The PD685 is an ATEX and IECEx intrinsically safe, NEMA 4, IP67 loop-powered indicator that is easy to install and program. It can be seen from considerable distance in bright sunlight or dimly lit areas when the standard backlight feature is activated. The fact that this meter is loop-powered means that there is no need to run additional, costly power lines into a hazardous area. The meter gets all of the power it needs from the 4-20 mA loop and its 1 V (4 V with backlight) drop results in a minimal burden on the loop. The meter features a wide -40 to +75°C operating temperature range and is available with a ½" conduit hole in a location of your choice for easy installation. Calibration is a quick two-step process involving the adjustment of only two sets of coarse and fine, non-interacting potentiometers.
- NEMA 4, IP67 Loop-Powered Field-Mount Process Meter
- 4-20 mA Input
- 1.1" (28 mm) 3½ Digits LCD Display; -1999 to 1999
- 1 V Drop (4 V Drop with Backlight)
- HART® Protocol Transparent
- Loop-Powered Backlight Standard
- Operates from -40 to 75°C (-40 to 167°F)
- Coarse and Fine Zero & Span Potentiometer Adjustments for Easy Field Scaling
- Plastic NEMA 4, IP67 Enclosure
- ATEX and IECEx Certified as Intrinsically Safe
- CE Marked
- Conformal Coated PCBs for Dust and Humidity Protection
- One ½" Conduit Hole (Rear, Top, Bottom or None)
- Pipe & Panel Mounting Kits
- Stainless Steel Tag Available
Conduit Installation Instructions
- Remove the printed circuit board from the enclosure.
- Connect appropriate size conduit fittings to the hole provided. For enclosures without a pre-drilled hole, the installer must make a hole in accordance with the instructions for the particular conduit fitting being installed.
- Connect conduit (with attached hubs) to the enclosure. Conduit hubs must be connected to the conduit prior to being connected to the enclosure. Use only conduit hubs that are designed to maintain NEMA 4 or IP67 ratings.
- Remove the enclosure cover from the base.
- Insert mounting hardware into mounting holes in enclosure base.
- Secure the enclosure base to the mounting surface using the inserted hardware.
- Re-attach the enclosure cover to the base.
The only tools needed for calibration are a calibrated current source and a small slotted/flathead screwdriver.
To access the input terminals it is necessary to remove the enclosure cover and the printed circuit board. This is done by loosening the four screws on the enclosure cover and removing the cover. Completely loosen both thumb screws that hold the printed circuit board to the enclosure. Turn it over to gain access to the reverse side. Then, proceed to connect a calibrated current source.
Decimal Point Selection
The decimal point jumper array J2 is located in the lower right corner of the printed circuit board next to the display. It is labeled DDD.D, DD.DD, and D.DDD. Place a jumper over both pins of DDD.D for a display of 199.9, DD.DD for 19.99, or D.DDD for 1.999.
LO and HI coarse and fine calibration controls are located below the display. The meter is factory calibrated to display -500 at 4 mA and 1500 at 20 mA. Use the HI and LO COARSE controls for large range changes during calibration and the HI and LO FINE controls for precision changes. Apply a 4 mA signal and adjust the LO controls to display the desired reading. Apply a signal between 16 and 20 mA and adjust the HI controls to display the desired reading. Complete the calibration procedure by making minor adjustments to the LO and HI controls as necessary.
Installation of the meter involves removing the printed circuit board from its enclosure and connecting a ½" conduit fitting to the hole provided. Refer to PD685 ATEX and IECEx Certified Loop-Powered Meter Intrinsic Safety Control Drawing diagrams (LIM685-2) for further details. Wall mounting holes are located in each corner of the enclosure.
Disconnect power to the loop and wire the meter as illustrated in Figures 3 & 4 for 2-wire transmitter configuration, Figures 5 & 6 for 4-wire transmitter configurations, and the PD685 ATEX and IECEx Certified Loop-Powered Meter Intrinsic Safety Control Drawing diagrams (LIM685-2) supplied with the instrument. Connect the loop return wire to S- to disable the backlight feature or connect it to B- to enable the backlight feature.