AK10 - Multiple Parameter Display

The AK10 displays multiple parameters in most operating modes to give the technician additional information about the loop or device under test.

Source mA

When sourcing milliamps into a load, such as an I/P transducer, the AK10 will compute and display the impedance of the load.

This is particularly useful for detecting shorted turns in the coil.

2 Wire Simulate (sink mA)

When sinking mA from the loop to simulate a 2 wire transmitter, the AK10 will display the loop voltage available at the terminals.

This will detect an overloaded loop power supply. Most field devices require a minimum of 12V to operate properly. If there are additional loads in the loop, such as local loop powered indicators, the voltage at the transmitter may be ok at idle (4 ma) but may fall below the allowable limits for the transmitter at full load (20 ma).

This is an example of an overloaded loop. If you check the loop voltage at the transmitter when the process is at idle, the loop voltage looks ok.

As the process comes online and the loop current increases, the loop voltage at the transmitter will fall below allowable limits and the transmitter will probably fall outside of it's error limits. This can be a difficult problem to troubleshoot with a conventional loop calibrator.

24 Volt (power transmitter)

When sourcing 24V to power a transmitter, the AK10 will display the actual loop voltage and the loop current.

Loop Check

In loop check mode, the AK10 will measure the loop voltage at 2 load points and compute the loop parameters.

This shows a typical loop that does not have an IS barrier installed. The loop resistance is 11 ohms and the computed short circuit current would be 2.173 amps.

This shows a typical loop with an IS barrier installed. A typical IS barrier has a 300 ohm current limiting resistor. The Open Circuit Voltage (Voc) shown is the actual loop voltage measured, not the maximum voltage that the IS barrier will clamp. The loop check function can also be used on normal loops that have 1 or more loop powered indicators installed, to verify that the total loop resistance does not exceed the capabilities of the terminating device.