The document describes using Modbus to change and control the profile operation of PXU units.
v1.51 or later
The PXUs allow for configuring up to 16 profiles, with up to 16 steps each. Configuring the unit via the front panel buttons can be difficult, but using Modbus can make it easier.
Refer to the PXU Manual for an explanation of the profile operation and the full Modbus register list. Please note that the register numbers shown in the manual and document do not include the leading address components that are often used when configuring Modbus devices. For instance, if using a Red Lion HMI as the master, the address of the Process value will be 400001, if using another Modbus master that uses 5-digit addressing (such as Modscan) the register will be 40001.
There is a basic single profile Crimson 3.1 file for a G09 attached to this article.
The following Modbus holding registers will be used in this document:
|27||Current Profile Segment|
|28||Profile Segment Time Remaining|
|29||Starting Profile Number|
|30||Starting Segment Number|
|80||Setpoint Control Mode|
|1091||Profile Deviation Error|
|1092||Profile Error Band Timeout|
|1101-1612||Profile Setpoints and Times|
|1631-1646||Number of Segments|
Register 1: a 16-bit integer value that represents the top line of the PXU. The decimal place is implied, so if the PXU is reading 100.0, the Modbus register will have a value of 1000.
Register 2: a 16-bit integer value that represents the bottom line of the PXU. The decimal place is implied, so if the PXU is showing 100.0, the Modbus register will have a value of 1000.
Register 17: a value of 0 (automatic control) or 1 (manual control).
Register 18: a value from 0 to 4. 0 - Stop, 1 - Run, 2 - End (profile mode), 3 - Pause (profile mode), 4 - Advance Profile (profile mode).
Register 26: a value from 0 to 15 (0-F) indicating the profile that is currently running.
Current Profile Segment
Register 27: a value from 0 to 15 (0-F) indicating the profile segment that is currently running.
Profile Segment Time Remaining
Register 28: a value, in tenths of minutes, that shows how much time is remaining in the current segment.
Starting Profile Number
Register 29: a value from 0 to 15 (0-F) indicating the profile that will be run when the Controller Status is changed to 1 (run).
Starting Profile Segment Number
Register 30: a value from 0 to 15 (0-F) indicating the segment of the Starting Profile Number that will be run when the Controller Status is changed to 1 (run).
Setpoint Control Mode
Register 80: a value from 0 to 2. 0 - SP control mode, 1 - Profile Control Mode, 2 - Remote Setpoint Mode.
Profile Deviation Error
Register 1091: a value, in display units, used to enter profile delay mode. * refer to the manual for more information.
Profile Error Band Timeout
Register 1092: a value, tenths of minutes, used to alarm if the profile is in delay mode for too long. * refer to the manual for more information.
Profile0's Modbus Registers
Profile Segment Setpoints and Profile Segment Times
The setpoint values are in the same units as the input. The time values are in tenths of minutes.
* The Profile1's registers start at 1133, following the same format (odd registers are the SP and even registers are the time); followed by the remaining profile values, again in the same format.
Number of Segments (End Segment)
Register 1631: a value between 0 and 15 (0-F), indicating which segment is the last segment of the profile.
* The next 14 registers are the end segments for each of the other profiles.
Register 1651: a value between 0 and 99, indicating how many times this profile should run (0 will continue running the profile indefinitely).
* The next 14 registers are the cycle repeats for each of the other profiles.
Register 1671: a value between 0 and 17, 0-15 represent profiles 0-F, 16 is End, and 17 is Stop. This feature allows multiple profiles to be chained together, useful if the application requires more than 16 segments.
* The next 14 registers are the link profiles for each of the other profiles.
Configuring, Running, and Monitoring a Profile via Modbus
- If applicable, set the Profile Deviation Error (1091) and Profile Error Band Timeout (1092), these values will be used for all profiles that are configured.
- Configure the Number of Segments (1631-1646), Cycle Repeat (1651-1666), and Link Profile (1671-1686) values for each profile, according to how many segments are in each given profile. Only the profiles that will be used need to be configured.
- Configure the Profile Segment Setpoints and Profile Segment Times (1101-1612) for each segment of each profile that will be used. Only the segments that will be used need to be configured.
Running a Profile
- Set the Starting Profile Number (29) and the Starting Segment Number (30) to the profile and segment that the system will begin on.
- Set the Setpoint Control Mode (80) to 1 (Profile). * this will automatically change Controller Status (18) to 0 (Stop).
- Set the Controller Status (18) to 1 (Run) to begin the profile.
Monitoring a Profile
- Setpoint (2) will show the current setpoint value that the system is controlling to, it will change along with the profile during ramping segments.
- Current Profile (26) will show which profile is currently running.
- Current Profile Segment (27) will show which segment of the Current Profile (26) is running.
- Profile Segment Time Remaining (28) will show how much time, in tenths of seconds, remains in the Current Profile Segment (27)
It is the customer's responsibility to review the advice provided herein and its applicability to the system. Red Lion makes no representation about specific knowledge of the customer's system or the specific performance of the system. Red Lion is not responsible for any damage to equipment or connected systems. The use of this document is at your own risk. Red Lion standard product warranty applies.
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