Data Format; Command Frame - Omron ZEN-8E Communications Manual

SECTION 2 CompoWay/F Communications Protocol

2.1 Data Format

For CompoWay/F, numeric values for commands are converted to ASCII and expressed as hexadecimal
values.
• Numbers prefixed with H' are hexadecimal, e.g., H'02 is 02 hexadecimal.
• The numbers below the various parts of a frame specify the number of bytes.
• Unless specified, all other numbers are ASCII characters. (Refer to the Appendix for a table of ASCII
characters.)

■ Command Frame

Node number Sub-address
STX
1
STX This code (H'02) indicates the beginning of the communications frame (text).
Always set STX in the first byte.
When STX is received again during reception, reception is carried out again from the point
where STX was received.
Node number • This number specifies the transmission destination.
• Specify the ZEN's node number.
• A BCD value between 00 and 99 or an ASCII value of XX can be set.
• Specify "XX" for a broadcast transmission. No responses will be returned for broadcast
transmissions.
• No responses will be returned from node numbers other than the ones in the above
range.
• The default setting is 01.
Sub-address The sub-address is not used in the ZEN. It must be fixed at "00."
SID • Service ID. The service ID is not used in the ZEN.
• Be sure to set it to "00."
Command text This is the command text area. For details, see 2.2 Structure of Command Text.
ETX This code (H'03) indicates the end of the text.
BCC • This is the Block Check Character.
• The BCC result is found by calculating the exclusive OR of the bytes from the node num-
ber up to ETX.
10
0 0
2 2
BCC calculation range
Text
SID FINS-mini command text
0
1
BCC
ETX
1 1