C.4: Application Layer; C.5: Error Reply - Electro Industries Shark 200 Installation & Operation Manual

C.4: Application Layer

®
In the Shark 200 meter, DNP Lite supports the Read function, Write Function, the Direct Operate
function and the Direct Operate Unconfirmed function.
The Read function (code 01) provides a means for reading the critical measurement data from the
meter. This function should be posted to read object 60 variation 1, which will read all the
available Class 0 objects from the DNP Lite register map. See register map in Section C.6. In
order to retrieve all objects with their respective variations, the qualifier must be set to ALL
(0x06). See Section C.7 for an example showing a read Class 0 request data from the meter.
The Write function (code 02) provides a mean for clearing the Device restart bit in the Internal
Indicator register only. This is mapped to Object 80, point 0 with variation 1. When clearing the
restart device indicator use qualifier 0. Section C.7 shows the supported frames for this function.
The Direct Operate function (code 05) is intended for resetting the energy counters and the
demand counters (minimum and maximum energy registers). These actions are mapped to Object
12, point 0 and point 2, that are seen as a control relay.
The relay must be operated (On) in 0 msec and released (Off) in 1 msec only. Qualifiers 0x17 or
x28 are supported for writing the energy reset. Sample frames are shown in Section C.7.
The Direct Operate Unconfirmed (or Unacknowledged) function (code 06) is intended for
asking the communication port to switch to Modbus RTU protocol from DNP Lite. This
switching is seen as a control relay mapped into Object 12, point 1 in the meter. The relay must
be operated with qualifier 0x17, code 3 count 0, with 0 millisecond on and 1 millisecond off,
only.
After sending this request the current communication port will accept Modbus RTU frames only.
To make this port go back to DNP protocol, the unit must be power-recycled. Section C.7 shows
the constructed frame to perform DNP to Modbus RTU protocol change.

C.5: Error Reply

In the case of an unsupported function, or any other recognizable error, an error reply will be generated
®
from the Shark 200 meter to the Primary station (the requester). The Internal Indicator field will report
the type of error: unsupported function or bad parameter.
The broadcast acknowledge and restart bit, are also signaled in the internal indicator but they do not
indicate an error condition.
E
Electro Industries/Gauge Tech Doc# E149701 C-
2