Instruction manual

Getting Started
continued
RFT9739 Field-Mount Transmitter Instruction Manual 9
Output Wiring Startup TroubleshootingBefore You Begin Getting Started Mounting
Power-Supply and
Sensor Wiring
Communication settings
Switch 5 enables the user to choose the standard communication
configuration or user-defined parameters. With switch 10 in the ON
(CONFIG) position, switches 1 through 6 can be used for setting user-
defined communication parameters.
Standard communication setting
To use the standard communication configuration, set switch 5 to the
STD COMM position. Setting the switch in this position establishes the
following communication parameters:
• HART protocol on the Bell 202 standard, at 1200 baud, on the primary
mA output
• Modbus protocol in RTU mode, at 9600 baud, on the RS-485 output
• 1 stop bit, odd parity
For RFT9739 software versions 3.6 and later, if switch 5 is in the STD
COMM position, and the RFT9739 has a display, an error message will
appear on the display when an attempt is made to change the
communication configuration using the RFT9739 display controls.
User-defined communication settings
To establish user-defined settings, set switches as instructed in
Table 2-2
, page 10. With switches 1 through 6, the user can set baud
rate; stop bits and parity; data bits, protocol, and physical layer. The
default settings are HART protocol, over RS-485, at 1200 baud, with
1 stop bit and odd parity.
Milliamp output scaling
Switches 7, 8, and 9 allow the user to choose 0-20 mA or 4-20 mA
scaling for mA outputs, and upscale or downscale fault outputs.
Switch 7 defines the primary mA output scaling. Switch 8 defines the
secondary mA output scaling. Either switch may be set in the 0-20
position or the 4-20 position.
• The mA outputs are NAMUR compliant when switches 7 and 8 are in
the 4-20 position. See
Section 5.3
, page 27.
• Communication using the HART protocol over the primary mA output
requires switch 7 to be set in the 4-20 position.
• If switch 7 is in the 0-20 mA position, communication may be lost if
output is less than 2 mA. To re-establish communication, move switch 7
to the 4-20 mA position.
Switch 9 defines the RFT9739 fault outputs. Fault outputs can be set for
downscale or upscale levels.
• If switch 9 is set to the DWNSCALE position, mA outputs go to 0 mA if
they produce a 0-20 mA current, or to 0-2 mA if they produce a
4-20 mA current; the frequency/pulse output goes to 0 Hz.
• If switch 9 is set to the UPSCALE position, mA outputs go to 22-24 mA;
the frequency/pulse output goes to 15-19 kHz.
• For more information, see "Fault outputs," page 65.