The Smith Meter Model LNC (Large Numeral Counter) Transmitter mounts on a 600 Series LNC on a Smith PD meter and provides a contact closure for signaling remote instrumentation. It chops a fixed-level input voltage into a square-wave pulse with minimum contact bounce, for transistorized circuits such as an electronic drive control. A dry reed switch, magnet and gear train in a die-cast explosion-proof housing (screw-type cover) give 1 or 10 contact closures per revolution of the LNC right-hand wheel. It can be factory-mounted or field-mounted.
Key specifications
Models: LNC-1 = 1 contact closure per revolution of the LNC right-hand wheel; LNC-10 = 10 closures per revolution
Switch: Dry reed switch, SPST; contact resistance 500 milliohms
Contact rating: 50 VA resistive max.; 250 V (AC or DC) max.; 3 A continuous max.
Actuating time / contact bounce: 0.001 second average each
Speed: 0 to 2,500 contact closures per minute; contact timing 40-50% on
Operating temperature: Compensated for -40 to 160 °F (-40 to 71 °C)
Torque: 3.0 oz-in (4 N·cm) max.
Life expectancy: 20 million closures at rated load or 2 million input-shaft revolutions; up to 100 million at half rating with 10:1 ratio, up to 200 million at reduced load
Contact protection: Arc suppression required on AC circuits
Housing / approvals: UL-listed, CSA-certified explosion-proof, Class I, Groups C and D; 1/2"-14 NPT conduit entry, #18 AWG leads 16" long
How to specify / order
The bulletin has no position-by-position model code; order by model number:
Specify LNC-1 (1 pulse per revolution) or LNC-10 (10 pulses per revolution)
State whether the transmitter is to be factory-mounted on the meter or supplied for field mounting
Give the meter model and serial number and the LNC units of registration so the pulse value per unit volume can be confirmed
Flexible conduit is recommended to relieve stress on the transmitter/housing interface
Bulletin notes: the revision block says the modeling code was updated, but the bulletin only lists the two model numbers; SS01100 adds a CENELEC EExd IIA T6 approval for this transmitter that SS01045 does not mention. For high-resolution pulses see the HR-LNC transmitter (SS01046).
Pricing and lead time are quoted per configuration. Send the model number (or the details above) with your meter model and serial number to Flow Measurement Services for a quote. Specifications summarized from Smith Meter bulletin SS01045 Rev 0.1 (1/93); confirm current data with the factory before ordering.
Smith Meter (formerly FMC Technologies / TechnipFMC Measurement Solutions), now manufactured by Guidant. Flow Measurement Services supplies and services Smith Meter equipment.