Dynisco PT460DN, Operating Manual

Page: 5 / 42

5
GENERAL
the high process temperatures.
The lower diaphragm is the surface in contact with the media being measured. This diaphragm can be
made from a choice of materials. The standard material is heat-treated 15-5 stainless steel with DyMaxTM
coating. This has average corrosion and excellent abrasion resistance and is similar to 17-4 stainless
steel. Other materials are also available such as Hastelloy C-276 which has excellent corrosion resistant
properties (but is not good for abrasion). For other materials please consult the factory.
Behind the lower diaphragm is a capillary tube filled to the upper diaphragm. As the process pressure
deflects the lower diaphragm, the fill is displaced through the capillary tube to deflect the upper
diaphragm.
The upper diaphragm has a strain gage element in the configuration of a Wheatstone Bridge. The
deflection of the upper diaphragm causes a change in the resistance of the strain gage and hence a
change in the balance of the bridge. The amount of imbalance is directly proportional to the applied
pressure. This completes the translation of pressure applied to the lower diaphragm into a usable
electrical signal.
Fig. 1-1 Fig. 1-1
Fig. 1-1 Fig. 1-1 Fig. 1-1 Functioning Principle of the Dynisco Filled Assembly
Functioning Principle of the Dynisco Filled Assembly
Functioning Principle of the Dynisco Filled Assembly Functioning Principle of the Dynisco Filled Assembly Functioning Principle of the Dynisco Filled Assembly
The low level output signal from the bridge is amplified via an instrumentation amp circuit. The amplified
signal then goes to the input of the analog-to-digital (A/D) converter.
1. 1. 1. 1. 1.7 7 7 7 7 D D D D D
EVIC EVIC
EVIC EVIC
EVICE E
E E
E
N N N N N
ET ET
ET ET
ET
F F F F F
EA EA
EA EA
EATURE TURE
TURE TURE
TURES S
S S
S
The PT4xxDN utilizes the DeviceNet Predefined Master Slave Connection Set operating as a Group 2 Only
Server. The PT4xxDN supports baud rates of 125K, 250k, and 500k. The node address can be set to any
address between 0 and 63. The default baud rate and node address are 125k and 63, respectively.
Pressure, alarm, and status data are available via polled I/O messages. Alarm, Warning and Scaling
parameters are configured using Explicit messages.
Filling opening
Strain gage
on the
measuring
diaphragm
Capillary with pressure
transmission fluid (Hg)
Total filling
volume = 7mm
3
Separating
diaphragm
0.15mm thick
Base of electronics housing