Tips & Tricks
Here you will find instructions on how to set up and operate our products, as well as troubleshooting tips.
Only 3.1 mm DIN Rail per channel
Don't I require any supply voltage?
No, the loop-powered isolator draws its auxiliary energy from the measuring circuit. The magnitude of the drop in voltage in the measuring circuit is to be found in the technical data.
What is meant by auxiliary energy?
Auxiliary energy is the energy required to operate the device. In many cases auxiliary voltage is also called supply voltage or operating voltage.
In the case of loop-powered isolators the energy required is gained from the input signal (4 - 20 mA).
What does the voltage drop at the input signify?
A loop-powered isolator, also known as a passive isolation amplifier, takes its supply from the input current. In order to take energy from the input current, the input causes a drop in voltage. The magnitude of the necessary drop in voltage is specified in the data sheet of the isolator.
What is meant by MTBF?
The MTBF, the average time until a failure occurs (MeanTime Between Failures), is a measure for the frequency with which the components fail. The greater the time, the longer is the period until a potential failure takes place.
There are two known standards for determining the MTBF value: the Siemens standard SN 29500 (2000/2004) and the military standard, MIL-217F, notice 2.
The device components used are assessed according to defined criteria for both of the standards. Depending on the mechanical structure and the load values, so-called FIT values are defined in the circuitry for each component. All the FIT values added together give the total FIT, which is then converted into hours or years and stated as the MTBF.
For example, our type DN 1012 loop-powered isolator has an MTBF of 1597.0 years according to the Siemens standard.
What is a passive isolation amplifier?
A passive isolation amplifier is an amplifier which requires no additional supply lines. These loop-powered isolators take their supply from the standard signal at the input.
Potential isolation towards the PLC
Frequently PLC inputs are not adequately potentially isolated. In this case it is feasible to install an isolation amplifier upstream from the input in order to clearly isolate the measuring signal.
Saving installation costs
Costs are saved thanks to low installation expense. Simply connect a loop-powered isolator in between in current signals which you wish to isolate. Since no extra supply is required, no additional wiring or provision of auxiliary energy is necessary.
Image of the output load at the input
The loop-powered isolator conveys the input signal to the output without converting it, i.e. 4 mA appear as 4 mA at the out put and 20 mA appear as 20 mA at the output. The situation is similar regarding the burden on the output:
If I require an 8-volt burden voltage at the output, the input will also require 8 V plus the auxiliary power from the input circuit.
Do you have further questions?
Then ask us your question by email or call our hotline at +49 30 40 998-222.