ElmoMC SimplIQ Digital Servo Drives-Bell Command Reference - Manual (Page 312)

In order to analyze the BH record, it is important to understand that the internal
representation of quantities in the controller is not in user units. For example, while
the user relates to motor current in amperes, the controller represents current
internally by the bits of the A/D that measures the current. The BH record uploaded
recorded currents (and other variables as well) in their internal representation units,
and also provides the scaling multiplier to relate it to user units. This way, no
multiplication inaccuracies are introduced to the BH records, and the CPU load is
minimized.
The recorded transmitted by the controller in response to a BH=n command is
described in the following table. The record includes 20 bytes of overhead, and
numerical record data. The variables in the table are translated into ASCII as
described previously.
Byte
Number Description Value Type
0 - 1 Variable type for user.
Field has no practical
significance. 0: Integer system parameter
1: Real system parameter
2: Integer user program
variable
3: Real user program variable Byte
2 - 3 Data width: number of hex
character of single transmitted
data item. 4: Short integer
8: Long integer Byte
4 - 7 Data length: actual number of
transmitted data items. Word
8 - 11 Variable time multiplier: number
by which TS must be multiplied
to obtain basic recording period. Depends on RP[0] value Word
12 - 19 Floating number factor, by which
every uploaded data item is
multiplied in order to convert it
to user units, such as amperes, or
counts/second. 32-bit float
number in
IEEE
format.
20 - 20+ (Data length) * (Data width) -1:
data items. Oldest record is
transmitted first, and most recent
record is transmitted last.
Words or
long
integers,
according
to data
width.
Table 10-7: BH Record Structure
BH record transmission time can be quite long. A record of 2000 long numbers is
approximately 8000 bytes, which take at least 4 seconds to transmit over RS-232 at a
baud rate of 19,200. During this time:
The user program continues to run normally.
CAN commands are accepted and processed normally.
SimplIQ for Steppers Application Note Development Aids
MAN-STECR (Ver. 1.1)
113