Diamond-SIS® is a cost-effective, stand-alone, non-programmable electronic (non-PE) logic solver designed specifically for process industry applications. Also commonly described as a single-loop logic solver, safety trip amplifier, or analog safety relay, Diamond-SIS® provides a simple, highly reliable solution for low-integrity protection layers and safety instrumented systems (SIS).
- Safety Certified: Diamond-SIS® is SIL 3 compliant to IEC 61508. With an operating range of -30°C to +75°C, it can be installed close to the equipment being protected, even in demanding process environments. Local installation can reduce wiring, infrastructure, and overall implementation costs.
- Flexible Inputs and Trip Settings: Diamond-SIS® accepts analog or digital process signals. Two field-adjustable set points allow protective action for both high and low process conditions, providing considerable flexibility from a single device.
- Powerful Outputs: With a 5-amp output rating, Diamond-SIS® can de-energize multiple final elements, including motor control circuits and solenoid-operated valves. This allows a single protective function to initiate the actions necessary to bring the process to a safe state.
- Flexible Power Options: Diamond-SIS® systems can be supplied for 24 VDC, 110 VAC, or 240 VAC power and configured with redundant power supplies and/or an uninterruptible power supply (UPS) to support application availability requirements.
- Easy Integration: Process variables and system alarms can be communicated using serial or hardwired connections. Diamond-SIS® can also repeat the process signal to another control system for operator display, alarms, trending, or other monitoring.
KEY FEATURES
- IEC 61508 SIL 3 Compliant
- High reliability
- Proven technology
- Rugged design
- Field mountable
- On-line testable & repairable
- Remote process variable & system status monitoring
- Signal communication to control systems
- No programming
- Class 1, Div 2
- A Simpler, Lower-Cost Alternative to a Safety PLC
Diamond-SIS® delivers the protection you need without the programming, cybersecurity exposure, and complexity of a PLC-based safety system. It is a practical choice when the application calls for independent, highly reliable protection without unnecessary complexity.
Each Diamond SIS® consists of the following elements:
- Power Supply
- Input Amplifier (I/U converter, differential or single ended input)
- Turn-on delay timer
- DC to DC Isolator
- Isolated Output amplifier
- Comparator High/Low
- Trip delay timer
- Output – Dry Relay Contacts
POWER SUPPLY
The power supply receives an external +24Vdc to generate the internal Vcc voltages incorporated by the Diamond-SIS. Polarization and over-current protection circuits keep the Diamond-SIS fault free.
INPUT AMPLIFIER
The high precision, low compliance voltage current loop receiver converts a differential or single ended sensor current input (4-20 mA) into an equivalent voltage level. It also provides an external voltage reference for the comparators so that any shift in reference voltage will be ratiometric and will not influence the trip thresholds.
TURN ON DELAY TIMER
The turn on delay timer prevents relay flutter when the supply voltage to the channel electronic is applied. It holds the input in the “OFF” state until the internal Vcc supplies have stabilized and the Diamond-SIS has detected the process condition. The turn on delay timer does not influence the trip delay time.
DC TO DC ISOLATOR
The analog input, analog output, alarm contact outputs and the 24Vdc power are mutually isolated. This accomplished by first converting the analog input into a digital signal. The digital signal is then optically isolated twice. Isolated power for the analog input and output circuitry and their associated loop supplies are handled by a single push-pull chopper, driving four transformers.
ISOLATED OUTPUT
The digitized analog signal is converted back to a 4-20mA signal precisely repeating the process input.
LO COMPARATOR
The low comparator compares the I/U converted sensor signal with a preset trip threshold. The threshold voltage is adjusted via a high precision 10-turn potentiometer. If the sensor signal falls under the threshold, the comparator changes output and the trip delay circuit is triggered. The low comparator output will also trigger and hold on a detected open loop.
HI COMPARATOR
The high comparator compares the I/U converted sensor signal with a preset trip threshold. The threshold voltage is adjusted via a high precision 10-turn potentiometer. If the sensor signal raises above the threshold, the comparator changes output and the trip delay circuit is triggered. The high comparator output will also trigger and hold on a detected shorted loop.
TRIP DELAY TIMER
The trip delay timer circuit delays the actuation of the output relay by an adjustable time. (.2 – 20 seconds). The trip delay timer is not asserted when the process returns between the high and low threshold of the comparator. The delay time is adjusted via a high precision 19-turn potentiometer.
OUTPUT RELAY
If the sensor signal exceeds the low or high threshold longer than the trip delay time, the output relay is activated. If the sensor signal returns into the normal range before the delay time has expired, the outputs are not activated.
SPECIFICATIONS
Supply Power: User specified, 24VDC/110VAC/240VAC
Input: 4-20 mA DC or discreet (dry contact)
Output: 5 Amp resistive dry contact
Accuracy: 1% of span
Temperature: -40 to +80oC Storage / -30 to +75oC Operating
Environment: All internal components rated Class I Div II Groups A/B/C/D
Enclosure: NEMA 4X – choice of materials