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
Compact, 2.9
in Diameter Die-Cast
Housing
100 to 2,000
Count Span Adjust
û40░C to +85░C
Operation
Waterproof to
35 kPa (5 psi)
Shock Resistant
to 55 g
Selectable Dummy
Right-Hand Zero
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
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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