Read Holding Register Data (H03 or 03) - PENN Controls - VFD68Bxx - VFD68Cxx - VFD68Dxx - Three‐Phase Motor Speed Controller - VFD68 Three‐Phase Variable Frequency Drive

VFD68 Variable Frequency Drives Technical Bulletin

PENN Controls
Product name
VFD68 Three‐Phase Variable Frequency Drive
Document type
Technical Bulletin
Part number
Document revision
Revision date

Can read the description of the following items:

  1. system environment variables
  2. real-time monitor
  3. fault history
  4. VFD parameters assigned to the holding register area
Table 1. Query Message
Subordinate Address Function Starting Address Number of Points CRC Check
(8 bit) H03 (8 bit) H (8 bit) L (8 bit) H (8 bit) L (8 bit) L (8 bit) H (8 bit)
Table 2. Normal Response Message
Subordinate Address Function Byte Count Data CRC Check
(8 bit) H03 (8 bit) (8 bit) H (8 bit) L (8 bit) ...

(n x 16 bit)

L (8 bit) H (8 bit)
Table 3. Query Message Description
Message Description
Subordinate Address Address to which the message is sent. Broadcast communication cannot be made (0 is invalid).
Function Set H03
Starting Address Set the address at which holding register data read is started

Starting address = starting register address (decimal)-40001

For example, setting the starting address 0001 reads the data of the holding register 40002.

Number of Points Number of holding registers from which the data is read (125 maximum).
Table 4. Normal Response Message Description
Message Description
Byte Count The setting range is H02 to H14 (2 to 20). The byte count is set at twice the number of points.
Data: Read Data The number of data to be read equals the number of points. Data are read in order of high byte and low byte, and set in order of starting address data, starting address+1 data, starting address +2 data, and so forth.