York AYK 550, User Manual

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152 AYK550-UH User’s Manual
Serial Communication – EFB
Faults 31…33 – EFB1…EFB3
The three EFB fault codes listed for the drive in "Diagnostics" starting on page 212
(fault codes 31…33) are not used.
Intermittent Off-line Occurrences
The problems described above are the most common problems encountered with
AYK550 serial communication. Intermittent problems might also be caused by:
• marginally loose connections,
• wear on wires caused by equipment vibrations,
• insufficient grounding and shielding on both the devices and on the
communication cables.
Modbus Protocol Technical Data
Overview
The Modbus® protocol was introduced by Modicon, Inc. for use in control
environments featuring Modicon programmable controllers. Due to its ease of use
and implementation, this common PLC language was quickly adopted as a de-facto
standard for integration of a wide variety of master controllers and slave devices.
Modbus is a serial, asynchronous protocol. Transactions are half-duplex, featuring a
single Master controlling one or more Slaves. While RS232 can be used for point-to-
point communication between a single Master and a single Slave, a more common
implementation features a multi-drop RS485 network with a single Master controlling
multiple Slaves. The AYK550 features RS485 for its Modbus physical interface.
RTU
The Modbus specification defines two distinct transmission modes: ASCII and RTU.
The AYK550 supports RTU only.
Feature Summary
The following Modbus function codes are supported by the AYK550.
Function Code (Hex) Description
Read Coil Status 0x01 Read discrete output status. For the AYK550, the individual bits
of the control word are mapped to Coils 1…16. Relay outputs are
mapped sequentially beginning with Coil 33 (e.g. RO1=Coil 33).
Read Discrete Input
Status
0x02 Read discrete inputs status. For the AYK550, the individual bits of
the status word are mapped to Inputs 1…16 or 1…32, depending
on the active profile. Terminal inputs are mapped sequentially
beginning with Input 33 (e.g. DI1=Input 33).
Read Multiple
Holding Registers
0x03 Read multiple holding registers. For the AYK550, the entire
parameter set is mapped as holding registers, as well as
command, status and reference values.
Read Multiple Input
Registers
0x04 Read multiple input registers. For the AYK550, the 2 analog input
channels are mapped as input registers 1 & 2.
Force Single Coil 0x05 Write a single discrete output. For the AYK550, the individual bits
of the control word are mapped to Coils 1…16. Relay outputs are
mapped sequentially beginning with Coil 33 (e.g. RO1=Coil 33).