Allen Bradley InterBus Module Configuration Guide

Allen Bradley 160-IB1 InterBus Communication Module: A Complete Engineering Practice from Installation to Troubleshooting

Introduction: Why do we need a dedicated communication module

In modern industrial automation systems, frequency converters are no longer isolated execution units, but rather intelligent nodes in the factory fieldbus network. Through fieldbus, PLC or DCS can send real-time start stop commands, speed settings, and read feedback information such as the status, current, and frequency of the frequency converter, achieving centralized monitoring and coordinated control. InterBus is a common third-party network option for Allen Bradley Bulletin 160 SSC series inverters. And the bridge that realizes this connection is the protagonist of this article - the 160-IB1 InterBus communication module.

This module is designed specifically for 160 SSC series C-type and above frequency converters, providing a direct digital link to connect the InterBus master station (such as SST-IBS-SLC scanner) with the frequency converter. This article will comprehensively introduce the engineering application of the 160-IB1 module from installation wiring, parameter configuration, data protocol, control implementation to troubleshooting, helping on-site engineers quickly master its usage skills.

Key points for hardware installation and wiring

1. Safety preparation and tools

Before starting any operation, the following safety steps must be followed:

Disconnect the main power supply of the frequency converter (R, S, T/L1, L2, L3) and wait for sufficient time for the internal high-voltage capacitors to discharge (refer to the specific time in the 160 SSC user manual).

Confirm that the frequency converter has been correctly installed and connected to the motor. During the initial debugging, it is recommended to disconnect the motor from the mechanical load to prevent accidental operation.

Prepare a 3.2mm (1/8 in) flat head screwdriver for module installation and terminal wiring.

ESD (electrostatic discharge) sensitive component warning: The module contains electrostatic sensitive components inside, and anti-static measures must be taken during installation, testing, or maintenance (such as wearing a grounded wristband and using an anti-static workbench).

2. Remove the original keyboard or panel

If the program keyboard module or ready/fault indicator panel is installed on the frequency converter, it needs to be removed first:

Insert a small screwdriver into the slot above the module, gently pry it up and turn the module outward to avoid bending the bottom contact pins.

3. Install the 160-IB1 module

Confirm that the locking buckle at the bottom of the module is in the "upward" unlocked position.

Align the 30 pin connector on the back of the module with the expansion port on the front cover of the inverter and gently insert it.

Press down on the module until both sides are flush with the top surface of the frequency converter, then press down on the locking buckle and hear a "click" sound to install it in place.

4. Grounding and control terminal wiring

There is a grounding terminal at the bottom of the module (see Figure 3.4), which must be securely connected to the signal common terminal (terminal 3) of the TB3 terminal board of the inverter using a 1.5 mm ² wire. This connection is crucial for meeting EMC anti-interference requirements.

Stop input (Terminal Block 3, pins 7 and 8): Regardless of which control mode is selected, there must be a closing signal between these two terminals. It can be short circuited with wires or connected in series with a normally closed stop button. If the input is stopped and there is an open circuit, the frequency converter will report a fault and cannot be started through the network.

5. Communication cable connection

The InterBus network uses a 9-pin D-Sub connector. The 160-IB1 module has an "IN" socket at the bottom and a "NEXT" socket on the front (for cascading the next device).

Cable wiring: Use shielded twisted pair and wire according to Figure 3.6 (color may vary by manufacturer). Typical allocation: DO1+and DO1- correspond to positive and negative signals.

Insert the D-sub plug of the cable into the "IN" interface of the module and tighten the screw.

If this machine is the last device on the network, the "NEXT" interface must be empty (no terminal resistor is required, InterBus automatically handles it).

Attention: For easy observation of LED status, it is recommended to use a 180 ° straight plug (instead of a 90 ° elbow).

Variable frequency drive parameter configuration (key steps)

After module installation, several parameters of the 160 SSC frequency converter must be correctly set to receive control logic and speed settings from the InterBus network. The following parameters must be set according to the table:

Recommended parameter names and setting instructions

P46 [Input Mode] 2 or 6 2=Network control only (TB3-7/8 short circuit required); 6=2-wire TB3 control/keyboard or network optional (switched through TB3-7/8 switch). After modification, power off and restart or reset with P56=2.

P59 [Frequency Select] 1 Select the frequency command source as the internal frequency (i.e. P58, but the speed reference provided by InterBus will be used for network control).

P66 [RPM Scaling] is used to convert the speed value (RPM) sent by the network into the output frequency of the frequency converter based on the motor nameplate calculation. Calculation formula:

P66=required speed/frequency at which the speed is reached

For example, if a 4-pole motor synchronizes at a speed of 1500 rpm at 50Hz, then P66=1500/50=30.0.

Note: When operating through the network, the actual value written to P66 should be 10 times the above value (i.e. 300). If P66=0, the network speed reference is directly sent in units of 0.1Hz (e.g. 405 represents 40.5 Hz).

Important note: P66 is also the set value for [Reset Frequency 5] inside the frequency converter. Therefore, using a preset frequency of 5 by controlling the terminal may result in unexpected changes in speed. It is strictly prohibited to use P66 for both network speed scaling and terminal preset frequency functions simultaneously.

Regarding stopping input: Regardless of whether P46 is set to 2 or 6, in order to start the inverter through the network, the TB3 terminals 7-8 must be closed. This is part of the hardware security chain. If a local emergency stop is required, a normally closed stop button can be connected in series in the circuit; If only controlled through the network, it will be directly short circuited.

InterBus Data Protocol and DRIVECOM 20/21

The 160-IB1 module follows the DRIVECOM 20 (and some parts of DRIVECOM 21) specification and uses two independent data transmission channels:

Process data channel (cyclic I/O): periodic transmission of control words, speed setpoint and status words, speed feedback, diagnostic information, a total of 3 words (3 for input and 3 for output). This is the fastest real-time control path.

Parameter Data Channel (PCP Message): Non periodic transmission, used for reading and writing frequency converter parameters, attributes, fault codes, etc. Slow speed, but capable of completing configuration and diagnostic tasks.

1. Control word and status word (bit definition)

Control word (master station → slave station, register 0) - following DRIVECOM 20:

Position name function

0 Switch on 1=Connected

1 Disable voltage 0=Disable voltage

2 Fast stop 0=Quick stop

3 Enable operation 1=Enable operation

7 Reset fault 0 → 1 Rising edge reset fault

Typical control sequence for starting the driver:

Enter Ready to Switch On state: Control word=0x06 (binary 0000 0110)

Start running: Control word=0x0F (binary 0000 1111), which means both bit0 and bit3 are set simultaneously.

Key bits of the status word (slave station → master station, register 0):

bit0 Ready to switch‑on

bit1 Switched‑on

Bit2 Operation enabled (1 during operation)

Bit3 Fault (fault 1)

bit10 Speed reference reached

Bit15 Direction (1=Reverse)

2. Process data mapping

Register direction content

0 output control word

1. Output speed reference (unit RPM, scaled according to P66)

2 Output Diagnosis (Reserved)

0 input status word

1. Input actual speed (RPM)

2 Input Diagnosis (Reserved)

For example, if P66=300 (corresponding to 30.0), the input speed feedback value is directly the RPM of the motor shaft (multiplied by the gear ratio after considering the gearbox). The output speed reference is also sent in the same proportion.

3. Drive state transition diagram

In order to correctly start and stop the drive, control words must be sent according to the finite state machine shown in Figure 5.1. Main conversion:

Disable voltage (high priority stop): Control word bit1=0

Shutdown: Control word bit0=0 and bit3=0

Enable operation: From the "Ready to Switch On" or "Switched On" state, send bit0=1 and bit3=1

Fault reset: Control word bit7 generates a 0 → 1 transition

The method of bypassing the state machine: In practical applications, many engineers directly send 0x0F (start) and 0x06 (stop). But a more rigorous approach is to first send 0x06, read the status word to confirm bit0=1, and then send 0x0F.

Using PCP message to read and write parameters

Through the Parameter Channel (PCP) of InterBus, any parameters, attributes, and fault codes of the frequency converter can be read and written. PCP messages are buffered through M0/M1 files of the main station (such as SST-IBS-SLC card).

1. Parameter index

Parameter Type Index Subindex Access

P01-P20, P30-P84 read 0x5FF0 1-99 read

P30-P84 Read default value 0x5FF1 1-86 Read

Read low limit 0x5FF2 1-86 read

Read high limit 0x5FF3 1-86 read

Read attribute 0x5FF4 1-86 Read

Write parameter 0x5FF9 1-86 Write

Fault code 0x603F - Read

2. Attributes

Each parameter has an attribute word, with the high byte representing the unit (scaling) and the low byte representing the parameter number. For example, the unit of parameter 30 (acceleration time) is 0.01 seconds, and the attribute high byte 2 (see specification table 5F).

3. Write parameter examples (hexadecimal)

The following example uses the M0 file of the SST IBS SLC card to write parameter 30 (Accel Time 1) to the value 0x50 (80, which is 0.80 seconds):

Output buffer (M0 offset) data: 2 5FF9 1E 2 50

Character 0: CR=2 (the first slave station in the network)

Word 1: Index 0x5FF9 (write parameter)

Word 2: Sub index 0x1E (parameter 30)

Word 3: Number of bytes to be written=2 (two bytes)

Word 4: Written data=0x50

Input buffer (M1 offset) returns: 4 4 2 0 2 11E... - indicates success (result code 0), and parameter properties are read back (0x011E).

4. Example of reading parameters (reading parameter 8- radiator temperature)

Send: 2 5FF0 8 0... (index 0x5FF0, sub index 8)

Return: 4 4 2 0 2 45 .. - Data 0x45=69, indicating that the radiator temperature is below normal (typically below 69 ° C).

5. Pay attention to error codes: If parameter access fails, a non-zero error code will be returned, such as parameter value exceeding limit (error 4), driver running during write operation (error 10), invalid parameter number (error 20), etc. We need to check the conditions and retry.

Integration example: SLC500+SST IBS SLC scanner

In order to effectively control 160-IB1, it is common to use Phoenix IBS CMD software to configure the InterBus network and write a ladder diagram in RSLogix500.

1. Network configuration (IBS CMD)

Create a new project and set the communication path (e.g. COM19600 baud, connect to SST scanner).

Select the scanner type as "IBS USC (4K)".

Execute 'Configuration frame' → 'Read in' to automatically detect devices on the network. You should be able to see a node labeled "DRIVECOM assembly" (library ID 227).

In "Parameterization", select "Startup without PDP" and cancel "start data transmission".

After saving the configuration, the BA LED of the module should turn green and remain on.

2. I/O memory mapping

The scanner is located in slot 3 of the SLC rack. According to the address monitor, the output data starts at O: 3.0 and the input starts at I: 3.0.

Output 3 words: O: 3.0=control word, O: 3.1=speed reference, O: 3.2=diagnosis.

Enter 3 words: I: 3.0=status word, I: 3.1=speed feedback, I: 3.2=diagnosis.

3. Ladder diagram control logic

In SLC, use the MOV instruction to transfer control words (such as 16 # 000F) to O: 3.0 and speed reference (RPM value) to O: 3.1.

Read the status bit of I: 3.0 to determine whether the driver is ready, running, faulty, etc.

Fault reset: Set bit 7 of O: 3.0 from 0 to 1 and then clear it to 0 (for example, by using a timer to complete the pulse).

4. PCP parameter reading and writing program segment

Configure the G file for SST scanner: Set the length of the M file to 384 words and the length of the G file to 7 words. In G file data, Word1 bit12=1 (PCP enabled), Word5=225 (M file separation point), Word6=command buffer size.

In the ladder diagram, use the COP instruction to copy the 10 words starting from N7:70 to M0:3.225 (output PCP request), and then set the trigger bit for the scanner to process; After completion, copy M1:3.225 back to N7:80 to read the response.

Analyze the result code and data in the response according to the protocol.

Troubleshooting and Common Problems

1. Diagnosis of LED indicator light

Solution to the Meaning of LED Color Status

RC yellow light=input cable connection is normal. If it is off, check if the power supply, network cable, and previous device are online.

BA green light=bus activation/data exchange off: Check the configuration of the InterBus master station to ensure that the network is started.

TR green flashing/on=PCP communication active. If it is off and parameter access is required, check the PCP initialization settings of the main station.

RD red light=Remote bus disabled (output cable missing). If the local machine is a network endpoint node, this is normal; Otherwise, check the cable and reset the main station.

FLT red light=drive fault read fault code (P07 or Object 603F), handle according to the following table.

2. Common driver fault codes (partial)

Fault code (decimal) description and solution

03 Check the input power supply for power failure to ensure stable voltage.

04 Under voltage as above, or check the DC bus capacitance.

05 Extend deceleration time due to overvoltage, or install a braking unit.

07 Motor overload reduces load and prolongs acceleration time.

12. Overcurrent check for output short circuit and motor insulation.

38-40 short circuit to ground (U/V/W) inspection of motor and cable insulation.

41-43 output phase to phase short circuit check output wiring.

46. Intermittent phase loss inspection for external short circuits or motor windings.

3. Network communication error codes

Error code description and solution

7510 serial interface timeout confirmation: The frequency converter is of type C or above. Check if the 30 pin connector is securely plugged in and if the parameters P46/P59 are set correctly.

There is no activity on the 7520 bus. Check the InterBus cable, reset the master station, and confirm that the module is connected to the bus (IN port).

The 5000 drive model invalid frequency converter must be 160 SSC series C type or higher version.

4. Invalid parameter modification

If the modification of P46 does not take effect, it needs to be powered on in a loop or reset using P56=2.

When writing parameters, if the driver is running and the parameters are not allowed to be modified online, error code 10 will be returned (the driver is running when attempting to write parameters). Need to stop driving first.

5. The control word cannot start the driver

Confirm that TB3-7/8 is in a closed state (stop input).

Read status word: bit0 and bit1 must be 1, and bit2 must be 0 to enter operation.

According to the state transition diagram, send 0x06 first, then 0x0F. Do not jump directly from 0x00 to 0x0F.

Summary of Technical Specifications

Project specifications

The power supply is provided by a frequency converter, with a maximum power consumption of 1.4W

Working temperature 0~65 ° C

Storage temperature -40~+85 ° C

Relative humidity 0~95%, no condensation

Communication rate 500 kBaud (fixed)

Protocol DRIVECOM 20/21, InterBus PCP

See Appendix A for dimensions (in millimeters)

Suitable for frequency converter 160 SSC series C type and above