Instruction manual

46 RFT9739 Field-Mount Transmitter Instruction Manual
Output Wiring
continued
Figure 5-20c. Wiring to pressure transmitter — digital communications
5.8 Remote-zero switch
The transmitter can be configured to allow transmitter zeroing from an
external switch. The switch must be a momentary-type contact, normally
open, and must carry 1 mA of current in the closed position. The open
circuit voltage is 5 VDC.
Use terminals 21 and 16 for the remote switch. The remote-switch input,
frequency/pulse output, and control output share terminal 16 as a
common return. See
Figure 5-21
.
Section 6.4
, page 57, describes the flowmeter zeroing procedure.
Figure 5-21. Wiring to remote-zero switch
Pressure transmitter
SMART only (1150 or 3051)
WARNING: Pressure transmitter wiring is
not intrinsically safe
Power
supply
24 VDC
250 ohm ±5%, 0.5 W
250 ohm ±5%,
0.5 W
RFT9739
output terminals
Remote
switch
RFT9739
output terminals
ZERO+ (signal line)
RETURN (ground)