IDEC MicroSmart FC6A Replacement Guide

Typical application: Connect diesel engine ECU to read speed, water temperature, oil pressure, fault codes, etc., or control engine start stop and throttle.

The complete process of replacing the discontinued PLC

8.1 Identify key parameters of the original PLC

Before replacing discontinued PLCs (such as IDEC FC5A/FC4A, Mitsubishi FX series, Omron CP1 series, etc.), it is necessary to record:

I/O points and types: digital input/output points, analog input/output points.

Input voltage: AC 110V, 24V DC, 12V DC or other.

Output types: relay, transistor (NPN/PNP), bidirectional thyristor.

Power supply voltage: AC 220V, 24V DC, 12V DC.

Communication requirements: Do you need to communicate with touch screens, frequency converters, and upper computers (Modbus RTU/TCP, CAN, etc.).

Special functions: high-speed counter, pulse output, shaft control.

8.2 Select the closest model based on the FC6A selection table

Example:

Reasons for recommending FC6A model based on original PLC specifications

24V DC power supply, 8-in/6-out relay FC6A-C16R1CE 16 point body, relay output

24V DC power supply, 14 input/10 output transistor source type FC6A-C24P1CE point and output type matching

220V AC power supply, 24 in/16 out relay FC6A-C40R1AE 40 point body built-in 24 in/16 out

Engineering vehicles require reading engine CAN data FC6A-C40R1CEJ with J1939 interface

Mobile devices powered by 12V batteries FC6A-C40P1DE or K1DE 12V transistor versions

If the number of I/O points of the original PLC exceeds the maximum number of points (40 points) of the FC6A body, an expansion module is required. FC6A supports local expansion of FC6A series (digital/analog/temperature, etc.), with a maximum total of 520 digital+126 analog points.

8.3 Hardware Installation and Wiring

Physical installation: FC6A is installed using standard 35mm DIN rails, with widths depending on the number of points: 16 point and 24 point units are approximately 87mm wide, and 40 point units are approximately 155mm wide. If the original PLC installation holes are different, it is necessary to replace the guide rail or process the base plate.

Power wiring: AC models are directly connected to 100-240V; DC models are connected to the corresponding DC voltage (pay attention to positive and negative polarity). The 12V model cannot be connected to 24V.

Input wiring: The input of FC6A is sink source compatible, which can be wired as NPN (common positive) or PNP (common negative) without changing the sensor type. It is recommended to use shielded cables with a length not exceeding 3 meters (to meet electromagnetic immunity).

Output wiring: Relay output can directly replace the original relay output; The transistor output needs to confirm that the load voltage is consistent with the original system (24V or 12V). If the original output is AC 110/220V, the relay output model must be used.

Communication wiring: Ethernet uses CAT. 5e and above Ethernet cables; Use dedicated programming cables or self-made RJ45 to DB9 cables for serial ports (see manual for pin definitions); CAN (J1939) uses shielded twisted pair cables with a terminal resistance of 120 Ω.

8.4 Program Conversion

Use IDEC's WindLDR programming software (supporting FC6A) or Automation Organizer. If the original program is FC5A/FC4A PRJ files can usually be directly imported and CPU model settings can be changed, but it is necessary to check:

I/O address mapping: The input and output addresses of FC6A range from I0~I27 (24 point model) or I0~I39 (40 point model), which may be different from the old model. Batch reallocation is required.

Special registers: Some system flag bits (such as normally ON, normally OFF, scan pulses) may have address changes.

High speed counter configuration: The high-speed counter parameters of FC6A are set through software, which is different from the hardware mode switch of the old model.

Communication instructions: The syntax of Modbus instructions (such as MODR, MODW) may be compatible, but testing is recommended.

If the original PLC is from another brand (Siemens, Mitsubishi, etc.), the ladder diagram needs to be rewritten according to the logic of the new program. The rich instruction set of FC6A (arithmetic, comparison, shift, PID, floating-point, etc.) can be utilized to achieve the same functionality.

8.5 Testing and Verification

Before powering on: Use a multimeter to confirm that the power supply voltage is correct and that there is no short circuit at the output terminal.

Download the program: Connect the PC via USB or Ethernet and download the rear CPU for RUN.

Mandatory testing: Use software to force the output point ON/OFF and check the action of the on-site actuator.

Input check: manually trigger on-site sensors, observe input indicator lights or software monitoring.

Communication testing: Verify data exchange with touch screen, frequency converter, and SCADA one by one.

Run with load: Run continuously for at least 8 hours, check CPU temperature, power stability, and functional integrity.

Common troubleshooting guide

Possible causes and solutions for the fault phenomenon

CPU power LED not lit, power supply missing or reversed polarity; Measure the voltage of the power terminal (AC or DC) when the power module is damaged, and check the fuse