Levelcom 100 - Analog Output Calibration

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Analog Output Calibration

The calibration of the 4-20 mA analog output can be checked and adjusted with the following

procedure. Calibration is not a routine maintenance procedure. If you are not sure whether

to proceed with calibration please contact TMS for guidance prior to adjusting the instrument.

This procedure must be performed by a qualified technician.

Required Equipment

1. Accurate current meter for reading the current output value.

2. Wire leads to connect to the LevelCom 100 analog output connector.

Note: If the analog output is being used as a control output, be sure to secure the controlled

process before you begin because you may be disconnecting the LevelCom 100 from the

controlled process, or you may be generating meaningless control signals while performing

the calibration procedure.

Calibration Procedure

1. Connect the meter to the Analog output connector. If the LevelCom 100 is set up to

power the analog output you can connect directly to the terminals, however if the output is

set up to be externally powered you will need to connect the meter into the complete

circuit.

2. Enter the LevelCom 100 program. Access the Calibrate menu and select “AN OUT”.

Press ENTER. “ZERO” will be displayed. Press ENTER. The meter should read 4 mA.

If it doesn’t, adjust the ZERO potentiometer on the analog output board until the meter

reads 4 mA. (Refer to Figure 24 for the location of the ZERO potentiometer)

3. Press the UP or DOWN keys to scroll to “SPAN” and press ENTER. The meter should

read 20mA. If it doesn’t, adjust the SPAN potentiometer until the meter reads 20 mA.

(Refer to Figure 24 for the location of the SPAN potentiometer)

4. Press the UP or DOWN keys to scroll to “ZERO” and press ENTER.

5. The meter should read 4 mA. If it does the calibration is complete, if not repeat steps 2 –

4 until the meter reads 4 mA when you enter ZERO, and 20 mA when you enter SPAN.

6. Now you can check the linearity of the output with the other items in this menu. When the

span and zero calibration is done entering the following menu items should give the

following meter readings:

25% - 8 mA

50% - 12 mA

75% - 16 mA