Ideas in Measuring ..
TECHNIQUES LIMITED
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LDU 68 Series Manual
Setting
Master ( PC / PLC ) sends
LDU XX.X responds
Result
IO_0001
OK
Output 0 active
IO_0010
OK
Output 1 active
IO_0011
OK
Output 0+1 active
Please note that the status of the logic outputs is normally determined by the internal setpoint (see
section 5.10) and therefore setting the logic output status using the IO command is not allowed
unless enabled by the IM command
. The status of the outputs can then be changed by issuing
the IO command followed by the appropriate 4 digit code. For example if IO 0001 was sent to the
LDU, the output 0 will be activated (FET conducting).
Request
Master (PC / PLC) sends
LDU XX.X responds
Result
IO
IO:0001
IO:0010
IO:0011
Output 0 active
Output 1 active
IO
IO
Output 0 & Output 1 active
With this command you can read the status of the two logic outputs. The outputs are normally
internally controlled by the setpoint values (See section 5.10). The outputs can however be
controlled by the host system
if they have been enabled by the IM command
. If the IO command
is issued without any parameters the response shows the status of the logic outputs in the form of
a four digit code where 0 = false and 1 = true (outputs are normally open, open drain MOSFETs),
the least significant bit corresponding to Output 0 etc.
IO Read/Modify the status of the output channels
Master (PC / PLC) sends
LDU XX.X responds
Result
IN
IN:0001
IN:0010
IN:0011
Input 0 active
Input 1 active
IN
IN
Input 0 & Input 1 active
This command is sent without any parameters and reads the status of the two logic inputs. The
response is in the form of a 4 digit code where 0= false and1 = true (inputs are active ‘high’), the
least significant bit corresponding to logic input 0 etc .
IN Read the status of the two logic inputs
Issue 1h
The LDU 68.x has 2 independent logic inputs and 2 independent logic outputs. The inputs and
outputs can be configured and controlled completely via the LDU. The logic inputs can be read
directly by the host application and the 2 logic outputs have
additional control features which
allow the user total control over the configuration and action of each output channel. T
he
logic outputs are usually controlled internally via the setpoint commands but can be configured to
be controlled externally by using the IM command.
The following group of commands allows the status of the 2 logic inputs to be read or modified and
the logic outputs to be configured for internal or external control.
The use of the setpoint commands (Sn, Hn, An) are explained in the following chapter 5.10
5.9 Commands for external I/O control - IN, IO, IM
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LDU 68 Series Manual
Ideas in Measuring ..
TECHNIQUES LIMITED
The logic outputs can be controlled by the host application (as opposed to the normal internal
setpoints) if they are enabled by the IM command and the appropriate 4 digit code. If this
command is issued without any parameters, the response shows which of the logic output are
enabled. The response is in the form of a 4 digit code where 0= false and1 = true (inputs are active
‘high’), the least significant bit corresponding to logic input 0 etc .
IM Control of the logic outputs by the host application
Request
Note: When reading the status of the logic outputs using the IO command, the setpoint status will
be returned regardless of the IM setting. Sending IM 0000 disables the external logic output
control. Factory default:- IM= 0000
Setting
Master (PC / PLC) sends
LDU XX.X responds
Result
IM_0001
OK
OK
OK
Enable Output 0
Enable Output 1
IM_0010
IM_0011
Enable Output 0 & Output 1
Master (PC / PLC) sends
LDU XX.X responds
Result
IM
IM:0001
IM:0010
IM:0011
Output 0 Enabled
Output 1 Enabled
IM
IM
Output 0 & Output 1 Enabled
To enable the logic outputs to be controlled by the host application the IM command must be
issued together with a 4 digit code. A “1” bit in the code enables the corresponding logic output to
be controlled by the host application using the IO command. A “0” in the code leaves the
corresponding logic output controlled by the internal setpoint. Logic output 0 is again the least
significant bit.
Issue 1h
