User`s manual

DeviceNet (Master) Function
8-21
8
8-3 I/O message function
Among I/O messages of the DeviceNet, the JW-32CUM1 (DeviceNet) supports Polling I/O function and
Bit Strobe function. JW-32CUM1 (master mode) can communicate messages with slave modules having
either of these two functions.
- The Polling I/O is a method that a master module sends a command (point to point) to each slave
module and receive messages, if any.
- Bit Strobe is a message that multiple slave modules receive one command and respond using
broadcasting function. This is convenient for collecting small data such as multiple slaves devices are
arranged like sensors. Use the JW-32CUM1 with master mode, when creating a scan list, it establishes
connection with the Bit Strobe for slave modules having Bit Strobe function.
When the master mode is selected and the I/O message function in the JW-32CUM1 is used, the input/
output table addresses will be as follows.
Input/output data table addresses
(O: Enable, —: Disable) * Specify top address and select enabled or disabled.
8-3-1 Input/output table allocation
The JW-32CUM1 (master mode) can select from several allocation methods for the slave station input/
output data table. For selection, set system memory of the JW-32CUM1. The choices are "allocation in
address order," "even number allocation," and "allocation in the order in which vacant nodes are
occupied." To set the selection, use switches SW7-3 and 7-4 on the JW-32CUM1. -See page 8-9.
noitarepocisaB
edom
fo.oN
setyb
dexiF eerF
retsaM evalS
O— 215*303#ot003#
ｺ2000 to ｺ2777
Allocation
method
Input/output data table allocation details Details
Address
order
allocation
1.
2.
3.
4.
Assign data lengths (number of bytes) in node address order for slave stations.
Enter the number of bytes required by each slave station.
A slave station that does not have a I/O message function is not assigned a
data length.
Any slave station number (node address), that does not have hardware
connected is not assigned a data length.
Page 8-22
Even
number
allocation
1.
2.
3.
4.
Assign data lengths (number of bytes) in node address order for slave stations.
Enter the number of bytes required by each slave station.
For any slave station that needs more data than the default data length,
increase the size in multiples of the default number of bytes.
A slave station that does not have a I/O message function is not assigned a
data length.
Any slave station number (node address), that does not have hardware
connected is not assigned a data length.
Page 8-24
Allocation
in the
order in
which
vacant
nodes are
occupied
1.
2.
3.
4.
Assign data lengths (number of bytes) in node address order for slave stations.
Enter the number of bytes required by each slave station with a I/O message
function.
A slave station that does not have a I/O message function is not assigned a
data length.
Any slave station number (node address), that does not have hardware
connected, is assigned the default data length.
Page 8-26
- No matter which allocation method is selected, you have to start the master module JW-32CUM1 in the
scan list edit mode, collect the data from slave stations, and create a scan list. The scan list classifies
slave station inputs and outputs, data lengths, and addresses. Therefore, a separate configuration
program is not needed for the input/output data table allocation. See page 8-28 to 8-29.
- Set the default data length used in the "Even number allocation" and "Allocation in the order in which
vacant nodes are occupied" modes to 1 to 64 bytes. To set the selection, use switches SW7-5 and 7-6
and the system memory in the JW-32CUM1. - See page 8-9, 8-14.
Remarks
- Number of I/O points with the JW-32CUM1 is maximum 4096 (512 bytes).
When editing the scan list while the total number of I/O points of slave modules connected
exceeds 4096, node addresses exceeding 4096 will be ignored.