User`s manual

Western Reserve Controls, Inc. 1782-JDC User’s Manual

5.1 Setting up Serial Communications

5.1.1 Setting up the serial link baud rate

The standard baud rates are supported by the JDC, starting at 1200 baud and going to 38400

baud. The baud rate 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

5.1.2 Setting up the receive delimiter

The receive delimiter is an end-of-string character. It is used by the JDC to determine that

the last expected character from the ASCII device has been received. Upon receipt of this

character, the JDC updates its internal data buffer on the serial receive side and transmits this

new string to the DeviceNet system. It is also used by the DeviceNet sections of the device to

determine when the device should generate a COS triggered message over the DeviceNet

network, if COS has been selected. The receive delimiter can be set to any valid ASCII

character that can be received over the link. Be very careful not to set the delimiter to a value

outside of the valid range for your data bits (Note: A data bit size setting of 7 will only allow

you a delimiter range of 0-127 dec., 00-7F

hex

). If you do not have a valid receive delimiter, or

the receive delimiter is never received, the device will only update the output buffer on

detection of an overflow condition, that is, when it has received the number of characters

defined in max_number_of_receive_chars, defined in Parameter 5.

These values can be set and retrieved by using the standard set and get services on class 15

hex

), instance 3, attribute 1 (See Table 5-1).

5.1.3 Setting up the transmit delimiter

The transmit delimiter is an end-of-string character which is used by the JDC to determine

how many bytes to transmit over the serial link to your ASCII device. If the buffer length is not

0 the JDC will ignore the transmit delimiter. The JDC will transmit up to and including the

delimiter when the above condition is met. The transmit delimiter can be set to any valid ASCII

character that can be received over the link. Be very careful not to set the delimiter to a value

outside of the valid range for your data bits (Note: A data bit size setting of 7 will only allow

you a delimiter range of 0-127 dec., 00-7Fhex). If you do not have a valid delimiter, or the

delimiter is never received, the device will only update the output buffer on detection of an

overflow condition.

These values can be set and retrieved by using the standard set and get services on class 15

hex

), instance 4, attribute 1 (See Table 5-1).