B+K precision 8500 Benutzerhandbuch Seite 50

# Set DC load to remote mode.
import serial
length_packet = 26
def DumpCommand(bytes):
assert(len(bytes) == length_packet)
header = " "*3
print header,
for i in xrange(length_packet):
if i % 10 == 0 and i != 0:
print
print header,
if i % 5 == 0:
print " ",
s = "%02x" % ord(bytes[i])
if s == "00":
s = chr(250)*2
print s,
print
def CalculateChecksum(cmd):
assert((len(cmd) == length_packet - 1) or (len(cmd) ==
length_packet))
checksum = 0
for i in xrange(length_packet - 1):
checksum += ord(cmd[i])
checksum %= 256
return checksum
def main():
port = 3
baudrate = 38400
sp = serial.Serial(port, baudrate) # Open a serial connection
# Construct a set to remote command
cmd = chr(0xaa) + chr(0x00) + chr(0x20)
cmd += chr(0x01) + chr(0x00)*(length_packet - 1 - 4)
cmd += chr(CalculateChecksum(cmd))
assert(len(cmd) == length_packet)
# Send command to DC load
sp.write(cmd)
print "Set to remote command:"
DumpCommand(cmd)
# Get response from DC load
response = sp.read(length_packet)
assert(len(response) == length_packet)
print "Response:"
DumpCommand(response)
main()
DC-Lasten der Serie 8500
# Number of bytes in a packet
# COM4 for my computer
Copyright by Testec Elektronik GmbH
# First three bytes
Seite 50 von 82