User guide

CobraNet Programmer’s Reference

Management Interface Variable Reference

6.2 Data Types

6.2.1 DisplayString

A DisplayString is an ASCII string comprised entirely of printable characters.

24-bit HMI: The first word indicates the length of the string in characters. Data is stored

three characters per 24-bit word. Character order is MS, Middle, LS. For DisplayString

variables, documented Size indicates the largest possible word size of the variable. Size

includes the length field. The maximum allowable characters for a DisplayString variable

is (Size-1)×3.

32-bit HMI: The first word indicates the length of the string in characters. Data is stored

four characters per 32-bit word. Character order is MS, MH, ML, LS. For DisplayString

variables, documented Size indicates the largest possible word size of the variable. Size

includes the length field. The maximum allowable characters for a DisplayString variable

is (Size-1)×4.

6.2.2 OID

An SNMP object identifier is the numeric name of an SNMP variable. OIDs are also used

for other purposes including system-unique identifiers.

24-bit HMI: OIDs are presented in their native BER encoding. The first word indicates the

length of the encoding in bytes. Data is stored three octets per 24-bit word. Character

order is MS, Middle, LS. For OID variables documented Size indicates the largest

possible word size for the variable. Size includes the length field. The maximum number

of octets for the OID variable encoding is (Size-1)×3.

32-bit HMI: OIDs are presented in their native BER encoding. The first word indicates the

length of the encoding in bytes. Data is stored four octets per 32-bit word. Character order

is MS, MH, ML, LS. For OID variables documented Size indicates the largest possible

word size for the variable. Size includes the length field. The maximum number of octets

for the OID variable encoding is (Size-1)×4.

6.2.3 IpAddress

An IpAddress is a 32-bit internet protocol (IP) address.

24-bit HMI: Data is stored in the most-significant 16 bits of 2 consecutive 24-bit words as

shown in Tabl e 10 . The least-significant 8 bits of each location are read as zero and must

be written as zero.

32-bit HMI: Data is stored in a single 32-bit word as illustrated below.

Table 10. IP address Layout, 24-bit Platforms

MS Middle LS

Word 1

IP address byte 2 IP address byte 1 0

Word 2

IP address byte 4 IP address byte 3 0

Table 11. IP address Layout, 32-bit Platforms

MS MH ML LS

IP address byte 2 IP address byte 1 IP address byte 4 IP address byte 3