The Safety Switching Unit Behind Liquiphant FailSafe
The Nivotester FTL825 is designed to work with the Liquiphant FailSafe FTL80, FTL81 and FTL85. It forms the switching and evaluation part of the safety system rather than acting as the actual level sensor.
The connected Liquiphant detects the level condition, while the FTL825 supplies the sensor, evaluates its signal and provides the corresponding safety switching outputs.
Designed for Safety-Critical Level Applications
The FTL825 is intended for applications where point level detection is part of a functional safety system. It supports safety functions up to SIL3 in accordance with IEC 61508 and is intended for applications where redundant or diverse systems may not be practical.
This makes it particularly relevant to overfill protection and other safety-related level monitoring duties.
Permanent Self-Monitoring
The system uses a LIVE signal and permanent self-monitoring to identify faults in the connected measuring chain. This allows the switching unit to distinguish the normal measurement state from a fault condition.
An integrated locking function can also maintain the defined safety state where required by the application.
Redundant Safety Outputs
The FTL825 provides two level safety contacts based on the quiescent-current principle. These can be analyzed separately to provide a redundant output signal.
In addition, the unit provides a separate signaling contact and a fault-signaling changeover contact, allowing the safety system to distinguish level, status and fault information.
Long Proof-Test Intervals
For suitable safety applications, the specified proof-test interval can extend up to 12 years. The connected slave devices can also be tested by pressing a button, simplifying periodic proof testing where access or testing procedures are otherwise difficult.
DIN-Rail Installation
The FTL825 is designed as a top-hat rail mounting unit, making it suitable for installation inside control cabinets and centralized instrumentation panels.
Its compact switching-unit architecture keeps the safety evaluation electronics separate from the process-mounted Liquiphant sensor.
Straightforward Integration into Safety Systems
The FTL825 supports supply voltages of 85–253 VAC/DC or 20–30 VAC / 20–60 VDC, depending on the selected version.
The output arrangement provides dedicated safety, signaling and fault contacts for integration into a plant's safety or control architecture.
Key Features
- FailSafe point level switching unit
- Designed for Liquiphant FTL80, FTL81 and FTL85
- Supports functional safety up to SIL3
- Permanent self-monitoring with LIVE signal
- Proof-test interval up to 12 years
- Integrated locking / self-holding function
- Two redundant level safety contacts
- 1 signaling contact
- 1 fault-signaling changeover contact
- Two-wire connection to Liquiphant sensor
- Evaluates 4–20 mA discrete sensor signal
- Galvanically isolated signal inputs
- Top-hat rail / DIN-rail mounting
- Ambient temperature -20 to +60°C
- Supply: 85–253 VAC/DC
- Alternative supply: 20–30 VAC / 20–60 VDC
- ATEX, FM, CSA, IECEx, NEPSI and other approvals depending on configuration
- WHG overfill protection and leakage detection options
- Marine approvals available depending on configuration
Typical Applications
Overfill Protection
Used with Liquiphant FailSafe sensors as part of a safety system for detecting defined liquid level conditions and initiating a safety response.
Chemical Plants
Suitable for safety-related level switching in chemical processes where functional safety and reliable fault detection are important.
Petrochemical Processes
The SIL3 architecture makes the FTL825 suitable for safety-critical level applications in petrochemical installations.
Oil & Gas
Can be used as part of a FailSafe point level system where level detection is integrated into a plant safety function.
Storage Tanks
Suitable for safety-related high-level monitoring when paired with the appropriate Liquiphant FailSafe sensor.
Safety Instrumented Systems
Designed for applications requiring a point level safety function up to SIL3, subject to the complete safety-system architecture and configuration.
FAQ
What is the Endress+Hauser Nivotester FTL825?
The FTL825 is a FailSafe point level switching unit that evaluates signals from Liquiphant FailSafe FTL80, FTL81 and FTL85 sensors and provides safety-related switching outputs.
Is the FTL825 a level sensor?
No. The FTL825 is the evaluation and switching unit. The actual point level detection is performed by the connected Liquiphant FailSafe sensor.
Which Liquiphant sensors work with the FTL825?
The official product specification lists Liquiphant FTL80, FTL81 and FTL85 as compatible sensors.
What safety level does the FTL825 support?
The FTL825 is designed for functional safety applications up to SIL3 according to IEC 61508.
How does the FTL825 communicate with the Liquiphant?
The Liquiphant is connected to the FTL825 through a two-wire cable. The FTL825 supplies the sensor and evaluates its 4–20 mA discrete signal.
How many safety outputs does it have?
The FTL825 provides two SPST level safety contacts, which can be analyzed separately for a redundant output signal. It also provides one signaling contact and one SPDT fault contact.
What is the proof-test interval?
For suitable applications, the specified proof-test interval can be up to 12 years. Slave devices can be tested by pressing a button.
What is the ambient temperature range?
The specified ambient temperature range is -20 to +60°C.
Can the FTL825 be installed in a control cabinet?
Yes. It is designed for top-hat rail mounting, making it suitable for control cabinets and instrumentation panels.
Does the FTL825 provide overfill protection?
Yes. The FTL825 supports WHG overfill protection when used in the appropriate system configuration.
