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8 Troubleshooting
8.1 PLC Version Number Check
FX
3G
/FX
3U
/FX
3UC
PLC User's Manual - Analog Control Edition
FX3U-4AD/FX3UC-4AD (4-channel Analog Input)
8. Troubleshooting
This chapter describes troubleshooting methods and error codes.
If the A/D conversion data is not input, or if the proper digital value is not input, check the following items:
• PLC version number
• Wiring
• Program
• Error status
8.1 PLC Version Number Check
Verify that the PLC being used is of the following version or later.
FX
3U-4AD
FX
3UC-4AD
→ For a detailed description of version number check method, refer to Section 1.3.
8.2 Wiring Check
Check the wiring as follows:
1. Power
The 4AD needs driving power. Verify that the power supply line is properly connected. Also check that the 24
V indicator lamp of the 4AD is on.
2. Analog input line
Use the 2-core twisted shielded cable for the analog input line. In addition, be sure to separate the analog
input line from any other power lines or inductive lines.
3. Use of current input mode
To use the current input mode for a channel, be sure to short-circuit the line between the V+ terminal and the
I+ terminal of the channel.
Without short circuiting the terminals, it is impossible to obtain the correctly converted digital values.
→ For a detailed description of wiring, refer to Chapter 4.
8.3 Program Check
Check the program as follows:
1. Storage devices
Check whether the device holding digital values contains any values written by other programs.
2. Setting of averaging time and digital filter function
Check if the averaging time or the digital filter function is set for the same channel. It is not possible to set both
functions for the same channel.
Compatible PLC Version number
FX
3U Series PLC Ver. 2.20 or later
FX
3UC Series PLC Ver. 1.30 or later
FX
3G Series PLC Ver. 1.00 or later
Compatible PLC Version number
FX
3UC Series PLC Ver. 1.30 or later