Micro Motion RFT9709 Instrukcja Obsługi Pobierz pdf (Strona 138)

124

Using ProLink

Software with Micro Motion

Transmitters

Configure Menu: Transmitter Information

continued

Burst control for RFT9739 and RFT9712/RFT9729

Modbus pressure compensation

The Modbus-compatible host controller downloads pressure values to

the RFT9739 by writing an integer that represents gauge pressure to

input register 40007, or by writing an IEEE 754 floating point value that

represents pressure to register pair 20257-20258.

The user must configure the RFT9739 for pressure compensation, as

described in

Section 8.7

, page 86.

Control output

The RFT9739 control output can be configured to indicate pressure

input failure. In this configuration, if an input failure is indicated, one of

the following has occurred:

• The mA or digital input from the pressure transmitter is out of range

(less than 2 mA or greater than 22 mA).

• The pressure device failed to respond to a HART command.

11.4 Burst control for RFT9739

and RFT9712/RFT9729

Use the Burst option buttons to determine whether the RFT9739,

RFT9712, or RFT9729 will communicate in burst mode under HART

protocol. The IFT9701 and IFT9703 do not support burst mode data

transmission.

Before switching burst mode ON, configure the transmitter to use HART

protocol (see the transmitter instruction manual), then use a Model 275

HART Communicator or AMS with the transmitter to configure the burst

mode.

If ON is chosen, the transmitter bursts data at regular intervals via the

fixed 4 mA or RS-485 wiring loop. The interval varies according to the

baud rate. At 1200 baud, the host receives two updates every 3.7

seconds.

• The RFT9739 can burst HART commands 1, 2, 3, 33, and 110. The

default command after a master reset is 2.

• The RFT9712 and RFT9729 can burst HART commands 1, 2, 3, and

110. The default command after a master reset is 1.

• HART commands are listed in

Table 11-2

• On a multidrop network, only one transmitter at a time may be in

burst mode. Burst mode can be enabled regardless of the transmitter

address.

• When using the Bell 202 standard, the transmitter primary variable

milliamp output will become fixed if the transmitter has an address

other than zero (0).

For RFT9712 and RFT9729 transmitters, when the display is opened,

neither button will be selected, as shown in

Figure 11-3

, because the

ProLink software cannot predetermine the RFT9712 or RFT9729 burst

state.

1 2 ... 133 134 135 136 137 138 139 140 141 142 143 ... 213 214

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