Explicit Messaging on DeviceNet™ 6-5
Sequence of Events Use the following sequence of events as a guide for establishing
explicit messages in your SLC ladder logic.
1. Put the explicit message request data into an integer (N) file of the
SLC-500 processor.
2. Use the file copy instruction (COP) to copy the explicit message
request data entered in step 1 to the M0 File, words 224 through
256.
3. Use the examine-if-closed instruction (XIC) to monitor bit 15 of
the scanner’s module status register for an indication that it has
received a response from the ArmorStart.
4. Copy the data from the M1 file, words 224 through 256, into a file
in the SLC-500 processor using the file copy instruction (COP).
The following example shows the exact data format to perform a
“Get Attribute Single” request. This message will specifically access
parameter 104, Average Current. The first three words are shown
segmented into two bytes, corresponding to the upper and lower bytes
shown in the explicit message request table (Table 6.4).
Note: The data in the table is shown in a hexadecimal format.
Therefore parameter 104 decimal is equal to 68 hexadecimal
(0x68).
Table 6.7 Get_Attribute_Single Request
Table 6.8 Get_Attribute_Single Response
Figure 6.2 SLC Example of Ladder Logic Program
TXID Command Port Size Service MAC ID Class Instance Attribute
Word 0 1 2 34567
N7:x 01 01 00 06 0E 04 000F 0068 0001 — —
TXID Status Port Size Service MAC ID Data
Word 10 11 12 13 14 15 16 17
N7:x 01 xx 00 06 0E 04 x — — — —
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