STANDARD FEATURES
FM, CSA, BASEEFA Intrinsic Safety
Certification
Powered by 1-5, 4-20 or 10-50 mA Signal
2.5 V Max Voltage Drop
0.35 in (8.9 mm) Liquid Crystal Display
2,000-Count Zero Suppression or Elevation
100 to 2,000 Count Span Adjust
Selectable Dummy Right-Hand Zero
û40░C to +85░C Operation
Compact, 2.9 in Diameter Die-Cast Housing
Waterproof to 35 kPa (5 psi)
Shock Resistant to 55 g |
![Model 508B](/file/20394/OMEGA and Dilbert Too!.iso/Omega/Databook/images/a13p1.GIF) ![Mechanical Reference](/file/20394/OMEGA and Dilbert Too!.iso/Omega/Databook/images/MACHREF.gif)
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OPTIONS
CENELEC Intrinsic Safety Certification,
FM, CSA
1/2 EMT Conduit Fitting
1/2 NPT Pipe Fitting
Relay-Track Mounting Adapters
External Explosion-Proof Housing
Companion Current Transmitters
DESCRIPTION
Model 508B is a two-wire current-loop indicator that is powered directly
by a 1-5 mA, 4-20 mA or 10-50 mA process loop signal, with a maximum voltage
drop of 2.5 V. No separate power supply connections are required. This
reduces overall hardware and field wiring costs and provides immunity
from most electrical noise encountered in process control environments.
The electronics are isolated from the case.
READOUT OF PROCESS VARIABLES
The 508B provides extensive zero and span adjustment capability, so that
it can read out directly in percent or in engineering units for process
variables such as pressure, flow, temperature, or level. Its liquid crystal
display provides 3 1/2 active digits, a selectable dummy right-hand zero,
and four programmable decimal points. By changing two internal jumpers,
the normal positive slope response of the 508B can be reversed, so that
increasing the input decreases the reading.
EASY TO CONFIGURE AND CALIBRATE
Both span and zero are fine-tuned with precision multiturn potentiometers.
These are accessible through holes in the die-cast cover, which are normally
sealed with fluorosilicone plugs. Coarse zero and span steps are selected
by removing the cover with attached electronics and changing plug-in jumpers.
DESIGNED FOR HARSH ENVIRONMENTS
All versions of the 508B are rated for operation from û40 to +85░C (û40
to +185░F) with specified accuracy. The case is made of die-cast metal
and is waterproof to 35 kPa (5 psi). The electronics are firmly connected
to the case top, so that the meter can withstand high vibration and shock.
Mounting options include a male 1/2 EMT conduit fitting and a male 1/2
NPT pipe fitting in lieu of the normal rail or surface mount. These fittings
eliminate the external screw terminals and provide a NEMA-4X rating.
INTRINSIC SAFETY CERTIFICATION
FM and CSA intrinsic safety certification is standard. Additional CENELEC
intrinsic safety certification is optional. Intrinsic safety certification
allows the 508B to be used in worst-case hazardous environments with no
need for an explosion-proof housing, provided that an intrinsic safety
barrier is used to limit the voltage and current that may be introduced
in the hazardous environment. FM certification (USA) is for Class I, II,
III, Division 1, Groups A, B, C, D, E, F, G. The FM certification number
is 2P1A7.AX (3610). CENELEC certification (Europe) is to level EEx ia
IIC T4 in accordance with CENELEC standards EN 50 014 (1977) + A1 to 4
and EN 50 020 (1977) for use in Zone 0 (worst case) hazardous environments.
The BASEEFA certification number is Ex 85B2167.
EXPLOSION-PROOF HOUSING OPTIONS
Three external NEMA-7 explosion-proof and NEMA-4 waterproof enclosures
are available as options for use in hazardous locations in Class I, Groups
B, C, D; and Class II, Groups E, F, G. All offer a glass viewing window,
two female 1/2 NPT pipe fittings, all required internal mounting hardware,
and mounting flanges for a wall or bulkhead. Option EPW3 is a single-height
enclosure for one 508B loop-powered indicator. FM and CENELEC EEx d II
C certification is standard. Option EPW2 is a double-height enclosure
for a 508B loop-powered indicator on top and a 500 Series isolated two-wire
4-20 mA transmitter on the bottom for indicating transmitter applications.
FM and CENELEC EEx d II C certification.
SPECIFICATIONS
SIGNAL INPUT
Signal: 1-5 mA, 4-20 mA or 10-50 mA (jumper-selectable)
Linear Range: 0.3 to 50 mA
Protection: Up to 200 mA forward, 1000 mA reverse
Forward voltage drop, max: 2.5 V up to 50 mA
Input Resistance: 50 ohm at 1-5 mA, 12.5 ohm at 4-20 mA, 5 ohm
at 10-50 mA
Zero Adjust: û2,000 to +2,000 counts (4 jumper- selectable ranges
plus fine adjustment)
Span Adjust: 0 to 2,000 counts with fine adjustment
NMR: 46 dB, 50/60 Hz
CMR: (meter to case) 120 dB, DC to 60 Hz
CMV: (meter to case) 700 Vp
RFI Susceptibility: Less than ▒0.5% of span with conduit fitting
or external explosion-proof housing in 10V/m field strength at 27 or 440
MHz
ACCURACY AT 25░C
Maximum Error: 0.1% of span ▒1 count 00 Zero tempco ▒0.1 count/░C
typical, ▒0.2 count/░C max
Span Tempco: ▒0.005% of span/░C typical, ▒0.015% of span/░C max
ANALOG-TO-DIGITAL CONVERSION
Technique: Dual-slope, average-value
Polarity: Automatic
Integration Period: 100 msec
Read Rate: 2.5/sec
DISPLAY
Type: 7-segment, LED
Height: 0.35" (8.9 mm)
Symbols: û1.8.8.8.0.0 (3 1/2 active digits plus two jumper-selectable
dummy right-hand zeros)
Decimal Points: Four positions, jumper-selectable
Overrange Indication: Three least-significant active digits blank
ENVIRONMENTAL
Operating Temperature: û40 to +85░C (û40 to +185░F)
Vibration: 0.06" (1.52 mm) double-amplitude cycled at 10-80 Hz
Shock: 55 g half-sine, 9-13 ms duration
Waterproof Pressure: 35 kPa max (5 psi)
MECHANICAL
Diameter: 2.9" (74 mm)
Height, Including Barrier: 1.9" (48 mm)
Weight: 14oz (400 g)
ELECTRICAL CONNECTIONS
508B-1: 3-terminal barrier strip with #6 screws
508B-2: 1/2" EMT male conduit fitting with two 0.3 meter #18 stranded
wires
508B-3: 1/2"
NPT male pipe fitting
with two 0.3 meter
#18 stranded wires
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