Epi2 Dpv1 Power-Up - Emerson Keystone OM9 Installation & Maintenance Instructions Manual

Keystone OM9 - EPI2 PrOfIbus DPV1 IntErfacE
InstallatIon & MaIntenance InstructIons
the EPI DPV1 interface takes its electrical
2
supply from the actuator power supply module.
the rs485 bus transceiver is isolated from the
actuator electronics. also the voltage supply of
the bus termination is isolated.
the bus termination is a crucial component to
ensure error-free operation: since the Profibus
terminations are active circuits it is important
that they remain powered also when a part
of the field is powered off. normal practice
recommends to use external terminations
available on the market and to power them by a
separate, safe power supply.
the EPI DPV1 interface is equipped with an on-
2
board bus termination that can be used when
the actuator is at the beginning or at the end of
the bus segment. If the on-board termination
is used, it is not possible to use external
termination as well. the bus termination can
be connected on the data lines by means of a
soldering pad.
the figure below shows the typical Profibus
wiring. the termination must be linked to the
data lines only if the actuator is at the beginning
or at the end of the bus segment.
epi dpV1
2
interface
Data line +
Profibus
rs485
transceiver
Data line -
DGnD
9 epi dpV1 interface poWer-up
2
On power-up the module checks the baud
rate and then waits for the 'parameterization'
telegram from the master. the
parameterization message contains user
information needed for actuator operation and
is listed in chapter 8: Data exchange during
parameterization'.
after parameterization the module waits for the
'configuration' telegram from the master. the
configuration message contains the number
of input and output bytes reserved in the
memory of the master device for each slave.
Only the number of bytes determined in the
configuration is transmitted between master
and slave. this information is called 'module'.
the EPI
DPV1 board implements the following
2
modules:
• Module 1: 1 byte output; 2 bytes input
• Module 2: 4 byte output; 6 bytes input
• Module 3: 1 byte output; 2 bytes input -
consistent
• Module 4: 4 byte output; 6 bytes input -
consistent
VP
390 ohm
220 ohm
soldering pad
390 ohm
terminal
board
rx/tx-P-in
rx/tx-P-out
rx/tx-n-in
rx/tx-n-out
shield
bus out bus in
consistent is an attribute that specify the
capability of the module to maintains data
consistency over the entire data length. In this
way the data will not change during the reading
by the Profibus DP-Master.
for example, if module 2 is selected, the output
telegram consists in 4 bytes, and the input
telegram in 6 bytes.
When parameters and configuration are
correct, the module enters in 'data exchange
mode' and starts with normal operation. the
master cyclically sends commands to the slave
and read its status.
the figure on the left shows the power-up flow
diagram of a DP slave.
Power on
Wait
parameterization
Wait
configuration
configuration
not OK
slave fault
Data exchange
code
set slave
address
check
parameters
Parameterization
correct
check
configuration
configuration
correct
cyclic data
exchange
14