Manual MCD
+
MA 2102-A005 GB
38
The checksum is defined by summing up all bytes, beginning with the address byte and
including the separator (:) in an exclusive-OR-operation (
⊕
):
CS = address_H address_L
⊕
data byte 1
⊕
data byte 2 . . .
⊕
data
byte n
⊕
separator
The checksum is calculated as one 8-bit binary value (00
h
to FF
h
). This byte is taken apart
in its upper and lower byte (nibbles). After the HEX values of the two nibbles have been
transferred to the corresponding two ASCII characters (0 to 9 instead of 0
H
to 9
H
and
A to F instead of A
H
to F
H,
that means
to each nibble 30
H
or rather 37
H
is mathematically
added)
,
the checksum is written into the telegram.
The power stage also calculates (Exclusive OR) the checksum of the received data. The
telegram will be rejected if a difference to the received checksum is detected.
If there is no need to validate the contents of the telegram, the checksum monitoring can
be set off. Instead of the checksum bytes, two X characters will be accepted by the power
stage. As well, telegrams without checksum and also without : (separator) will be
accepted, e.g.:
Example:
<STX>
| 1 | R | 4 | 0 | : | X | X |
<ETX>
or
Example:
<STX>
| 1 | R | 4 | 0 |
<ETX>
9.2 Operating Parameters
The operating parameters are stored in a permanent memory of the power stage.
In the following table the operating parameters are defined with
W
for
w
rite,
R
for
r
ead and
X
for e
x
ecute.
For current values reading or writing is applied:
Integer value x 1/10 = valid current or voltage value
Example: 48 x 1/10 = 4.8 (A
r.m.s
)
The MCD instruction set mostly consists of one-byte-instructions, this means, that from the
second byte the data for the instruction will follow.
The instructions for additional parameters with instruction code
P
are two byte instructions.
The data will begin on the 3rd byte in these instructions.
By
L
or
U
input after the instruction code the maximum permissible instruction limits, by
I
input after the instruction code the function of the instruction are displayed. By
S
and
E
s
cale and unit (
E
inheit) of current and time values can be read.
