Minarik
Variable Speed AC Motor Drives
Modbus Control of Minarik
AC200 Series Drives
INSTALLATION AND OPERATION INSTRUCTIONS
Document Number: 250-0307
Scope
This document is intended to define the specifics required for serial communication with Minarik Corporation Standard AC200
Series drives for control, status monitoring, and programming parameters. A familiarity with normal drive capabilities and
operations is assumed. If this is not the case, please refer to the appropriate Minarik Installation and Operation manual as necessary.
Modbus
Details
A) Minarik Drives running the Modbus communication protocol use the RTU (Remote Terminal Unit) transmission mode and are
slaves only. Therefore, the device communicating with the drives must be a Modbus Master. The baud rate is 9600, no parity
(two stop bits). There are provisions for Odd parity 1 stop bit and Even parity 1 stop bit as well. The bit sequence is:
B) At this time the Minarik drives do not support the broadcast function of the protocol.
Minarik
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901 E. Thompson Ave.
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Glendale, CA 91201
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Ph: (800)646-2745
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Fax: (800) 394-6334
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www.minarikcorp.com
C) The function codes supported by Minarik drives are:
1. 03 - Read Holding Register (4X references). In general only one register is read at a time. However there are a few
limited exceptions.
Exception One:
a) Register #24 (Modbus Register #25), Drive Status, can also be read as a group of 6 words.
Exception Two:
Minarik uses a method of reading a group of related registers that may not be consecutive within the drive memory
map. When this is done for the registers below, the response from the drive will be for the number of words
requested but will not be with consecutive registers.
b) Register #100 (Modbus Register #101), Fault history, should be read as a group of 4 words.
c) Register #101 (Modbus Register #102), Software version, should be read as a group of 4 words.
2. 04 - Read Input Register (3X references). As with function 03, read one register at a time except where noted.
3. 06 - Preset Single Register (4X references). Write single register.
4. 16 - Preset Multiple Register (4X references). Although the function is for multiple registers, will accept only a single
register to be written.
5. Note: Do not differentiate between 4X and 3X references, function codes 03 and 04 are treated identically.
Warning
Modbus 3X and 4X Registers are numbered starting at 1. However, when transmitted to a slave over the serial link, the actual
address transmitted is one less. This is because the addresses are numbered starting from 0. Minarik register numbers are also
numbered starting from 0. Therefore, Minarik register numbers always correspond exactly with the address transmitted. As a
result, MODBUS REGISTER NUMBERS ARE ALWAYS ONE GREATER THAN MINARIK REGISTER NUMBERS.
WHENEVER THE WORDS “REGISTER #xx” APPEAR, IT SHOULD BE ASSUMED THAT THEY MEAN “MINARIK
REGISTER xx” and the Modbus Register number will be one larger. In some instances we may show both for clarity. For
example: “Register #24 (Modbus Register #25) . . .”
Start bit
1
2
3
4
5
6
7
8
Stop bit
Stop bit
Data