasses and impermeable gloves. DO NOT pressurize the
system; failure to follow these instructions could result in death or serious injury.
The flushing ports, an available option on D
I models, are linked by internal passages to their respective P1 or
P2 port. If a cleaning solvent is injected into one port it will flow through the manifold and the solvent will exit
from the connected port. DO NOT pressurize the cleaning solvent as spray or stream flow could occur. Meriam
recommends using a solution recovery system to capture the used cleaning solution. See the Specification section of
this manual for fitting details and wetted parts material. Refer to the solvent manufacturer’s Material Safety Data
Sheet for safe handling information.
Gauge, Compound and Absolute pressure types in single sensor M1500 Digital Transmitters use the pressure port
marked P1 on the manifold. Gauge pressure measurements are referenced to atmospheric pressure inside the
enclosure and measure from 0 to the full scale range. Compound units are gauge units that measure down to full
vacuum (approximately -14.7 PSIG) as well as up to the positive full scale range. Absolute pressure measurements
are internally referenced to a complete vacuum on the P2 side of the pressure sensor. See drawing below.
DN & D I Standard Manifold
P1 = HI, P2 = LO
D I Optional Flushing Manifold
P1 = HI, P2 = LO