1
INSTRUCTION BULLETIN—Reference Guide
CyTime
TM
Sequence of Events Recorder
IB-SER32e-02
Jan-2022
© 2010-2022 Cyber Sciences, Inc. All rights reserved.
1—ETHERNET COMMUNICATIONS
The CyTime
TM
SER-32e Sequence of Events Recorder supports the following Ethernet
protocols:
●
Hypertext Protocol Secure (HTTPS): HTTPS is a networking protocol used
by web browsers to access and present data over a secure network. The
CyTime SER uses HTTPS to provide secure web server functionality using TLS
version 1.3 with 256-bit encryption over TCP port 443 (default).
●
Modbus TCP: Modbus TCP is a combination of the Modbus protocol, which
provides master-slave communication between devices, and TCP/IP, which
provides communications over an Ethernet connection. Modbus TCP can be
used by application software, PLCs, or other master devices to access data or
send commands to the SER, using TCP port 502.
Note: Connections (“Modbus TCP Sockets”) that remain idle for 75 seconds and
then fail to acknowledge after three (3) retries are closed automatically (TCP
keep-alives).
●
Network Time Protocol (NTP): NTP is a time protocol used to synchronize
clocks of networked devices to a time reference provided by an NTP time
server, using UDP port 123.
●
Precision Time Protocol (PTP): PTP, defined in IEEE Std. (1588-2008/2019),
takes advantage of special time-stamping Ethernet hardware to distribute
a precise time reference over Ethernet, ensuring time accuracies of 100 µs
or better. The PTP “grandmaster” broadcasts precise date/time and network
delay correction data to PTP slaves using UDP ports 319 (ptp-event) and 320
(ptp-general) via multicast IP address 224.0.1.129.
Ethernet Protocols Supported
The standard Modbus data model consists of four data tables, and a convention
used by most manufacturers is to add a single-digit prefix to indicate register type:
0xxxxx — Discrete Output Coils (000001 to 065536)
1xxxxx — Discrete Input Contacts (100001 to 165536)
3xxxxx — Input Registers (300001 to 365536)
4xxxxx — Holding Registers (400001 to 465536)
In this convention, register references use a 1-index, while the actual values used in
the data address field of Modbus messages are 0-based (0 to 65535). Thus, a holding
register reference number 400201 would be read with function code 03 at data
address field 0200.
In this document, all Modbus registers are expressed using this de facto convention
(single-digit prefix to indicate register type, plus offset of 1 from the data address
used in the actual Modbus message).
Modbus Addressing Conventions
Note: This instruction bulletin describes product fea-
tures and behaviors for the latest firmware version
available at the time of publication. Cyber Sciences
recommends updating to the latest firmware when-
ever feasible, available for free download: