YOKOGAWA DPharp EJXC40A, Руководство пользователя

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<7. HART Communication>
7-9
IM 01C25W05-01EN
NOTE
The damping time constant set here is only for
the pressure transmission part.
The damping time constant for the differential
pressure(DP) is the sum of the damping
time constants for the differential pressure
transmission part, pressure transmission part,
and the capsule assembly.
The diagram in subsection 7.2.2.6 shows the
relationship of each part. Upon shipment from
the factory, the differential pressure is assigned
to PV which shall be output via 4 to 20 mA. To
change the assignment of PV, refer to subsection
7.2.2.2. To change the damping time constant
for the differential pressure, refer to subsection
7.2.2.6. Refer to GS(General Specifications)
or User’s Manual of each transmitter for the
damping time constant of capsule assembly.
7.2.3.3 Impulse Line Connection
Orientation Setup
This parameter allows the impulse line connections
to be reversed. This function is used when the
low pressure side and high pressure side line
connections are reversed when the digital remote
sensor transmitter is installed.
To change the impulse line connection direction
of the digital remote sensor transmitter, follow the
procedure below.
• Recalling and setting Pres 1/2 Swap parameters
Recall
parameters
[Root menu] → Detailed setup →
Signal condition →
Pres 1/2 Swap Select Normal or Reverse.
7.2.3.4 Bi-directional Flow Measurement
Setup
This parameter enables output whose positive and
negative outputs and displays are symmetrical
about the low limit set at the center of the
measuring range. This is used to measure both
the forward and reverse flow rates using the digital
remote sensor transmitter with the output for 0%
input set to 50% (12mA).
To set the bi-directional flow measurement, follow
the procedure below.
• Recalling bi-directional flow mode (Bi-dir mode)
parameters
Recall
parameters
[Root menu] → Detailed setup →
Signal condition →
Bi-dir mode Select On or Off.
Set the Bi-dir mode parameter to On.
The factory default setting is Off.
Example: If the bi-directional flow measurement is
enabled for the measurement range of 0 to 10
kPa, the measuring range is changed to –10 to
0 to 10 kPa (output 0 to 50 to 100%). However,
the LRV and URV values are not changed.
• Combining this with square root output mode
provides a square root output computed
independently for 0% to 50% output and for
50% to 100% output.
• The low cut function works symmetrically on
the positive and negative sides with the 0%
point at the center.
20mA (100% display)
4 mA (−100% display)
Output mode “Linear”
LRV URV
F0705.ai
20mA (100% display)
Low cut
4 mA (−100% display)
Output mode “Square root”
LRV URV
Figure 7.2.2 Bi-directional Flow Measurement Setup