Watlow PM PLUS 6, Руководство пользователя

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Watlow PM PLUS™ 6 • 104 • Chapter 8: Features
Compact Assembly Class
Along with the standard implicit assembly where each module parameter (member) occupies one 32-bit as-
sembly location, there is also a Compact Class assembly. The need for the Compact Class assembly members
became apparent as the number of member instances grew with the EZ-ZONE family of controls. Because there
is a limited number of implicit assembly members (40 input, 40 output), the Compact Class enables the user
to modify the standard assembly offering to their liking while also achieving much better utilization of each bit
within the 32-bit member. As an example, if a standard Implicit Assembly member were configured to monitor
Alarm State 1, the entire 32-bit member would be consumed where just 7 bits out of the 32 represent: Startup
(88), None (61), Blocked (12), Alarm Low (8), Alarm High (7) or Error (28). With Compact Class assembly
member 12 (identified in this document as " 12 A, Alarm Read ") in use, the alarm states of all 4 alarms can be
placed in one 32-bit assembly member using just 2 bits for each state. Bits 0 and 1 would represent Alarm State
1, bits 2 and 3 Alarm State 2, etc... Each pair of 2 bits can represent the following states: 00 = None, 01 = Alarm
Low, 10 = Alarm High and 11 = Other. There is a variety of predefined Compact Class members that can be used
(See Appendix: Compact Class Assembly Structure ) to modify the default implicit assemblies.
As is the case with any available parameter within the PM control, the Compact Class members can also
be read or written to individually via an explicit message as well.
Modifying Implicit Assembly Members
To change any given member of either assembly (T to O or O to T) simply write the new class, instance and
attribute (CIA) to the member location of choice. As an example, if it were desired to change the 14 th member
of the T to O assembly from the default parameter (Cool Power) to the Compact Class 12 th member (See Ap-
pendix: Compact Class Assembly Structure ) write the value of 0x71, 0x01 and 0x0C (Class, Instance and Attri-
bute respectively
)
to 0x77, 0x02 and 0x0D. Once the change is executed, reading this member location (as was
discussed above) will return the Alarm States (1-4) to paired bits 0 through 7 where 00 = None, 01 = Alarm Low,
10 = Alarm High and 11 = Other. The CIP communications instance will always be instance 2.
PCCC - (Programmable Controller Communications Com-
mands)
This protocol is typically used with older Allen Bradley programmable controllers capable of PLC-5 compatibility.
The PM PLUS™ has 2 assemblies; one for input (O to T), and the other for output (T to O). As viewed and
accessed using Rockwell software, these PM PLUS™ assemblies can be identified as N11:0 (O to T) and N10:0
(T to O).
Refer to the Appendix: CIP Implicit Assembly Structures.
Example: If an ML1100 is used to write a new Set Point to the PM PLUS, a message instruction needs to be setup within
the PLC to send a floating point value to N11:2. Likewise, if you want to read the Analog Input Value from the PM PLUS™
(from the PLC), a message instruction would need to be set up to read register N10:1 and then handled appropriately within
the PLC because this is a floating point value in the PM controller.
Most, if not all older PLCs support CIP generic messaging. It would be worth your while to see if the PLC in use
supports CIP to minimize programming effort. Using CIP allows for reads and writes to/from the PLC directly
to the desired CIP address within the PM PLUS. All available PM PLUS™ CIP addresses are documented within
this user guide for each of the PM PLUS™ Lists/Parameters.