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TF101ZG2
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Extending the sensor line: which cable?
Sensor lines can be extended with a screened cable, e.g. LIYCY 3*0.34mm²
Calibration of scale
For 3-phase voltage relays without neutral connection, the voltage is evaluated to an artificial neutral point. The scale is calibrated for single-phase voltage change. With single-phase voltage change, the neutral point shifts in the direction of the phases with the higher voltage. Symmetrical voltage change results in larger voltage changes compared to the (unchanged) neutral point. As a result, the device switches earlier.
Suction does not switch on although machine is running
Suction does not switch on although machine is running for at least one minute. The current consumption of the machine is too low or the response threshold is too high. Reduce response threshold by potentiometer or via parameter (STW with display). For STW devices without setting option, loop cables several times through the STWA1(H) current transformer.
Regarding cable length, what is the maximum length of the connection cable?
Since PTC thermistors already have a very high resistance and the resistance changes from <250 Ω to over 4 kΩ in the range of the nominal response temperature, the ohmic resistance plays a very minor role, so that lengths of 500 m or longer are generally not critical. The measuring circuit wires are to be laid as separate control wires. The use of cores from the motor supply line or other main power lines is not permitted. If strong inductive or capacitive interference is to be expected from parallel power lines, shielded control lines must be.
Test PTC thermistors: How can I test PTC thermistors to see if they are working correctly?
This is usually not possible in the installed state. The cold resistance of a 3 PTC thermistor chain is approx. 60 to max. 750 ohms (typically 150-300 ohms): This means that, at best, PTC thermistors from a production batch can be used to draw a conclusion about short-circuiting of a sensor in the chain. Up to 20 K before reaching the nominal response temperature, the resistance can even drop as the temperature rises. The trigger point at overtemperature can only be determined by practical tests (heating in an oil bath). The nominal response temperature can be recognized by the colors of the connecting wires (see ZIEHL catalog). ATTENTION: Measuring voltage max. 2.5 V.
What is the service life of PTC thermistors? (Technical reliability/MTBF
We do not have any numerical values for the failure rate from the manufacturer of the PTC thermistor pills. As an empirical value from the ZIEHL company, a failure rate of ≤ 10 fit can be assumed. This corresponds to comparable values for components made of ceramic material (e.g. ceramic capacitors). From this, an MTBF of ≥ 100 years can be calculated. These figures depend on the failure criteria, the stress and the operating time. A supplementary specification for estimating the service life for PTC thermistors of type MINIKA® under operating conditions can be made for PTC thermistors of similar design (e.g. for level monitoring). Here, the manufacturer has provided information on > 5000 switching cycles.
Can PTC thermistors be connected to inputs for Pt 100?
For temperature relays for Pt 100 with adjustable hysteresis, e.g. ZIEHL -temperature relay type TR, PTC thermistors can also be connected to the sensor inputs. For this purpose, the input is programmed for the connection of a 2-wire sensor and a resistor 150 Ohm is connected in parallel to the PTC thermistor circuit. When the switching point is set to 115 °C and hysteresis 20 °C, the device switches like a PTC-resistor relay. Temperature displays and analog outputs are unusable. We recommend the use of PTC thermistor relays type MS ... .
Set triggering temperature
How can I set at which temperature the relay switches off? PTC relays have a fixed response point at approx. 3 to 4 kΩ. The actual switching point depends on the PTC sensor, which becomes highly resistive at a certain nominal response temperature (NAT). As a rule, up to 6 PTC thermistors can be connected in series. PTC thermistors with different NATs may even be connected in series (e.g. for monitoring winding and core, or bearing temperatures to different values.
Measuring voltage at sensor input too high?
PTC thermistor sensors are often provided with notes that the measuring voltage must not exceed 2.5 V. Measuring inputs of PTC thermistor tripping devices, however, usually have significantly higher voltages in no-load operation (up to 20 V). This is not critical, since the voltage collapses immediately when a sensor is loaded. With cold (low-impedance) sensors, the measuring voltage must not exceed 2.5 V. For hot (high-impedance) sensors, it must not exceed 7.5 V.
Create MAC filter for ZIEHL IP devices when using DHCP?
The use of MAC-based filtering on the DHCP server can be useful for security reasons. ZIEHL IP devices can be enabled by the following entry in the MAC list: 00-12-E4-* This is an entry with the ZIEHL manufacturer ID and a WildCard.
Connection of measuring transducers
Please see the connecting diagram in the operating manual on the individual product page of the measuring transducers.
Difference between closed current and working current
Closed Current= Okay-state blocked (wire break leads to tripping) Working Current= Okay-state dropped (wire break remains undetected)
Connecting sensors in hazardous areas to TR devices
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