Innotech Maxim - Manual (Page 46)

MAXIM Installation Instructions
Page 46 © Mass Electronics Pty Ltd 2011 Edition 2.0 dated 20/11/2013
1 2
24V
DIGITAL CONTROLLER
24V
TRANSFORMER
EARTH
Circuit Breaker
OFF
DMM
From 240V
suply
24V
0V
5-2.2.1 Checking Power Inputs
The power inputs must be inspected to ensure that the supplied voltage is within the specifications
of the particular controller, as illustrated in Figure 5-1 below. In cases where a DC power source is
utilised, correct polarity must be verified, and the 0V terminal must be connected to ground. When
an AC power source is utilised you must verify that the AC Neutral wire is properly earthed and
connected to the 0V terminal on the particular controller.
You can check and verify correct operation of the 24VAC and 24V DC power supply inputs by
following the steps below:
1. Verify that the main power and the circuit breaker are both OFF.
2. Verify that the resistance between the main earth link of the enclosure and Terminal 2 of the
controller measures 3Ω or less.
3. Connect the red (+) test lead of your Digital Multi Meter (DMM) to the line voltage side (24V from
the transformer) of the circuit breaker, and the black (–) lead of the DMM to the 0V terminal of
the transformer.
4. Verify that the DMM is set to the proper range to measure 24V. In most cases the AUTO setting
will suit most measurements.
5. Ensuring that the circuit breaker remains OFF, now only turn the 240V supply power ON and
observe the reading on the DMM. The measured voltage should be 24V within ±10%. Please
note that the DMM must be set correctly to measure either AC or DC voltage depending on the
type of power source connected to the controller.
6. You can now turn the 240V supply power OFF and disconnect the DMM.
7. The above steps can be repeated to check the power inputs on other controllers.
Figure 5-1: Checking Power Input Voltage