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The control operations implemented with DAS for Siemens H1 Protocol are upload,
download, start, stop, and status. Only one application program or user
may do one of these at any time.
3.2.3.1 Control Operation Communications
For control operations a special TSAP is used. This is predefined and may be changed. When doing control operations, the CPU is sometimes stopped and thus the dual port RAM is non-operative.
These control operations are NOT supported for S155U programmable controllers.
To do control operations one needs to use the CP-511 communication card which can communicate with the CPU even when it is stopped. In this configuration, the host is connected to the CP-535 card via Ethernet. The CP-535 is connected to the CP-511 by an RS-232 cable, and the CP-511 communicates with the CPU via the backplane.
To do control operations, the host sends a series of requests to the CPU by going through the CP-535 and the CP-511 cards. For example, for an upload, the host first finds the type and status of the CPU, then determines what memory records have been programmed in the programmable controller. It then requests the contents of each of these memory records and writes them to a file.
3.2.3.2 Model S135U Communications
Model S135U of the Siemens programmable controller allows for multiple CPU cards
within the same programmable controller. To coordinate between the CPUs there is
a special Coordinator/MUX card.
Model S135U programmable controllers do not need the CP-511 card. The CPU may be connected directly to the CP-535 using a similar RS-232 cable as in the direct connection above. As such, when the CP-535 is connected directly to the CPU card, all control operations are done only to that CPU as if there are no other CPUs in the programmable controller.
The RS-232 cable may also be connected between the CP-535 card and the Coordinator card. In this configuration, control operations may be done to any of the CPU's in the programmable controller without changing the position of the cable. The Coordinator card is responsible for routing the control operation to the appropriate CPU.
3.2.3.3 Common Steps
Before doing the actual upload, download, start, stop or status, the
following steps need to be performed:
Then, perform the various steps specific to the control operation. When
the whole operation is finished, or if there is an error condition,
then abort the connection to the special TSAP.
3.2.3.4 Start and Stop
The start and stop functions change the operating mode of a device. The start function enables outputs and the stop function disables outputs.
Devices can control complex and perhaps dangerous industrial processes. Do not use the start and stop functions until you take the required safety precautions and put required operating restrictions into effect. See the manufacturer's documentation for specific safety precautions. |
The following are the steps to start the CPU:
The following are the steps to stop the CPU:
| Qualifier | Value | Description |
|---|---|---|
| START_OPTIONS | CPUn | For the model S135U, this specifies the CPU to be started |
| STOP_OPTIONS | CPUn | For the model S135U, this specifies the CPU to be stopped |
To start the second CPU of a model 135 programmable controller type the following.
DCM> START SIE_135 /START_OPTIONS=CPU2 |
To stop the CPU of a model 150 programmable controller type the following.
DCM> STOP SIE_150 |
The upload function transfers the contents of a device's memory to an OpenVMS file. The download function transfers the contents of an OpenVMS file to a device's memory.
The following are the steps for the upload operation:
After finishing the common steps, the DAS for Siemens H1 Protocol asks for the directory layout of the memory of the programmable controller. For each data area, it obtains all data records and writes them to file.
The following are the steps for the download operation:
When downloading to the CPU, one needs to inform the CPU that there is a new record. The CPU makes the proper entry in its directory and readies itself to accept the new record. If for whatever reason it can not do so, it replies with a protocol error and the download operation is terminated.
In this case, the memory contents are left in an unknown state.
When attempting a new download, the memory contents are cleared again, thus retrying the download operation from a cleared condition.
Note that the memory contents of the CPU are cleared first, hence the CPU should not reject the records unless there is an error in the OpenVMS file.
Upload and Download Qualifiers
| Qualifier | Value | Description |
|---|---|---|
| DEVICE_FILE | CPUn | For the model S135U, this specifies the CPU to be uploaded or downloaded. |
To upload the memory contents of the third CPU of a model 135 programmable controller, type the following:
DCM> UPLOAD SIE_135 DUA0:[LOGIC_FILES]PROG_3.DAT /dev=CPU3 |
To download to the memory of a CPU of a model 135 programmable controller connected directly to the CP-535 card, type the following:
DCM> DOWNLOAD SIE_135 DUA0:[LOGIC_FILES]PROG_ONE.DAT |
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