Control Data Systems Versa Router 950, User Manual

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Ref.no.: 003274/Revision 2.4 @2019 Control Data Systems Page 165 | 201
a. start address - decimal integer, between 0 and 65535, representing the start address of the
Modbus register;
b. word count - decimal integer, between 1 and 125, representing the number of 16-bit
Modbus words allocated for this Wireless HART data element;
c. EUI-64 - string of 16 hex digits, representing the 8 bytes of a device’s EUI-64 address;
d. register type: device_variable , gw_info or gw_code_word are the three register types
supported;
When register type is device_variable , the following parameters must be specified:
e. the burst message you want to map;
f. device variable code;
g. device state - decimal integer, 0 and 2 with the following meaning:
•
0 – the Wireless Hart device variable is mapped onto the chunk of registers, starting
from address <start_addr>. The value should be interpreted as 4 bytes float; Wireless
Hart Communication errors (e.g. device not joined) will make addressing these registers
return the Modbus exception 0x04 (slave device failure);
•
2 – the Wireless Hart device variable is mapped onto the chunk of registers, starting
from address <start_addr>+1. The value should be interpreted as 4 bytes float. At
address <start_addr> there is a
device state register generated by the Modbus server
which reflects the state of the Wireless Hart communication; the value should be
interpreted as 16-bit big-endian integer with the following values:
o
128: Device Joined with fresh data;
o
8: Device NOT joined, and no data read so far;
o
20: Device NOT joined but with stale data;
o
24: Device Joined but no data read so far;
o
4: Device Joined but with stale data.
When register type is gw_info , general gateway information will be exposed to Modbus, using the
following registers ( Table 7.2 ):
Table 7.2 General GW information (HART)
Register Item exposed Observation
<start_addr> + 0 Number of devices currently
connected.
16bit big-endian integer
<start_addr> + 1 Total number of burst messages. 16bit big-endian integer
<start_addr> + 2 Versa Router MAC. 3 words * 16bit big-endian
unsigned integer
Note : For register type gw_info the <word_cnt> must be 5.
When register type is gw_code_word , the gateway’s code word will be exposed to Modbus; The code
word is read-only.
Note : For register type gw_code_word , the <word_cnt> should be 16 or less.