Omron EJ1G, Руководство пользователя

Страница: 153 / 237

132
Detailed Description of Services
Section 6-4
6-4 Detailed Description of Services
6-4-1 Read from Variable Area
This service reads from a variable area.
■
Command
Service Request PDU
■
Response
Service Response PDU
1. Variable Type and Read Start Address
Refer to Parameter List on page 175.
2. Bit Position
The EJ1G does not support bit access. Fixed to 00.
3. No. of Elements
Note The following values apply for the DA/9A variable types.
4. Response Codes
5. Precautions
• “0” is set when an address with no data set is read.
• If the start a number of elements exceeds FFFF, the address
returns to 0000.
MRC
2 2
0 1
4
SRC
2
0 1
2
0 0
4
Variable
type Read start
address
Bit
position No. of elements
Read data length No. of elements
For double-word (8-digit) variable type 40 max. (0028H)
For word (4-digit) variable type 80 max. (0050H)
Read data length No. of elements
For double-word (8-digit) variable type 25 max. (0019H)
For word (4-digit) variable type 50 max. (0032H)
Response code Error name Cause
1001 Command too long The command is too long.
1002 Command too short The command is not long enough.
1101 Area type error The corresponding variable type does
not exist.
110B Response too long The number of elements exceeds the
maximum.
1100 Parameter error Bit position is not 00.
7011 Operation error (7011) The command cannot be executed due
to a device error.
0000 Normal completion Processing was completed normally.
MRC
2
0 1
4
SRC
2
0 1
Response
code
Read data
(for No. of elements)
No. of elements
×
8 or 4