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DC Input Field Configurable Limit Alarms, Single/Dual Trip

DC Input Field Configurable Limit Alarms

Item# SMLA-1

DC Input Field Configurable Limit Alarms SMLA-1 SMLA-1
  • SMLA-1 (Single Trip, DPDT, 5A) SMLA-2 (Single/Dual Trip, 2 SPDT, 5A)
  • Field Configurable Input Ranges for DC Voltage and Current
  • Exclusive “Dynamic Deadband” Prevents False Trips
  • Provides Relay Contact Closures at a Preset DC Input Level

SMLA-1 single setpoint and SMLA-2 dual setpoint limit alarms offer flexible, wide-ranging DC input capability. Voltage spans from 10 mV to 200V and current spans from 1 mA to 100 mA can be field configured. Bipolar inputs are also accepted. Both models offer configurable latching, failsafe and HI/LO operation. The SMLA-1 and SMLA-2 also include 0.25% to 50% adjustable deadbands and selectable 120/240 Vac input power.

Models SMLA-1 and SMLA-2 are equipped with a dual function diagnostic LED. The green center LED indicates line power and input signal status. Active line power is indicated by an illuminated LED. If the center LED is off, check line power and the wiring connection. If the input signal is above 100% full scale, the LED will flash at approximately 8 Hz. Below 0%, the flash rate is approximately 4 Hz.

The single setpoint SMLA-1 and the dual setpoint SMLA-2 provide the following relay outputs: SMLA-1 Single Trip (DPDT, 5A); SMLA-2 Single/Dual Trip (2 SPDT, 5A). Setpoints are top accessed multi-turn potentiometers.

The field configurable SMLA-1 and SMLA-2 limit alarm setpoints can be configured for HI, LO, latching or failsafe trip operation. Non-latching HI and LO setpoints have respective HI and LO deadbands. In a tripped condition, the setpoint is exceeded and the appropriate red LED will illuminate. The trip will reset only when the process falls below the HI deadband or rises above the LO deadband. To reset a latched setpoint the signal must be in the safe region and the line power turned off for at least 5 seconds. For proper deadband operation, a HI setpoint must always be set above a LO setpoint.

In failsafe operation, the relay is energized when the process is below the HI setpoint or above the LO setpoint (opposite for nonfailsafe). In the failsafe mode, the relays go to the tripped condition when the power fails.

The input must remain beyond the setpoint for 100 milliseconds, uninterrupted, to qualify as a valid trip condition. Likewise, the input must fall outside the deadband and remain there for 100 milliseconds to return the alarm to an untripped condition. This effectively results in a “dynamic deadband” - based on time - in addition to the normal deadband.

Voltage Input (Unipolar or Bipolar):

Range: 10 mV, 20 mV, 50 mV, 100 mV, 200 mV, 500 mV, 1V, 2V, 5V, 10V, 20V, 50V, 100V, 200V (dip-switch selectable)
Impedance: >100 kΩ
Overvoltage: 400V max
Current Input (Unipolar or Bipolar):
Range: 1 mA, 2 mA, 5 mA, 10 mA, 20 mA, 50 mA, 100 mA (dip-switch selectable)
Impedance: 20 Ω typical
Overcurrent: 200 mA max
Overvoltage: 60 Vdc
Common Mode (Input to Ground): 1000 Vdc max
LED Indications:
Input Range (Green):
>100% Input: 8 Hz flash
<0% Input: 4 Hz flash
Setpoint (Red):
Tripped: Solid red
Safe: Off
Limit Differential (Deadband):
>50 mV/5 mA: 0.25% to 50% of span
<50 mV/5 mA: 1% to 50% of span
Response Time:
Dynamic Deadband: Relay status will change when proper setpoint/process condition exists uninterrupted
for 100 msec
Normal Mode (Analog Filtering): <250 msec, (10 to 90%)
Effectivity: Setpoints are adjustable over 100% of the selected input span
Repeatability (Constant Temp):
>50 mV/5 mA: 0.1% of full scale
<50 mV/5 mA: 0.2% of full scale
Line Voltage: ±0.01%/% max
Temperature: ±0.05% of full scale/°C max
Common Mode Rejection: DC to 60 Hz: 120 dB
Isolation: 1000 Vdc between contacts, input and power
ESD Susceptibility: Meets IEC 801-2, Level 2 (4 KV)
Operating: 15 to 95 %RH @ 45°C (113°F)
Soak: 90 %RH for 24 hours @ 65°C (149°F)
Temperature Range:
Operating: 0 to 60°C (32 to 140°F)
Storage: -15 to 70°C (5 to 158°F)
Power: 120/240 Vac ± 10%, 50 to 60 Hz selectable, 2 W typical, 5 W max
Relay Contacts:
SMLA-1: DPDT (2 Form C)
SMLA-2: 1 SPDT (1 Form C) per setpoint
Current Rating (Resistive): 120 Vac: 5A; 240 Vac: 2A; 28 Vdc: 5A (external relay contact protection
is required for use with inductive loads)
Material: Silver-Cadmium Oxide
Electrical Life: 105 operations at rated load
Mechanical Life: 107 operations
Latch Reset Time: 5 seconds
SMLA-1: 209 g (0.46 lb)
SMLA-2: 282 g (0.62 lb)
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11-pin socket, DIN rail mount, for SMSC-2
0 In Stock
This item is discontinued. Please contact Technical Sales Team for assistance.
11-pin socket, surface mount
0 In Stock
This item is discontinued. Please contact Technical Sales Team for assistance.
35 mm DIN rail, 2 m (6.6') length
0 In Stock
This item is discontinued. Please contact Technical Sales Team for assistance.
Retaining spring (secures limit alarm module into DIN rail or surface mount socket)
0 In Stock
This item is discontinued. Please contact Technical Sales Team for assistance.
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