Western Reserve Controls, Inc.
1782-JDO User’s Manual
PRELIMINARY
20
5.1 Setting up Serial Communications
5.1.1 Reading the Data Frame Format
The data frame format parameter defines the size of the data frame that is transmitted and
received over the serial link. This parameter defines the number of data bits per character (7
or 8), the parity (odd, even or none) and the number of stop bits (1 or 2). Optomux
brainboards support 8N1 only. This parameter provides an affirmation of this value in the
JDO.
5.1.2 Setting up the serial link baud rate
The standard baudrates are supported by the JDO, starting at 1200 baud and going to 38400
baud. The baudrate is configured at parameter 2 of the parameter object. The valid options
are:
Table 5-2
Serial Baud Rates
Value
Baud Rate
0
9600
1
1200
2
2400
3
4800
4
19200
5
38400
5.2 Setting up DeviceNet Communications
The 1782-JDO supports Polled I/O only.
5.2.1 Polled I/O
The polled connection is the only manner in which you can send serial output data to the JDO
and, therefore, to your ASCII device. The DeviceNet Master initiates the polled connection
by sending Poll Command data to the JDO for the B1’s and the JDO responds with data from
the B1’s.
5.2.2 Reading the I/O Poll Response Data Size
This is the number of bytes that the JDO will send to the DeviceNet Master from the B1(s)
and is determined by:
produce_size = number_of_B1s * 3 (+1 if the number of B1’s is odd)
This number is calculated by the JDO. The valid settings for this value are 4-60. The default
value is 4. This produce_size is used to set up the Poll Receive size at your Master device.
These values can be retrieved by using the standard get service on class 15 (F
hex
), instance
5, attribute 1 (See Table 5-1).
Note: The number of bytes in the response message will always be even, due to
padding which takes place when the number of brainboards is odd. This is due to the
fact that PLCs are 16 bit or 32 bit word length as formatted in memory.
