Dresser Masoneilan SVI II AP, Инструкция по эксплуатации

Страница: 93 / 160

DRAFT 6/8/10
81
SVI II AP Setups
Wiring an SVI II AP
q Cabling must be shielded to prevent electrical noise that would interfere with the
HART tones, with the shield grounded at only one location.
q Signal must be properly grounded in only one place.
NOTE
For details and calculation methods for wiring resistance, and
capacitance and for calculation of cable characteristics please
refer to the HART FSK Physical Layer Specification.
SVI II AP Setups
Control Systems using Explosion Proof or Conventional I/O Systems must have a
compliance voltage greater than 9 volts at 20 mA including wiring losses.
Typical Control Systems using Intrinsic Safety methods must have a compliance voltage
greater than 17.64 volts.
Typical system setups are shown in Figure 38 on page 82, for General Purpose and
Explosion Proof (EEx d) Installation Schematic and Figure 39 on page 83, for Intrinsically
Safe Installation Schematic. The SVI II AP positioner can be located in a general-purpose
or hazardous area protected by Explosion Proof (EEx d) methods. Wiring diagrams are
generalized, actual wiring must adhere to Electrical Installation section of manual and
local electrical codes. The use of a Handheld Communicator or a HART modem is not
permitted in the Hazardous Area protected by Explosion Proof (EEx d) methods. In
Figure 39 on page 83 the SVI II AP positioner is located in a hazardous area that is
protected by Intrinsically Safe wiring practices.
The SVI II AP requires an electrical input from a 4 - 20 mA current source. The SVI II AP
input signal can carry a HART communication protocol signal from ValVue software and a
HART modem, or from a HART Hand Held Communicator. Since the process control
system, the source of the input signal, is located in a non-hazardous location, setup
requires an intrinsic safety barrier be placed between the process control system and the
SVI II AP. If the SVI II AP is located in a hazardous area with Intrinsically Safe protection
a barrier is not required for a flameproof installation. Alternatively the system can be
installed as Explosion Proof ⁄ flameproof.
The SVI II AP can communicate with a remote PC running ValVue software via a modem
connected to the PC's serial port. The PC, which is not intrinsically safe, must be
connected to the circuit on the safe area side of the intrinsic safety barrier if the valve is
located in a hazardous area.
The SVI II AP can be operated, calibrated, configured, and interrogated either by using
local pushbutton and display, or by using a remote PC running ValVue software or with
the HART Hand-held Communicator. The HC375 HART Handheld Communicator is
approved for Intrinsically Safe use in accordance with FM, CSA, and ATEX standards.
Read and observe all HHC labelling. The SVI II AP is polarity sensitive so the positive
lead must be connected to the positive (+) terminal and the negative lead to the negative
(-) terminal. Reversal of input will not cause damage but the unit will not function.