The Smith Meter Stack Monitor is a 200A Series horizontal non-reset counter fitted with a switch-type pulse transmitter, normally mounted on a Smith PD meter. A proximity switch detects a steel target molded into the first (right-hand) counter wheel and closes once per revolution of that wheel. Its main use is on LACT units: the pulse feeds a customer-supplied timed reset, and if no pulse arrives within the set time (no flow or an accessory fault) the pump is shut down until personnel intervene. It also serves as a low-resolution pulse source for remote instruments, additive injection systems or sampler pacers. Example: on a 207A-B counter it gives one pulse per barrel.
Key specifications
Switch rating (resistive): 250 VAC, 1.5 A or 250 VDC, 0.1 A
Switch arrangement: SPDT Form C (break-before-make); duty cycle 15% of designated wheel rotation; 25 Hz max. actuation
Ambient temperature: -22 to 140 °F (-30 to 60 °C)
Running torque: 0.5 oz-in (0.4 N·cm) at 40 rpm; 1.0 oz-in (0.7 N·cm) at 200 rpm
Shock / vibration: 12 G all planes / 5 G at 30 Hz all planes
Approvals: Class I, Division 1, Groups C and D; Class I, Zone 1, Ex d IIC; UL file E79070
Wiring: 18 ga leads, 18" long (red N.C., black common, blue N.O.); 0.500-14 NPT conduit
How to read the model code
Example: SM-207A-B-1. Read the code left to right; each position selects one option:
SM (Basic unit): Stack Monitor
Counter model (Units / meter gearing): 204A-G gallons, 5:1 gallon; 207A-B barrels, 5:1 gallon; 209A-B barrels, 1:1 gallon; 214A-G gallons, 1:1 gallon; 225A-B barrels, 1:1 barrel, 1/10 bbl registration; 227A-B barrels, 1:1 barrel, 1/100 bbl registration; 224A-L litres, 1:1 dekalitre (additional counter models available)
Pulse output (Resolution): 1 = 1 pulse per revolution of the first right-hand wheel
Ordering information
Per the bulletin, please specify:
Units of registration required
Pulse resolution required
Meter gearing ratio (for example 5:1 gallon, 1:1 barrel); the bulletin's gearing table lists the volume per output-shaft revolution for each Smith meter model, C2 through M16 and the T, ST, SC, SD and SF series
Bulletin notes: one dimension is printed "0.4" (104) Dia." (0.4 in is not 104 mm; likely 4.1 in); the gearing table's footnote markers (European models only, special, available when specified) are hard to align with the rows; and SS01100 lists the stack monitor switch as Class I, Groups A, B, C and D, while SS01042 gives Groups C and D. Confirm with the factory.
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 SS01042 Rev 0.5 (2/19); 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.