Emerson Mentor MP User Manual

Parameter structure
Keypad and display
Parameter x.00
Parameter
description
protocol
Performance
6.1
.2
Physical
layer
and
UART
6.1.3
Reading
a
parameter
The
command
to
read
a
parameter
is:
If
the
parameter
to
be
read
does
not
exist
the
End
of
transmission
excluding
the
STX
and
the
checksum,
i.e.
Checksum
=
M1
^
M2
^
P1^
P2
^
D1
^
D2
^
......
Dn
^
ETX.
The
checksum
is
an
unsigned
8
bit
value
and
if
the
checksum
is
less
than
32
then
32
is
added
to
the
calculated
checksum.
6.1.4
Writing
to
a
parameter
The
command
to
write
to
a
parameter
is:
If
the
message
is
correct
and
the
parameter
exists
the
response
is:
The
length
of
the
data
field
varies
depending
on
the
number
of
The
following
rules
apply
to
the
data
field:
format
6 Serial communications
protocol
6.1 ANSI communications protocol
6.1.1 Introduction
Mentor MP supports an ANSIx3.28 type comms protocol as supported
Advanced parameter
descriptions
Serial comms
by previous Control Techniques products with some modification to
allow access to 32 bit parameters. This chapter describes the
implementation of the protocol for Mentor MP.
character (Ctl D) is returned.
The checksum is derived by exclusive ORing the message byte together
significant digits required to represent the value of the parameter. The
maximum length is 12 digits including the sign and decimal point if
present. The data field always starts with a sign, minus sign for negative
numbers, or a plus sign for zero and positive numbers. The field may
contain a decimal point, but this will not be before all the numbers in the
field or after all the numbers in the field. The following examples
demonstrate some possible data fields.
1. The maximum length is 12 characters.
2. The field may contain leading spaces, but not after any other
character.
3. A sign character is optional. No sign indicates positive.
4. A decimal point is optional. This can appear at any point in the data
field, but not before the sign or before 10 numbers (i.e. the value
written should not have more than 9 decimal places). If the decimal
point is not in the same position as used by the parameter some
accuracy may be lost or extra decimal places added (i.e. if +1.2345
is written to a parameter with one decimal place the result is +1.2, if
+1.2 is written to a parameter with three decimal places the result is
+1.200). It should be noted that parameters can only have 0, 1, 2, 3,
4, 5, or 6 decimal places.
5. The data field can contain up to 10 numbers, but the value even
ignoring decimal points must not exceed the range –2
31
to 2
31
-1.
If the parameter is written successfully an Acknowledge character (Ctl F)
is returned. If the parameter does not exist, the value written exceeds
the allowed parameter range or the data field rules are not obeyed an
Not acknowledge character (Ctl U) is returned.
The checksum is derived by exclusive ORing the message byte together
excluding the STX and the checksum, i.e. Checksum = M1 ^ M2 ^ P1^
P2 ^ D1 ^ D2 ^ ...... Dn ^ ETX. The checksum is an unsigned 8 bit value
and if the checksum is less than 32 then 32 is added to the calculated
checksum.
204 Mentor MP Advanced User Guide
www.onxcontrol.com Issue Number: 4
EOT
End
of
transmission
(Ctl
D)
A1
st
Drive address: 1 digit
A1
st
Drive address: 1 digit
A2
nd
Drive address: 2 digit
A2
nd
Drive address: 2 digit
STX
Start
of
text
(Ctl
B)
M1
st
Menu number: 1 digit
M2
nd
Menu number: 2 digit
P1
st
Parameter number: 1 digit
P2
nd
Parameter number: 2 digit
D1
st
Data: 1 digit
D2
nd
Data: 2 digit
-
-
Dn
Data:
nth
digit
ETX
End
of
text
(Ctl
C)
Checksum
STX
Start
of
text
(Ctl
B)
M1
st
Menu number: 1 digit
M2
nd
Menu number: 2 digit
P1
st
Parameter number: 1 digit
P2
nd
Parameter number: 2 digit
D1
st
Data: 1 digit
D2
nd
Data: 2 digit
-
-
Dn
Data:
nth
digit
ETX
End
of
text
(Ctl
C)
Checksum
EOT
End
of
transmission
(Ctl
D)
A1
st
Drive address: 1 digit
A1
st
Drive address: 1 digit
A2
nd
Drive address: 2 digit
A2
nd
Drive address: 2 digit
M1
st
Menu number: 1 digit
M2
nd
Menu number: 2 digit
P1
st
Parameter number: 1 digit
P2
nd
Parameter number: 2 digit
ENQ
Enquiry
(Ctl
E)
Attribute
Description
Physical
layer
2
wire
EIA485
Bit stream
Standard
UART
asynchronous
symbols
with
Non
Return to Zero (NRZ)
Symbol
Each
symbol
consists
of:
1 start bit
7 data bits (ASCII)
1 parity bit (even parity)
1 stop bit
Baud
rates
300,
600,
1200,
2400,
4800,
9600,
19200,
38400
Value
Data field
0
+0
(parameter
with
no
decimal
places)
0
+0.00
(parameter
with
2
decimal
places)
1.2
+1.2
-345.78
-345.78
123456
+123456

Emerson Mentor MP Specifications

General

Brand	Emerson
Model	Mentor MP
Category	DC Drives
Language	English