Allen Bradley InterBus Module Configuration Guide

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