Performance

Original instructions

Impact on Task Cycle Time

The impact of the broadcasting on the cycle time is as follows:

Task	Typical
CANopen inputs	xx μs/PDO
CANopen outputs	xx μs + xx μs/PDO
Diagnostics	xx μs

For more information, refer to the Modicon M580 performance characteristics.

RPI Performance

According to your configuration, you can get a message from Control Expert.

In that case, you can check that:

The data amount and RPI are compatible with the performance objective of the BMECXM modules: 2000 packets/s for all the IN and OUT connections of the BMECXM modules.
The RPI is compatible with the fieldbus period.

If not, the RPI can be increased by the . If you need determinism, you can either reduce the CANopen configuration, increase the baudrate, or increase the task period.

For more information, refer to RPI values.

SDO Performance

There is one at a time for each slave. Up to 63 SDOs can be managed in parallel according to the capacity.

SDO are sent and received in synchronisation with the PLC Mast task. Therefore, the SDO response time is linked to the period of the MAST task, to the CANopen baudrate and to the response time of the slave.

Bus Start

The CANopen bus start time depends on the number of devices.

The minimum time to start a CANopen bus is 27 seconds.

The time to configure one device is about 0.8 second.

The start time of a CANopen bus with 63 devices is about 1 minute.

Device Disconnection

The time to detect the disconnection of a device depends on the protocol configuration:

Protocol	Description
Node Guarding	The time to detect the disconnection is Guard Time * Life Time Factor
Heartbeat	The time to detect the disconnection is Node Heartbeat Producer Time + Node Heartbeat consumer Time

(process data object) An unconfirmed broadcast message sent from a producer device to a consumer device in a CAN-based network. The transmit PDO from the producer device has a specific identifier that corresponds to the receive PDO of the consumer devices.

A group of sections and subroutines, executed cyclically or periodically for the MAST task and periodically for the FAST task. A task possesses a level of priority and is linked to inputs and outputs of the controller. These I/O are refreshed in relation to the task. A controller can have several tasks.

(requested packet interval) The time period between cyclic data transmissions requested by the scanner. EtherNet/IP devices publish data at the rate specified by the RPI assigned to them by the scanner, and they receive message requests from the scanner at each RPI.

(Device type manager) Device driver running on the host PC. It provides a unified structure for accessing device parameters, configuring and operating the devices, and troubleshooting devices. DTMs can range from a simple graphical user interface (GUI) for setting device parameters to a highly sophisticated application capable of performing complex real-time calculations for diagnosis and maintenance purposes. In the context of a DTM, a device can be a communications module or a remote device on the network.

(service data object) A message used by the fieldbus master to access (read/write) the object directories of network nodes in CAN-based networks. SDO types include service SDOs (SSDOs) and client SDOs (CSDOs).

(central processing unit) Brain of an industrial manufacturing process, also known as the processor or controller. It automates a process as opposed to relay control systems. CPUs are computers suited to survive the harsh conditions of the industrial environment.