# load tclvisa package into Tcl shell
package require tclvisa

# get handle to default resource manager
if { [catch { set rm [visa::open-default-rm] } rc] } {
  puts stderr "Error opening default resource manager\n$rc"
  exit
}

# open device
set visaAddr "TCPIP0::10.80.84.54::lan0::INSTR"
if { [catch { set vi [visa::open $rm $visaAddr] } rc] } {
  puts "Error opening instrument `$visaAddr`\n$rc"
  # `rm` handle is closed automatically by Tcl
  exit
}

# Set proper timeout
fconfigure $vi -timeout 500

# Send command to instrument. New line character is added automatically by `puts`.
puts $vi "*CLS"

# Send command to query device identity string
puts $vi "*IDN?"

# Read device's answer. Trailing new line character is removed by `gets`.
set id [gets $vi]

puts "Identity of `$visaAddr` is `$id`"

# close channels
close $vi
close $rm