Innotech Maxim - Manual (Page 48)

MAXIM Installation Instructions
Page 48 © Mass Electronics Pty Ltd 2011 Edition 2.0 dated 20/11/2013
V AC
V
DC
0V
+ -
V AC
V DC
24V
+ -
0V
MAXIM
CONTROLLER
TERMINALS
RELAY
ON
RELAY
OFF
24V
0V
External
Relays
24V
5-2.2.3 Checking Digital Relay Outputs
The Digital Relay Outputs on MAXIM Series controllers are interfaced through relays, each with Single
Pole Single Throw (SPST) contacts.
Before checking the Digital Relay Outputs, it is important to verify that there are no short circuits
in the external wiring, which can cause the contact current to exceed the maximum rating. Excess
current through the relay contacts can result in permanent damage to the controller.
The following is the general description of the process for safely checking the Digital Relay Outputs,
with detailed steps outlined on the next page. With power applied to the digital output circuits, but
NOT to the MAXIM controller, the output circuits are checked for correct operation. Visually check to
verify that devices connected between the NO and Com terminals are OFF. If the operational status
of these devices cannot be determined by simple observation (indicator lamp ON/OFF, etc.), a DMM
can be used to measure the voltage across the particular device to determine whether or not it is
energised.
The next step is to verify that the output circuits are energised when the Digital Relay Output is
closed. For circuits using the NO contacts, a jumper wire is temporarily connected between the NO
and Com terminals and the associated device is checked to verify that it is energised.
Figure 5-3: Checking Digital Relay Output Wiring