Watlow Electric Gateway & DeviceNet manual Assembly

RUI/Gateway & DeviceNetTM

Configuration & Ladder Logic Example

Using an Allen-Bradley CompactLogix PLC

transfer of data to and from the PLC and EZ-ZONE®controllers via simple copy instructions in the PLC. The copy instruction also works nicely when all of the data types are not the same such as when working with 8 bit, 16 bit, and 32 bit members. The copy instruction copies the source to the destination byte for byte so there is no further conversion needed.

34.Because there are 4 entries for PM1 in the custom T to O and O to T assemblies above, that must mean that the CIP Assembly Size for gateway instance 1 is equal to four. Using the same logic, PM2 has 10 entries so the Assembly Size must be equal to 10, etc…

Gateway	CIP
	Assembly
Instance
	Size
Gtw = 1	A;nb = 4
Gtw = 2	A;nb = 10
Gtw = 3	A;nb = 2
Gtw = 4	A;nb = 4

As can be seen above, unless changed, the members that occupy any one of the 20 member locations (or wherever the gateway instance changes) will be according to the factory defaults. So, the first member of the T to O for any given gateway instance will always be PV1 regardless of where it is placed in the assembly.

35.The first member of the T to O assembly above is identified as “Device Status “. This member will always be present and explains why in step 15 that the input assembly size is shown as 84 bytes (21-32 bit words) different from the output assembly being 80 bytes (20-32 bit words).

To better understand the above status word a couple of important facts related to Standard

Bus addressing must be explained. Lets first look at valid addresses (physical & logical) for computers, RUIs, Communication cards (Masters, 0-15), and lastly, EZ-ZONE®controllers (Slaves, 16-31). The logical addresses are set by the user. Look at the table below.

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