Communicate Through The Adapter; Map The Data; Overview Of The Communication Process - Parker H Series Installation & Service Instructions Manual

2-8 What is the H Series Fieldbus DeviceNet Adapter?

Communicate Through the Adapter

As described previously in this manual, the adapter resides on the
DeviceNet network and the PointBus simultaneously. The adapter's
functions are as follows:
• DeviceNet – adapter serves as a slave device that exchanges
I/O data with another DeviceNet scanner device (e.g., 1771-
SDN) via DeviceNet messages
• PointBus – adapter serves as master for up to 63 I/O modules,
using DeviceNet messages to consume from or produce data
to each module.
IMPORTANT
If Automatic Device Replacement (ADR) is enabled on the
adapter, you can only connect up to 62 modules via the PointBus.
For more information on ADR, see page 2-6.

Map the Data

Your adapter must store data temporarily before transferring it
between devices. You must map data to your adapter's memory
before transferring it.
For a detailed description of the mapping process, see page 2-9.

Overview of the Communication Process

In a typical confi guration, the adapter acts as an interface between
a DeviceNet scanner (e.g., Rockwell Automation 1756-DNB) and H
Series Fieldbus I/O modules. The following example graphic shows
information transferred from a 1756-DNB to H Series Fieldbus I/O
modules.
IMPORTANT
Although information is exchanged between the Logix5555 and
1756-DNB, this diagram (nor this chapter) is not designed to
explain such an exchange.
Four data transfers are shown in the diagram, including:
1. Scanner to adapter
2. Adapter to I/O modules
3. I/O modules to adapter
4. Adapter to scanner
Because the adapter simultaneously resides on the DeviceNet
network and on PointBus, it serves as a slave to the processor (i.e.,
steps 1 and 4) and a master to the I/O modules (i.e., steps 2 and 3).
The four data transfers are not necessarily sequential. Transfers 2
and 3 typically occur more frequently than transfers 1 and 4.
Publication PSS-UM001A-EN-P – December 2016
Computer with PLC
Programming Software
ControlNet Network
Logix5555 Controller
The Logix5555 controller sits in the backplane.
The 1756-DNB contained in the controller
communicates with the H Series Fieldbus adapter.
1784-PCD
PCMCIA Card
DeviceNet Network
PSSN8M12A
PSSCDM12A
24V dc In
0 2
DeviceNet Out
Adapter
1 3 MOD
Status
DeviceNet In
DeviceNet
NET
Status
PointBus
0
Status
1
System
0 0 2
Power
8 2 8 2
Adapter
3
4 6
Power
6 4 6 4
x10 x1
4
5
5 7
6
7
PWR
H Series Fieldbus
I/O Modules
PSSCDM12A
Adapter
The computers and PCMCIA card shown in the diagram are required
to confi gure the processor, adapter, and I/O modules.
Although the PCMCIA card is used in this example, you can use other
communications cards, such as PCID and KFD cards.
Key Points About Scanner to Adapter Transfer (Step 1)
1. Scanner initiates transfer
2. Scanner uses DeviceNet I/O messaging to write data to adapter.
Data may contain:
• device output data
• confi guration data
Key Points About Adapter to Output Module Transfer (Step 2)
1. Adapter initiates transfer
2. Adapter produces data for I/O module to consume.
Data may contain:
• device output data
• confi guration data
Key Points About Input Module to Adapter Transfer (Step 3)
Adapter consumes data I/O module has produced.
Data may contain:
• device input data
• status data
Key Points About Adapter to Scanner Transfer (Step 4)
SDN consumes I/O data produced by adapter.
Data may contain:
• device input data
• status data
Computer with
RSNetWorx for
DeviceNet
Software
PSST8M12A
PSSV32A
24V dc Out
0 2
1 3 MOD Mod
NET Net
0 Fault
1
2
3
4 6
4
5
5 7
6
7