Grundfos DDI Series

5
6.2 Communication between the PROFIBUS master
and the pump
6.2.1 General / classification of remote control and local
operation
During PROFIBUS operation, the pump can still be operated
locally or controlled (remotely) via the PROFIBUS master
(e.g. SPS).
It is possible to allow local operation in addition to remote control
via PROFIBUS-DP, but this can also be locked via the code.
Independently of the pump control mode, the current data such
as dosing volumes, chamber pressure, pump status messages
and error messages are sent from the pump (bus slave) to the
PROFIBUS master for further processing.
Remote control via PROFIBUS-DP
In remote control via PROFIBUS, commands are sent from the
PROFIBUS master (e.g. SPS) to the bus slaves (e.g. the pump),
which means that the pump is controlled via control signals from
the PROFIBUS master.
When using remote control via PROFIBUS, the following
operating modes are available:
• manual
• contact
• current control 0-20 mA
• current control 4-20 mA.
Remote on/off via PROFIBUS-DP
Starting and stopping the pump using remote control via
PROFIBUS have the same effects on the pump as external
remote off via a contact signal at the "remote on/off" input port.
External remote off and switching off via PROFIBUS switch the
pump off independently of each other.
Local operation
When operating the pump locally, the settings are made directly
on the pump.
During local operation, all operating modes in manual, contact or
current control are available:
• manual
• contact
• current control 0-20 mA
• current control 4-20 mA
• batch dosing with manual start
• batch dosing with contact start
• timer mode with manual start
• timer mode with contact start.
Local operation can be restricted using the code function or
locking "run" (locks the "Start/Stop" button).
6.3 Data protocol
The control of the pump can be different, depending on the
PROFIBUS master and the visualisation software.
For remote control of the pump via PROFIBUS and for feedback
from the pump, the following basic functions and setting options
are available.
6.3.1 Remote control of pump via PROFIBUS-DP
Data flow from the PROFIBUS master to the pump
4 bytes are available for controlling the pump:
To control the pump using the PROFIBUS master, proceed as
follows:
1. Select the operating mode (byte 1/bits 0, 1)
– manual
– contact
– current control 0-20 mA
– current control 4-20 mA.
2. The operating mode is enabled when bit 4 changes from
0to1.
3. Enter the setpoint (bytes 3, 4).
Enter hexadecimal or binary as a binary number with 16 bits.
The setpoint depends on the operating mode:
– For manual operating mode: Setpoint = volume flow.
DDI 209: Enter value in ml/h from 4 ml/h to 50,000 ml/h.
DDI 222: Enter value in cl/h from 7.5 cl/h to 15,000 cl/h.
– For contact operating mode: Setpoint = volume per contact.
DDI 209: Enter value in µl from 1 µl to 7,860 µl.
DDI 222: Enter value in µl from 111 µl to 55,500 µl.
– For current control operating mode 0-20 mA/4-20 mA:
Setpoint = gradient of flow rate.
DDI 209: Enter the dosing rate at 20 mA in ml/h from 4 ml/h
to 50,000 ml/h.
DDI 222: Enter the dosing rate at 20 mA in cl/h from 7.5 cl/h
to 15,000 cl/h.
4. The setpoint is enabled when bit 5 changes from 0 to 1.
Note
Pump settings (in local operation) are not saved
as new setpoints in the PROFIBUS master.
Instead they are simply sent to the PROFIBUS
master as status messages.
As soon as the command "Release setpoint" or
"Release operating mode" is executed in the
PROFIBUS master (automatically or manually),
the settings from the PROFIBUS master apply.
Byte Data type Data length [byte]
1Byte 1
2Byte 1
3, 4
Unsigned 16
Highbyte, Lowbyte
2
Bit
Byte 1:
Set and release operating mode, enter setpoint
0, 1
Bit 1
0
0
1
1
Bit 0
0
1
0
1
Operating mode
Manual
Contact
Current control 0-20 mA
Current control 4-20 mA
2, 3 Reserve
4 0 -> 1 = confirmation (release) of operating mode
5 0 -> 1 = confirmation (release) of setpoint
6
Transfer of
actual
value
0 = volume flow
1 = pressure value (mbar) when pressure
control is enabled
7 Reserve
Note
The maximum flow rate of the pump must not be
exceeded!
For current control operating mode, the setpoint
(with or without weighting) must always be
assigned with reference to 20 mA.
Please see the additional description of current
control in the installation and operating
instructions for the DDI pump!