B&K Precision 8500-8526 - Manual User Manual

Page 50

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You can download a complete python program along with detailed documentation from our website
at

www.bkprecision.com

Here are the printed results when the above script is ran:

Set to remote command:
aa ·· 20 01 ·· ·· ·· ·· ·· ··

·· ·· ·· ·· ·· ·· ·· ·· ·· ··
·· ·· ·· ·· ·· cb

Response:
aa ·· 12 80 ·· ·· ·· ·· ·· ··

·· ·· ·· ·· ·· ·· ·· ·· ·· ··
·· ·· ·· ·· ·· 3c

The

·

characters represent the bytes with a value of

0x00

. This makes it easier to see the nonzero

bytes in the string.
The first byte of a command is always

0xaa

and the second byte is the address of the DC load. The

address should be set to 0. The third byte identifies the command "set to remote" and the fourth
byte is a 1, which means enable remote mode. If the fourth byte was 0, this command would set the
DC load to local mode.
The third byte of the response string is

0x12

, which means this is a packet that gives the status of

the last command sent. The fourth byte is

0x80

, which means the command completed

successfully.
On the DC load, you should see the

Rmt

annunciator turned on immediately after running the script.

You will also see the

Link

annunciator light up while communications are going on, then blink out

after a few seconds.
Press

Shift + Local

to set the DC load back to local mode.

We've learned two key things about the DC load:

1. Commands are always sent as 26 byte packets.
2. For any command you send to the DC load, you must also request the return of a 26 byte

packet. This returned packet will either be a status packet or an information packet
containing data you requested -- for example, the power level currently set.

Get in the habit of looking at the LEDs on the IT-E131 or IT-E132 interfaces. Every command you
send to the DC load should result in both the RX and TX LEDs blinking once. If this does not
happen, something is wrong with the code, interface, or instrument.

8500 DC Load Series

Version: 030614

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