Nordson iControl - Sending Messages from the PLC

iControlr PROFIBUSr, PROFINETr, DeviceNett, and EtherNet/IPt Generation 4 Slot 9 Gateway
18
Part 1605930−02
E 2020 Nordson Corporation
CommentRangeDescriptionSize
(Bytes)
Address
Offset
IO Module
No.
16 59 1 Paged Gun #2−
Low Byte
0−255 Low Byte Information
16 60 1 Paged Gun #2−
High Byte
0−255 High Byte Information
16 61 1 Paged Gun #3−
Low Byte
0−255 Low Byte Information
16 62 1 Paged Gun #3−
High Byte
0−255 High Byte Information
16 63 1 Paged Gun #4−
Low Byte
0−255 Low Byte Information
16 64 1 Paged Gun #4−
High Byte
0−255 High Byte Information
Sending Messages from the PLC
Two general methods can be used to prevent the Gateway from translating
a partially constructed message send by the PLC master. The Single Scan
Method is the most efficient, but if the two conditions cannot be met, then
the Multiple Scan Method should be used.
See Figure 6 for a diagram of the messages being sent.
Single Scan Method
For most PLCs the single scan method can be done with multiple
instructions executed in one scan cycle.
1. Set all bytes in the IO module to be written using one PLC instruction (all
data is written in one IO scan).
2. Synchronize the PLC fieldbus master to the IO scan.
Multiple Scan Method
The multiple scan method applies to masters in the PC-based control
system or in PLC systems where the fieldbus master scans asynchronously
with the PLC IO scans.
1. Set the first byte of the IO module to zero (WAIT) before the rest of the
IO module is set-up.
2. The remaining IO bytes of the IO module can be written as the first byte
remains at zero.
3. When writing of the remaining bytes is complete, go back and write the
first byte from the zero (WAIT) to its correct value.