supporting Sequence of Events

Publication 1732E-UM002A-EN-P - March 2010
6 Module Overview
If the ring topology is used, the Ring Master (not the 1732E EtherNet/IP
ArmorBlock Supporting Sequence of Events) must be designated in the
system, and it will determine the beacon rate and the timeout period. For more
information on topologies, refer to publication ENET-AP005
. The
1732E-IB16M12SOEDR module is a CIP Sync slave only device. There must
be another module on the network that will function as a master clock.
Each input connector's Sensor Source Voltage (SSV) is protected from short
circuits to ground as well as open wire conditions due to missing sensor or
cable disconnection. These conditions are indicated in the modules input tags
and by its input LEDs flashing red for open wire or being solid red for short
circuit.
Introduction to CIP Sync
CIP is the Common Industrial Protocol that we use to let all Rockwell
products communicate with each other whether it be on a DeviceNet,
ControlNet, and/or an EtherNet network. Since it is an ODVA standard,
other industrial product manufactures develop products to communicate via
the CIP protocol.
CIP Sync is a CIP implementation of the IEEE 1588 PTP (Precision Time
Protocol) in which devices can bridge the PTP time across backplanes and on
to other networks via EtherNet/IP ports.
What is IEEE 1588 PTP (Precision Time Protocol)?
The IEEE 1588 standard specifies a protocol to synchronize independent
clocks running on separate nodes of a distributed measurement and control
system to a high degree of accuracy and precision. The clocks communicate
with each other over a communication network. In its basic form, the protocol
is intended to be administration free. The protocol generates a master slave
relationship among the clocks in the system. Within a given subnet of a
network there will be a single master clock. All clocks ultimately derive their
time from a clock known as the grandmaster clock. This is called Precision
Time Protocol (PTP).
The PTP is a time-transfer protocol defined in the IEEE 1588-2008 standard
that allows precise synchronization of networks, for example, Ethernet.
Accuracy within the nanosecond range can be achieved with this protocol
when using hardware generated synchronization.
IEEE 1588 is designed for local systems requiring very high accuracies beyond
those attainable using Network Time Protocol (NTP). NTP is used to
synchronize the time of a computer client or server to another server or
reference time source, such as a GPS.