6.3.16 Input Terminal Signal Tests
The presence of signals on either the digital or analog input terminals of the adjustable frequency
drive can be verified on the adjustable frequency drive display. Digital or analog input status can
be selected or read in parameters 16-60 through 16-64.
Digital inputs
With digital inputs displayed, control terminals 18, 19, 27, 29, 32, and 33 are shown left to right,
with a 1 indicating the presence of a signal.
If the desired signal is not present in the display, the problem may be either in the external control
wiring to the adjustable frequency drive or a faulty control card. To determine the fault location,
use a voltmeter to test for voltage at the control terminals.
Verify the control voltage power supply is correct as follows.
1.
With a voltmeter measure voltage at control card terminal 12 and 13 with respect to
terminal 20. The meter should read between 21 and 27 VDC.
If the 24 V supply voltage is not present, conduct the Control Card Test (6.3.17) later in this
section.
If 24 V is present, proceed with checking the individual inputs as follows
2.
Connect the (-) negative meter lead to reference terminal 20.
3.
Connect the (+) positive meter lead to the terminals in sequence.
The presence of a signal at the desired terminal should correspond to the digital input display
readout. A reading of 24 VDC indicates the presence of a signal. A reading of 0 VDC indicates no
signal is present.
Analog inputs
The value of signals on analog input terminals 53 and 54 can also be displayed. The voltage or
current in mA, depending on the switch setting, is shown in line 2 of the display.
If the desired signal is not present in the display, the problem may be either in the external control
wiring to the adjustable frequency drive or a faulty control card. To determine the fault location,
use a voltmeter to test for a signal at the control terminals.
6 Test Procedures
High Power Service Manual for VLT
®
FC Series
Adjustable Frequency Drives
6-38
MG.90.L1.22 - VLT
®
is a registered Danfoss trademark
6
Summary of Contents for VLT HVAC FC 100
Page 219: ......