Digital Output Wiring; Setting Failsafe Direction And Write Protect Jumpers - Honeywell STT850 Quick Start Manual

Digital Output Wiring

Digital Output is available only on HART transmitters. The Digital Output should not use the
same power supply as used to support the 4-20mA transmitter output. See
Figure 14.
For Intrinsically Safe (IS) applications, the 4-20mA and the Digital Output must use
separate IS Barriers.
Figure 13: Digital Output Connections for mA Load (HART only)
For best performance, it is recommended that:
•
Digital Output wires should be in a separate shielded twisted pair cable, do
not use the same cable as used for the Loop or the Sensor wires
•
If using the same power supply to operate both the 4-20mA Loop and the
Digital Output, then make the interconnections to the power supply terminals
directly at the power supply
NOTE: Intrinsically Safe Installations require the use of separate IS Barriers for the
4-20mA output and for the Digital Output connections
Figure 14: Digital Output Connections for PLC Counting Input (HART
Set the Jumpers For HART/DE
Setting Failsafe Direction and Write
Protect Jumpers
The SmartLine Temperature Transmitter
(DE or HART) provides two jumpers to
set the desired failsafe action and Write
Protect option. See
Figure 15
The top jumper on the electronics
module sets the Failsafe direction. The
default setting is up-scale failsafe.
Up Scale drives the loop to a value
greater than 21mA while Down Scale
drives the loop to a value less than
3.8mA.
You can change the failsafe direction by
moving the Failsafe Jumper (top jumper)
to the desired position (UP or DOWN).
If your transmitter is operating in DE
mode, the upscale failsafe action will
cause the transmitter to generate a
"+ infinity" digital signal, while a
downscale failsafe will cause the
transmitter to generate a "– infinity"
digital signal.
The bottom jumper sets the Write
Protect. The default setting is OFF (Un-
protected).
When set to the On (Protected) position,
Changed configuration parameters
cannot be written to the transmitter.
When set to the OFF (Un-protected)
position, Changed configuration
parameters can be written to the
transmitter.
Figure 13
only)
ATTENTION: Electrostatic
Discharge (ESD) hazards. Observe
precautions for handling
electrostatic sensitive devices
Step Action
Turn OFF Transmitter power.
1
Loosen the end-cap lock, and
2
unscrew the end cap from the
Electronics side of the Transmitter
housing.
If there is a Display module,
3
carefully depress the tabs on the
sides of the Display Module and
pull it off.
If necessary, move the interface
connector from the Communication
Module. Do not discard connector
Set the Failsafe Jumper (top
4
jumper) to the desired action (UP
or DOWN). And the Write Protect
jumper (Bottom jumper) to the
desired behavior (Protected or
Unprotected) See Figure 16 for
jumper positioning.
If applicable, re-install the Display
5
module as follows:
• Orient the display as desired.
• Install the Interface Connector in
the Display module such that it will
mate with the socket for the display
in the Communication module.
• Carefully line up the display,
and snap it into place. Verify that
the two tabs on the sides of the
display latch.
Screw on the end cap and tighten
6
the end-cap lock. Turn ON
Transmitter power.
STT850/750 Quick Start Guide
Explosion-Proof Conduit Seal
and
When installed as explosion proof in a Division 1 Hazardous Location, keep
covers tight while the Transmitter is energized. Disconnect power to the
Transmitter in the non-hazardous area prior to removing end caps for service.
When installed as non-incendive equipment in a Division 2 hazardous location,
disconnect power to the Transmitter in the non-hazardous area, or determine that the
location is non-hazardous before disconnecting or connecting the Transmitter wires.
Transmitters installed as explosion proof in Class I, Division 1, Group A Hazardous
(classified) locations in accordance with ANSI/NFPA 70, the US National Electrical
Code, require a LISTED explosion proof seal to be installed in the conduit, within 18
inches (457.2 mm) of the Transmitter. Crouse-Hinds type EYS/EYD or EYSX/EYDX are
examples of LISTED explosion proof seals that meet this requirement. Transmitters
installed as explosion proof in Class I, Division 1, Group B, C or D hazardous
(classified) locations do not require that explosion proof seal be installed in the conduit.
Step
1
See Figure 8,
using a 1.5 mm Allen wrench.
Remove the end cap cover from the terminal block end of the
2
Electronics Housing
3
Feed loop power leads through one end of the conduit entrances on
either side of the Electronics Housing. The Transmitter accepts up to
16 AWG wire.
Connect the positive loop power lead to the positive (+) terminal and
4
the negative loop power lead to the negative (-) terminal. Note that
the Transmitter is not polarity-sensitive.
Shielded, twisted-pair cable such as Belden 9318 or equivalent must
be used for all signal/power wiring.
Note: If solid core wire is used strip insulation 1/4 in (6 mm). Once
inserted under the square washer the stripped portion should be
contained under the square washer. If multi-stranded wire is used, a
ferrule is to be used and the stripped wire should be in the insulated
portion of the ferrule. The ferrule can be also be used on the solid
core wire.
After wiring the Transmitter as outline in the next sections, torque the
screws to 1.1 Nm (10 lb-in)
5
Feed input sensor wires through the 2
connect wire per wiring diagrams
6
Replace the end cap, and secure it in place
Configuration Guide
This transmitter comes with a standard factory configuration. Consult the nameplate for
basic information.
Reconfiguration for your particular application can be accomplished by following
instructions in the Transmitter User's manual.
This can be found by following the website URL or QR code on page 1 of this
document.
Figure 15: Jumper Location HART/DE
Jumper Settings
Action
above, for parts locations. Loosen the end cap lock
nd
conduit entrance and
Description
Failsafe = UP (High)
Write Protect = OFF (Not Protected)
Failsafe = DOWN (Low)
Write Protect = OFF (Not Protected)
Failsafe = UP (High)
Write Protect = ON (Protected)
Failsafe = DOWN (Low)
Write Protect = ON (Protected)
Figure 16: Jumper Settings
4