SR336
Alarm Unit with RTD Input and Double Relay Outputs
SR336 is an alarm unit with programmable alarm functions designed for temperature monitoring with RTD sensors in 2-wire sensor connection in the process industry.
Two output relays with synchronous switching are available with functions such as MIN/MAX alarm in open-circuit or closed-circuit operation.
LEDs in the front indicates alarm state and correct power supply.
- Input from any RTD sensor or resistance signal in 2-wire sensor connection
- Selectable input ranges 0-300 ohm or 0- 3 000 ohm
- Two relay outputs with synchronous switching and functions
- Monostable relays for safe tripping at power failure
- SPDT relays with up to 6 A switch capacity
- The switching point and the switching hysteresis are set with potentiometers from the front
- Relay functions are set with DIP switches from the front
- Front LEDs for monitoring states and power supply monitoring
- High 4-port isolation
- Protective separation acc. to DIN EN 61140 by reinforced insulation acc. to DIN EN 61010
- 24 V DC power supply
- Mounted on a standard 35 mm DIN-rail
Technical Specification
| Input | |
| RTD sensor or resistance | Pt, Ni, Cu, KTY and further RTDs and resistance |
| Input ranges | 0 … 300 Ω / 0 … 3 kΩ (switchable) |
| Sensor connection | 2-wire sensor connection, manual compensation of line resistances required |
| Output, Relay 1 & 2 | |
| Relay contacts | Two isolated 1-pole relays (SPDT), with synchronous switching and functions |
| Contact rating | 250 VAC / 6 A, 1500 VA | 250 VDC / 0.2 A, 115 VDC / 0.3 A, 30 VDC / 6 A |
| Relay function | Monostable, Open/Closed-Circuit Operation (switch selectable) |
| Alarm function | High/Low alarm (switch selectable) |
| Adjustable alarm set-point | 0 … 110 % of input range (with 12-turn potentiometer) |
| Adjustable hysteresis | 0 to 6 % or 0 to 60 % of input range (switchable, adjustable with potentiometer) |
| Status indication | Yellow LED |
| Operation temperature | -20 °C to + 60 °C (-4 to +140 °F) |
| Galvanic isolation | |
| Input / power supply / relay outputs | Test Voltage: 4 kV AC, 50 Hz, 1 min. Working voltage: 1 kV AC/DC for OVC II, 600 V AC/DC for OVC III acc. to DIN EN 61010 |
| Relay 1 / Relay 2 | Test Voltage: 3 kV AC, 50 Hz, 1 min. | Working Voltage: 300 V AC/DC |
| Power Supply | 24 V DC, ± 15 %, approx. 0.7 W |
| Typical accuracy | Trip point: < 0.2 % full scale |
| Mounting | 35 mm DIN rail acc. to EN 60715 |