Checking analogue output voltage – Innotech Maxim User Manual
Page 50
MAXIM Installation Instructions
Page 50
© Mass Electronics Pty Ltd 2011
Edition 2.0 dated 20/11/2013
5-2.2.4 Checking Analogue Outputs
The Analogue Output wiring on MAXIM Series controllers should be checked to verify that the output
terminals are free of any external voltage, to verify continuity through the external analogue circuit,
and to verify that the resistance of the external analogue voltage is sufficient to avoid overloading the
analogue output circuit.
This procedure is applicable to controllers with dedicated Analogue Outputs, and also applicable to
those controllers equipped with Universal Outputs that have been configured to operate as Analogue
Outputs.
1. Verify that power to the MAXIM controller is turned OFF.
2. Turn the power ON for the Digital Inputs, Digital Outputs, and if applicable the Analogue Inputs.
This step is necessary to detect the presence of voltages at the analogue output terminals that
may be caused by “sneak” circuits or incorrect wiring.
3. Disconnect the active signal wire (+) from the first Analogue Output terminal.
4. Connect the red (+) lead of the DMM to the disconnected active signal wire labelled (+), and the
black (–) lead of the DMM to the Com terminal of the Analogue Output on the controller.
5. The DMM should measure 0V, as illustrated in Figure 5-4 below. Be sure to set the DMM
measurement range to measure the lowest possible voltage to ensure no voltage is present.
6. Change the DMM to measure resistance (Ω). The DMM should measure a minimum resistance
of 2,000Ω, as illustrated in Figure 5-5 on the next page. Depending on the DMM, a very high
reading in Mega Ω will indicate an open circuit condition that should be corrected.
7. Disconnect the DMM and reconnect the signal wire(+) that was disconnected in Step 3.
8. Repeat Step 3 through Step 7 for the remaining Analogue Outputs.
9. Turn the power OFF that was applied in Step 2.
V
AC
V
DC
0V
+
CHECKING ANALOGUE
OUTPUT VOLTAGE
Connected to equipment
or device
EARTH
Figure 5-4: Checking Analogue Output Voltage