ABB Pluto Safety PLC Maintenance and Troubleshooting

Working voltage: 24 V DC ± 15% (approximately 20.4-27.6 V).

Recommended external fuses: S20/A20/B16/B20 use 6A; S46/B46 use 10A.

Electrical insulation category: Class II (compliant with IEC 61010-1).

The current consumption of all safe inputs I and IQ is 5.1 mA (at 24V), with a maximum withstand overvoltage of 27V continuously.

3.3 Example of Dynamic Signal Series Connection

Connect single channel dynamic Eden sensors (multiple in series):

Pluto's T0 or T1 terminals output dynamic signals (A pulses).

The input of the first Eden is connected to a dynamic signal, and the output is connected to the input of the next Eden in series.

The output of the last Eden returns to Pluto's I input terminal.

Configure the input as the corresponding dynamic signal type (such as A pulse) in Pluto Manager.

Connect Tina adapter (for emergency stop button, safety switch):

Tina adapter can convert mechanical contacts into dynamic signals. Also supports up to 10 serial connections.

Connect the dual channel static switch:

Use two I inputs and connect 24V signals to two contacts respectively. Configure as dual channel equivalent in the program.

3.4 Bus Terminal and IDFIX

Pluto bus: using CAN bus, with a speed of 100-1000 kbit/s and a maximum line length of 600 m (150 m at 400 kbit/s). Both ends of the bus need to be connected to terminal resistors R-120 (order number 2TLA020070R2200).

IDFIX: Used to assign a unique address to each Pluto. There are four versions: R (read-only address), RW (programmable address), DATA (including AS-i security code), and PROG (used for single Pluto program storage/recovery). IDFIX is connected between the ID terminal and 0V.

Pluto Manager Programming and Configuration

Pluto Manager is a free software that can be downloaded from ABB's official website and supports ladder programming and T Ü V certified functional blocks.

4.1 Three step project approach

I/O configuration: Define the signal type (static/dynamic A/B/C, inverted or not) and IQ direction (input/output/bidirectional) for each I and IQ terminal.

Variable naming: Assign symbol names to input (I), output (Q), hold memory (M), global bus memory (GM), and register (R).

Ladder diagram programming: Build safety logic using functional blocks such as TC1RTI dual channel monitoring, dual manual control, mute, timer, etc.

4.2 Examples of Key Function Blocks

TC1RTI (Block 3): Dual channel safety input with test input, reset input, and reset indication. When the function block is ready and waiting for reset, the IndReset output flashes; TCfault is activated when there is a dual channel fault.

Two manual controls (Block 16): used for NO/NC contact pairing, requiring simultaneous action of the left and right four inputs within 0.5 seconds, and correct standby state (right_de0=0, right_nC=1, left_de0=0, left_nC=1).

Silent light monitoring: Block 20/21 is used for silent lights (Q16/Q17), while Block 22/23 supports power settings (watts).

Safety encoder: used for single or multi turn absolute encoders to generate safe position and velocity values, with dual encoder differential monitoring (MaxDiff ≤ 2%).

4.3 Program Download and Bus Distribution

Connect any Pluto unit through a programming cable (RS232 or USB).

After compiling the project in Pluto Manager, select 'Download'. The program will automatically distribute to all other Pluto units in the network through the Pluto bus, and each unit will extract the corresponding logic based on its configuration.

The IDFIX ROG can also be used to copy programs in a single Pluto system: connect the IDFIX ROG to the ID terminal, and the program will be automatically written after power on.

Fault diagnosis: LED and system registers

5.1 Hardware Status LED

The Pluto unit front panel provides multiple LEDs for quick status determination:

Meaning of LED color

Power green power supply is normal

Run green program

Error Red System Error (such as watchdog, bus failure)

Bus yellow (flashing) Pluto bus communication activity

I/O red/green specific I/O point status (defined after configuration)

5.2 System registers and user errors

Pluto has a 7-segment display (located on the front panel of models A20/B20, etc.) that can display error codes. The user program can display custom error codes (200-299) by writing to system register 11 (SR11).

Common error code meanings:

Alarm 01: Emergency stop button triggered

Alarm 02: Door open

Alarm 03: Machine hatch open

These codes can be written into SR11 and displayed on a 7-segment screen. System register 11 will prioritize displaying Pluto's own errors (such as bus faults) before displaying user-defined errors.

5.3 Troubleshooting of Bus Communication Malfunctions

Check if the terminal resistor is installed (only at both ends of the bus).

Check if the bus cable is a dedicated CAN bus cable (yellow, 2 × 0.50 mm ², model 2TLA020070R3000).

Using a gateway (GATE-D2/C2) as a bridge can filter unnecessary bus data and extend communication distance.

When there is an error, the bus response time will increase by 10-40 ms.

5.4 Handling of Safety Output Malfunctions

The transistor output (Q2, Q3) is -24 VDC (negative output), mainly used to control contactors and valves. This unique potential helps detect short circuits to ground or with other potentials.