ChkSumType (Checksum Method)

Specifies the method of the checksum calculation. The options are:

Code Description
1 CCITT CRC16 x16+x12+x5+1 (Xmodem, seed of 0).
2 CRC16 used by ModBus.
3 CRC16 used by ModBus with 0 initializer.
4 CCITT CRC32 used by Campbell Scientific BMP3 protocol.
5 Campbell Scientific signature.
6 Campbell Scientific signature nullifier.
7 Sum all the bytes and mod by 256.
8 Sum all the bytes and mod by 8192 (used by Campbell Scientific array-based dataloggers).
9 Checksum which performs exclusive OR on all the bytes; for example, first byte XOR second byte XOR third byte XOR… last byte.
10 CRC16 with seed of 0 and XOR polynomial of &hA001.
11 CRC16 with seed of &hFFFF and XOR polynomial of &hA001.
12 CRC16 with seed of 0 and XOR polynomial of &h8408.
13 CRC16 with seed of &hFFFF and XOR polynomial of &h8408.
14 CRC16 reverse bit order with seed of 0 and XOR polynomial of &hA001.
15 CRC16 reverse bit order with seed of &hFFFF and XOR polynomial of &hA001.
16 CRC16 reverse bit order with seed of 0 and XOR polynomial of &h8408.
17 CRC16 reverse bit order with seed of &hFFFF and XOR polynomial of &h8408.
18 CCITT CRC16 ITU/X25.
19 CRC16 UKMO (UK Met office).
22 CRC ClosedDNP3 Distributed Network Protocol is a set of communications protocols used between components in process automation systems. Its main use is in utilities such as electric and water companies. (note that DNP is little-Closedendian Endianness refers to byte order. With the little-endian format, bytes are ordered with the least significant byte (the "little end") first. With the big-endian format, bytes are ordered with the most significant byte ("big end") first. The CR300, GRANITE 9, and GRANITE 10 dataloggers use the little-endian format. The CR800, CR1000, CR3000, CR6, CR1000X, and GRANITE 6 use the big-endian format. Byte order when sending string variables as serial data is identical in big-endian and little-endian CSI dataloggers. Only numeric values sent as multiple bytes require attention to big-endian and little-endian issues. and the datalogger is big-endian. Use MoveBytes to convert Endianess.)
23 Returns the sum of all bytes with no masking.
24 Fletcher-16.
25 SHA1. This option requires an additional parameter that is a destination array that can hold 20 bytes.
26 SHA1, base 64 encoded. This option requires an additional parameter, typed as a string that can hold 29 characters. The result is null-terminated.
27 HMAC SHA1. This option requires three additional parameters: a destination array that can hold 20 bytes, a key, and the length of the key. If length is 0, the length of the key is used.
28 HMAC SHA1, base 64 encoded. This option requires three additional parameters: a destination array typed as a string that can hold 29 characters, a key, and the length of the key. If length is 0, the length of the key is used.
29 ClosedMD5 16 byte checksum of the TCP/IP VTP configuration.. This option requires an additional parameter that is a destination array that can hold 16 bytes.