Rockwell Automation 61C350 2-In/2-Out 0-10 Volt Analog Rail Module - Manual (Page 38)

5Ć4
Step 3. Try to clear the condition by disconnecting and then
reĆconnecting the I/O Rail cable. Make certain the
connections are tight. If applicable, check the
connections between the host and the Local I/O Head,
the AutoMate Remote I/O Head, or the DCS
5000/AutoMax Remote I/O Head. Check that the input
connector pins are not bent.
Step 4. Turn off power to the external hardware. Verify that the
wiring to the external hardware is tight and functioning
correctly.
Step 5. Turn on power to the external hardware. Before testing,
make certain that the external hardware cannot respond
to output signals from the Analog Rail module.
For input channels, use the Executive software to read
the value on the input channels. Use a voltmeter to read
the input signal and compare the two. If the signal is
being converted correctly, there is a problem with the
external hardware or wiring.
For output channels, use the Executive software to write a
value between 0 and 4095 to the channels. Use a
voltmeter to verify that the signal on the terminal points is
proportional to the value. If the signal is being converted
correctly, there is a problem with the external hardware or
wiring.
Step 6. Troubleshoot the external hardware, the wiring, and the
host.
5.4 Constant UnderĆRange
Problem: the underĆrange bit (12 decimal) on an input channel
register is constantly set to 1. Assuming that the power supply for
the external hardware connected to the input channels is providing
an input signal within the specified limits (0Ć10V), the possible
causes of this problem are incorrect (reversed) input signal wiring
on the module faceplate, a loose connector on the analog I/O
section of the faceplate, or loose or malfunctioning wiring. Follow
the steps below to isolate the problem.
Step 1.
Stop any application tasks that are running. Turn off
power to the external hardware connected to the module.
Turn off input power (120 VAC or 24 VDC) to the module.
Step 2. Verify that the 12Ćpoint connector on the analog I/O
section of the module faceplate is securely attached to its
mating half.
Step 3. Verify that the signal wiring on the module faceplate is
correct. See step 9 in section 3.2 for more information.
Verify that the wiring is tight and functioning properly.