Watlow ez-zone pm - Modbus and CIP Communication Details

Watlow EZ-ZONE
®
PMI Controller • 210 • Chapter 9 Features
Modbus - Using Programmable Memory Blocks
When using the Modbus RTU or Modbus TCP protocols, the PM control features a block of ad-
dresses that can be congured by the user to provide direct access to a list of 40 user cong-
ured parameters. This allows the user easy access to this customized list by reading from or
writing to a contiguous block of registers.
To acquire a better understanding of the tables found in the back of this manual (See Ap-
pendix: (Modbus Programmable Memory Blocks) please read through the text below which
denes the column headers used.
Assembly Definition Addresses
- Fixed addresses used to define the parameter that will be stored in the "Working Address-
es", which may also be referred to as a pointer. The value stored in these addresses will
reflect (point to) the Modbus address of a parameter within the PM control.
Assembly Working Addresses
- Fixed addresses directly related to their associated "Assembly Denition Addresses" (i.e.,
Assembly Working Addresses 200 & 201 will assume the parameter pointed to by Assembly
Denition Addresses 40 & 41).
When the Modbus address of a target parameter is stored in an "Assembly Denition Address"
its corresponding working address will return that parameter’s actual value. If it’s a writable
parameter, writing to its working register will change the parameter’s actual value. As an
example, Modbus register 360 represents the Analog Input 1 Process Value (See Operations
Page, Analog Input Menu). If the value 360 is loaded into Assembly Denition Address 90 and
value 361 is loaded into Assembly Denition Address 91, the process value sensed by analog
input 1 will also be stored in Modbus registers 250 and 251. Notice that by default this pa-
rameter is also stored in working registers 240 and 241 as well.
Note:
When modifying the Modbus Assembly registers, single register writes (function 06) are not
allowed. Multiple register writes (function 16) must be used to modify the assembly.
The table identied as "Assembly Denition Addresses and Assembly Working Addresses" (see
Appendix: Modbus Programmable Memory Blocks) reects the assemblies and their associated
addresses.
CIP - Communications Capabilities
With the introduction of the Common Industrial Protocol (CIP) a user can now collect data,
congure a device and control industrial devices. CIP is an open protocol at the application
layer fully managed by the Open DeviceNet Vendors Association (ODVA, http://www.odva.
org). Being that this is an open protocol there are many independent vendors offering a wide
array of devices to the end user. CIP provides the ability to communicate utilizing both im-
plicit messaging (real-time I/O messaging), and explicit messaging (information/congura-
tion messaging). For implicit communications using a PLC, simply congure the PM assembly
size into the I/O structure of the PLC (See: CIP Implicit Assemblie Structures). The assembly
structures can also be changed by the user. Explicit communications requires the use of
specic addressing information. DeviceNet requires that the node address be specied where
EtherNet/IP requires just the Class, Instance and Attribute.
• Node address or MAC ID (0 - 63, DeviceNet only)
• Class ID (1 to 255)
• Instance ID (0 to 255)