Application Note

Application Note: 101405B
Kayden Instruments

Displaying the 4-20 mA via Panel Meter on the CLASSIC 800


How to demonstrate the 4-20 mA analog output feature on the Kayden CLASSIC 800 series using a panel meter


Kayden CLASSIC 800 Series Thermal Dispersion Flow, Level, Interface & Temperature Switch & Transmitter

  • The Kayden CLASSIC supports an analog output current loop (4-20 mA). This signal is an analog representation of the thermal signal as displayed on the Thermal Signal Bar Graph on the Display Panel of the Kayden CLASSIC.
  • Please note that the 4 - 20 mA output signal corresponds to the scaled thermal signal view as determined by the range (LED - 0 and LED - 100 pointers).
  • The 4-20 mA signal may be displayed either as forward-acting (ascending 4-20 mA) or reverse-acting (descending 20-4 mA).
  • To view or adjust the 4-20 mA output current mode: (refer to the Quick Setup Guide or Product Manual)
    1. Press and release the SET button until the Fault LED is flashing & the Run Mode LED is off.
    2. The Thermal Signal Bar Graph now shows the 4-20 mA Output Mode.
      1. For forward-acting/ascending (0% = 4 mA) the 0 - 25% LEDs are illuminated.
      2. For reverse-acting/descending (100% = 4 mA) the 75 - 100% LEDs are illuminated.

Connect a Panel Meter to display the 4-20 mA analog output feature on the Kayden CLASSIC 800. (This step is required only when connecting a meter to demonstrate the 4-20 mA analog output signal. These instructions are not part of the setup for the Kayden CLASSIC 800.)

To demonstrate the 4-20 mA analog output feature of the CLASSIC 800 you will need:

  1. A Kayden CLASSIC 800 with the DC input power adapter.
  2. The Quick Setup Guide or Product Manual for the CLASSIC 800.
    (May be downloaded from
  3. A small (3-4”) length of (22 g.) insulated wire for a jumper.
  4. Any small panel meter that reads mA (250 ohm load).

Connect your panel meter as follows:

  1. Remove the Kayden CLASSIC Electronics Module from the enclosure to permit access to the wiring terminals in the base plate inside the enclosure.
  2. Connect the jumper wire between LOOP+ and +VDC.
  3. Connect the positive lead from the panel meter to LOOP-.
  4. Connect the negative lead from the panel meter to -COMMON.
  5. Re-install the Electronics Module:
    1. With the enclosure right-side-up (conduit connection facing down), tuck the excess cable behind the LEFT SIDE of the base plate starting at the top.
    2. Making sure that all wires and the cable are not covering the connectors, give the Electronics Module 1/4 turn ccw to keep the cable between the connectors.
    3. GENTLY push the CLASSIC Electronics Module into place. You should feel it click home with minimal force. If it will not seat, check the cable.

DC Input (3 or 4 Wire)
  1. 4-20 mA output is passive (opto-isolated)
  2. * 4-20 mA output current may be measured as a 1-5V voltage across a 250 Ohm resistor.
Classic 800 Display Panel
Display Panel

Display Panel Indicators:

Relay 1

On steady when Relay 1 is energized

Relay 2

On steady when Relay 2 is energized


Indicates a self-test error or fault condition

Set Point 1

On steady when viewing Set Point 1

Set Point 2

On steady when viewing Set Point 2

Run Mode

Flashing when switch is operating


Flashing when the Start-up Bypass Timer is active

Thermal Signal

Displays Thermal Signal

The Thermal Signal increases as:


The flow rate increases


The sensor is submerged


The sensor is submerged by the second liquid of greater thermal conductivity

Applicable CLASSIC 800 Models

Classic 810
Classic 810
Classic 812
Classic 812
Classic 814
Classic 814
Classic 816
Classic 816
Classic 828
Classic 828
Classic 830
Classic 830
Classic 832
Classic 832

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