Detailed Description Of Services; Read From Variable Area - Omron EJ1 User Manual

Detailed Description of Services

6-4

Detailed Description of Services

6-4-1

Read from Variable Area

174
This service reads from a variable area.
■ Command
Service Request PDU
Variable
MRC SRC
type
0 1 0 1
2 2 2
■ Response
Service Response PDU
Response
MRC SRC
code
0 1 0 1
2 2 4
1. Variable Type and Read Start Address
Refer to Parameter List on page 233.
2. Bit Position
The EJ1 does not support bit access. Fixed to 00.
3. No. of Elements
Read data length
For double-word (8-digit) variable type
For word (4-digit) variable type
Note The following values apply for the DA/9A variable types.
Read data length
For double-word (8-digit) variable type
For word (4-digit) variable type
4. Response Codes
Response code
1001 Command too long
1002 Command too short
1101 Area type error
110B Response too long
1100 Parameter error
7011 Operation error (7011) The command cannot be executed due
0000 Normal completion
5. Precautions
• "0" is set when an address with no data set is read.
• If the start address + number of elements exceeds FFFF, the address
returns to 0000.
Bit No. of elements
Read start
position
address
0 0
4 2
Read data
(for No. of elements)
No. of elements 8 or 4
Error name
The command is too long.
The command is not long enough.
The corresponding variable type does
not exist.
The number of elements exceeds the
maximum.
Bit position is not 00.
to a device error.
Processing was completed normally.
Section 6-4
4
No. of elements
40 max. (0028H)
80 max. (0050H)
No. of elements
25 max. (0019H)
50 max. (0032H)
Cause