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IN NEMA-4X HOUSING - MODEL 508B
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 |
