PD6870 Explosion-Proof Loop-Powered Process Meter
Instruction Manual
8
Cover Jam Screw
The cover jam screw should be properly installed
once the meter has been wired and tested in a safe
environment. The cover jam screw is intended to
prevent the removal of the meter cover in a flame-
proof environment without the use of tools. Using a
M2 hex wrench, turn the screw clockwise until the
screw contacts the meter. Turn the screw an
additional 1/4 to 1/2 turn to secure the cover.
Caution: Excess torque may damage the threads
and/or wrench.
Connections
To access the wiring connections, remove the enclo-
sure cover and unscrew the two captive screws that
fasten the display module. Signal connections are
made to a three-terminal connector on the rear of the
display module. Grounding connections are made to
the two ground screws provided on the base – one in-
ternal and one external.
S+
4-20 mA signal positive terminal
connection
S-
4-20 mA signal return/negative terminal
connection
B-
4-20 mA signal return/negative terminal when
using the installed loop-powered backlight op-
tion.
Refer to
for terminal positions.
•
Observe all safety regulations. Electrical wiring
should be performed in accordance with all agency
requirements and applicable national, state, and
local codes to prevent damage to the meter and
ensure personnel safety.
•
Static electricity can damage sensitive
components.
•
Observe safe handling precautions for
static-sensitive components.
•
Use proper grounding procedures/codes.
•
If the meter is installed in a high voltage
environment and a fault or installation error occurs,
high voltage may be present on any lead or
terminal.
Figure 3. Connector Board
Wiring Diagrams
Signal connections are made to a three-terminal con-
nector mounted on the rear of the display module.
The enclosure also provides one internal and one ex-
ternal earth grounding screw.
The 4-20 mA input with no backlight has a maximum
voltage drop of 1 V and is wired as shown in
The loop-powered backlight configuration requires a
total maximum voltage drop of 4 V. The backlight op-
tion is recommended for dim lighting conditions and is
enabled when wired as shown in
Figure 4. Connections without Backlight
Figure 5. Connections with Loop-Powered Backlight
