` SR335 Alarm Unit - Alpha Controls & Instrumentation Inc.


SR335 Alarm Unit

Pt100 input and double relay outputs

$536.00 CAD
Normally ships in 1-2 Weeks

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SR335 is designed for industrial temperature monitoring with Pt100 sensors in 2- or 3-wire connection. Two output relays with individually adjustable trip functions are available. LED’s in the front indicate alarm state and correct power supply.



• Input from Pt100 sensors in 2- or 3-wire connection
• Selectable, pre-calibrated temperature ranges
• Two relay outputs with independent switch functions
• Monostable relays for safe tripping at power failure
• SPDT relays with 6 A switch capacity
• High configuration flexibility with DIP switches
• Trip levels and hysteresis adjustable from the front
• Three front LED’s for trip indication and power supply monitoring
• 4 kV isolation between input, output and power supply
• Protective Separation acc. to EN 50178
• Universal 24 V AC and DC power supply
• DIN-rail mounting

Sensor Pt100, Pt200, Pt500 and Pt1000 (switch selectable)
Measuring Range Zero: -100C / -50C / 0C / 50 C (switch selectable)
Span: 100C / 200C / 300C / 400C (switch selectable)
Sensor Connection 2-wire and 3-wire (switch selectable)
Output, Relay 1 & 2
Relay Contacts 1-pole switch over contact (SPDT)
Contact Rating Pt100, Pt200, Pt500 and Pt1000 (switch selectable)
Relay Function Monostable, Normally active or passive (switch selectable)
Alarm Functions, Relay 1 High/Low alarm (switch selectable)
Alarm Functions, Relay 2 High/Low alarm or Power Failure alarm (switch selectable)
Alarm Indication Alarm state indicated by yellow LED
Response Time Ca. 20 ms (fixed)
Operation Temperature -20C - 60C (-4F - 140F)
Galvanic Isolation
Input / Power Supply / Relay Outputs 4 kV AC, 1 min
Relay 1 / Relay 2 2.5 kV AC, 1 min
Power Supply
Voltage 24 V AC/DC +/- 15%, 48 Hz - 62 Hz (AC supply)
Power Consumption AC: ca. 2 VA
DC: ca. 1 W
Typical Accuracy Trip point: +/- 0.2% of span
Mounting Rail acc. to DIN EN 50022, 35 mm